Source: CORNELL UNIVERSITY submitted to
ANTIOXIDANT AND ANTICANCER ACTIVITIES IN FRUITS, VEGETABLES AND OTHER NATURAL PRODUCTS.
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
STATE
Reporting Frequency
Annual
Accession No.
0186990
Grant No.
(N/A)
Project No.
NYC-143300
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jul 1, 1999
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Project Director
Liu, R. H.
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
FOOD SCIENCE
Non Technical Summary
Relatively few studies in any experimental situation have attempted to use complex preparations which are more likely to have effects representative of the food itself. This research has a critical economic impact on NY State and US fruits growers and fruits industry, as the New York Apple Association and US apple Association plan concentrate much of their future marketing strategy around these findings.
Animal Health Component
(N/A)
Research Effort Categories
Basic
65%
Applied
35%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
5011199101034%
7011430103033%
7021440115033%
Knowledge Area
501 - New and Improved Food Processing Technologies; 701 - Nutrient Composition of Food; 702 - Requirements and Function of Nutrients and Other Food Components;

Subject Of Investigation
1199 - Deciduous and small fruits, general/other; 1430 - Greens and leafy vegetables; 1440 - Cole crops;

Field Of Science
1010 - Nutrition and metabolism; 1030 - Cellular biology; 1150 - Toxicology;
Goals / Objectives
The specific objectives are 1) to determine the levels of phytochemicals (phenolic acids and flavonoids) in common fruits, vegetables and other natural products in the American daily diet; 2) to determine the total antioxidant activity of common fruits, vegetables and other natural products by total oxyradical scavenging capacity assay. To rank the fruits, vegetables and other natural products in order of total antioxidant activity; and 3) to determine the ability of the extracts from common fruits, vegetables and other natural products to inhibit tumor cell growth in a colon cancer cell culture model and a liver cancer cell culture model in vitro.
Project Methods
We propose to analyze different fruits (apple, grape, cranberry, blueberry, orange, banana, and plum), vegetables (brussels sprouts, carrot, onion, cabbage, broccoli, and tomato), and other natural products for total falvonoids and phenolics, and total antioxidant activity. Extraction: Phytochemicals will be extracted from fruits, vegetables and other natural products by methods developed at this laboratory (Eberhardt, et al, 2000). The final extracts will be stored at -70 degrees Celsius until use. Briefly, the edible portion of the products will be weighed and homogenized in 80% chilled acetone. After filtration, the acetone extract will be rotary-evaporated and the final concentrates will be stored at -70 degrees Celsius until use. The antioxidant activity of the extracts will be determined by Total Oxyradical Scavenging Capacity (TOSC) assay in PI's laboratory. We have used this assay to evaluate the total antioxidant activity for vitamins and natural antioxidants. Antioxidant activity was assessed at four different time points (15, 30, 45, 60 minutes) and 6 different concentrations to determine the TOSC value. The TOSC value of each concentration of sample can be calculated using the integration of the area under the kinetic curve. The total antioxidant activity will be expressed as TOSC (umol vitamin C equivalent). The median effect dose (EC50) for all samples will be calculated by statistical software program. These values will be used to rank the samples based on their total antioxidant capacity, total phenolics and total flavonoids. We have developed a Colon cancer Caco-2 cell culture model and a liver cancer cell model to examine the ability of phytochemicals from fruit, vegetable, and other natural product extracts to inhibit cancer cell growth. Cell culture: Colon cancer Caco-2 cells are maintained in DMEM supplemented with 10 mM Hepes and 10% fetal bovine serum (FBS) at 37 degrees C and 5% CO2. HepG2 liver cancer cells are maintained in WME supplemented with 10 mM Hepes and 5% fetal bovine serum (FBS) at 37 degrees C and 5% CO2. Measurement of cell proliferation: 4x10 to the fifth of colon cancer Caco-2 cells in DMEM or HepG2 cells in WME will be placed into each well of 96 well flat bottom plates. The phytochemical extracts from 0, 5, 10, 20, 30, 40, and 50 mg apples will be added directly into the medium. Control cultures will receive the same amount of solvent as treated samples but without the phytochemicals. Proliferation will be assessed using the MTT assay (Mosmann and Fong, 1989). Cytotoxicity: Cytotoxicity will be determined by the inhibition of the uptake of neutral red dye by cells grown in 96-well plates. The cells will be treated with tested compounds in 0.2 ml medium/well. The phytochemical extracts from 0, 5, 10, 20, 30, 40, and 50 mg apples will be assayed in triplicates. CC50 value (50% cytotoxic concentration: drug concentration which induces a 50% inhibition of dye uptake vs. control cultures) will be calculated by linear regression analysis.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Breast cancer is the most commonly diagnosed cancer in women. Increased intake of fruits and vegetables has been consistently associated with a reduced risk of cancer. Apples are one of the largest contributors of fruit phenolics of all fruits consumed by Americans and contain a variety of bioactive compounds. Consumption of apples has been linked to reduced risk of cancer. We have reported apple extracts have potent antioxidant and antiproliferative activity in vitro. However, the molecular mechanisms of the anticancer properties of apple extracts are not completely understood. We showed that whole apple extracts had potent anti-cancer activity in a rat mammary cancer model. Rats were given the whole apple extracts (0, 3.3, 10.0 or 20.0 g/kg body weight) starting 2 weeks prior to 7, 12-dimethylbenz(a)anthracene (DMBA) administration and continuing for the 24 weeks. Rats treated with DMBA developed mammary tumors with 71.4 % tumor incidence. No tumors were detected in the negative control group untreated with DMBA. Application of low, middle and high doses of whole apple extracts, comparable to human consumption of 1, 3, and 6 apples per day, reduced the tumor incidence by 17, 39, and 44 percent, respectively, in a dose-dependent manner (p<0.01). Apple extracts also decreased the expression of proliferating cell nuclear antigen (PCNA), cyclin D1 and Bcl-2, and increased expression of Bax and apoptosis in vivo with increasing the apple extracts. These results demonstrate the potent capacity of fresh apples to suppress DMBA-initiated mammary cancers in rats. We also investigated the antiproliferative activity of apple extracts and quercetin 3-beta-D-glucoside (Q3G) by measurement of the inhibition of MCF-7 human breast cancer cell proliferation. Cell cytotoxicity was determined by the methylene blue assay. The two-way combination of apple plus Q3G was conducted. In this two-way combination, the EC50 values of apple extracts and Q3G were 2-fold and 4-fold lower than that of apple extracts and Q3G alone. The combination index (CI) values at 50% and 95% inhibition rate were 0.76 +/- 0.16, and 0.42 +/- 0.10, respectively. The dose-reduction index (DRI) values of the apple extracts and Q3G to achieve a 50% inhibition effect were reduced by 2.03 +/- 0.55, and 4.28 +/- 0.39-fold, respectively. The results suggest that the apple extracts plus Q3G combination possesses a synergistic effect in MCF-7 cell proliferation. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Our results showed that whole apple extracts significantly inhibited human breast cancer MCF-7 and MDA-MB-231 cell proliferation and induced G1 arrest in a dose-dependent manner. Apple extracts decreased expression of Cyclin D1 and Cdk4 proteins in a dose-dependent manner. These results suggest that the antiproliferative activities of apple extracts towards human breast cancer cells might be due to the modulation effects on cell cycle machinery. We also showed that whole apple extracts had potent anti-cancer activity in a rat mammary cancer model. Rats treated with the carcinogen developed mammary tumors with 71% tumor incidence during a 24-week study. Application of low, middle and high doses of whole apple extracts, comparable to human consumption of 1, 3, and 6 apples per day, reduced the tumor incidence by 17, 39, and 44 percent, respectively, in a dose-dependent manner (p<0.01). The tumor multiplicity decreased with increasing apple extracts. Apple extracts also decreased the expression of proliferating cell nuclear antigen (PCNA), cyclin D1 and Bcl-2, and increased expression of Bax and apoptosis in vivo with increasing the apple extracts. These results demonstrate the potent capacity of fresh apples to suppress DMBA-initiated mammary cancers in rats. These researches may have a significant impact on consumers' food selection and also help promote the "five-a-day" program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. These researches have a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Graybosch, R.; Liu, R.H.; Madl, R.; Shi, Y.C.; Wang, D. and Wu, X. New uses for wheat and modified wheat products. In: Wheat: Science and Trade. Carver, B., ed. Blackwell Publishing, Ames, Iowa, pp. 521-550, 2009.
  • Liu, J., Dong, H., Chen, B., Zhao, P. and Liu, R.H. Fresh apples suppress mammary carcinogenesis, proliferative activity, and induce apoptosis in the mammary tumors of the Sprague-Dawley rat. J. Agric. Food Chem. 57 (1): 297-304, 2009.
  • Liu, R.H. Phytochemicals: human disease prevention agents. McGraw-Hill Yearbook of Science & Technology 2009, McGraw-Hill, Inc. pp281-286.
  • Liu, R.H. Recent progress in antioxidant research methodology and cellular antioxidant activity of fruits. International Fruit and Vegetable Alliance, The Scientific Newsletter, 34: 2, May 2009.
  • Okarter, N. and Liu, R.H. Health benefits of whole grain phytochemicals. Critical Review in Food Science and Nutrition 2010(in press).
  • Yang, J. and Liu, R.H. Synergistic effect of apple extracts and quercetin 3--D-glucoside combination on antiproliferative activity in MCF-7 human breast cancer cells in vitro. J. Agric. Food Chem. 57 (18): 8581-8586, 2009 (Online 8/20/09).
  • Okarter, N., Liu, C-S., Sorrells, M.E., and Liu, R.H. Phytochemical content and antioxidant activity of six diverse varieties of whole wheat. Food Chemistry 119 (1): 249-257, 2009.
  • Yang, J. Martinson, T.E., and Liu, R.H. Phytochemical profiles and antioxidant activies of wine grapes. Food Chemistry 116: 332-339, 2009.
  • Yang, J. and Liu, R.H. Induction of phase II enzyme, quinone reductase, in murine hepatoma cells in vitro by grape extracts and selected phytochemicals. Food Chemistry 114 (3): 898-904, 2009.
  • Li, Q., Liu, N., Wang, Y., Zhou, L., Wu, Q., Fan, Z., Sun, J., Wang, Y., Yin, P., Zhou, S., Gao, H., Liu, R.H. Helicobacter pylori enhances cyclooxygenase-2 expression via p38MAPK/ATF-2 signaling pathway in MKN45 cells. Cancer Letters 278: 97-103, 2009.
  • Yang, J., Liu, R.H., and Halim, L. Antioxidant and antiproliferative activities of common edible nut. LWT-Food Science and Technology 42(1): 1-8, 2009.
  • Felice, D.L., Sun, J. and Liu, R.H. A modified methylene blue assay for accurate cell counting. Journal of Functional Foods 1 (1): 109-118, 2009.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Breast cancer is the most commonly diagnosed cancer in women.Increased intake of fruits and vegetables has been consistently associated with a reduced risk of cancer.Apples are one of the largest contributors of fruit phenolics of all fruits consumed by Americans and contain a variety of bioactive compounds.Consumption of apples has been linked to reduced risk of cancer.We have reported apple extracts have potent antioxidant and antiproliferative activity in vitro.However,the molecular mechanisms of the anticancer properties of apple extracts are not completely understood. We analyzed a possible mechanism by which apple extracts could inhibit cancer cell growth in vitro using estrogen-dependent MCF-7 and estrogen-independent MDA-MB-231 human breast cancer cells.Apple extracts significantly inhibited human breast cancer MCF-7 and MDA-MB-231 cell proliferation.DNA flow cytometric analysis showed that apple extracts significantly induced G1 arrest in both MCF-7 and MDA-MB-231 cells in a dose-dependent manner,but caused a greater increase in the G1/S ratio in MDA-MB-231 cells when compared to MCF-7 cells.Cyclin D1 and Cdk4 proteins,the two major G1/S transit regulators,decreased in a dose-dependent manner after exposure to apple extracts.These results suggest that the antiproliferative activities of apple extracts towards human breast cancer cells might be due to the modulation effects on cell cycle machinery. We also showed that whole apple extracts had potent anti-cancer activity in a rat mammary cancer model.Rats were given the whole apple extracts (0,3.3,10.0 or 20.0 g/kg body weight) starting 2 weeks prior to 7,12-dimethylbenz(a)anthracene (DMBA) administration and continuing for the 24 weeks.Rats treated with DMBA developed mammary tumors with 71.4% tumor incidence.No tumors were detected in the negative control group untreated with DMBA.A dose-dependent inhibition of mammary carcinogenesis by apple extracts was observed.The expression of proliferating cell nuclear antigen (PCNA),cyclin D1 and Bcl-2 decreased,and Bax expression and apoptosis increased with increasing the apple extracts. Nuclear factor-&#954;B (NF-&#954;B)is a transcription factor,which plays an important role in inflammation,cell proliferation,apoptosis,and immunity.In cancer cells,NF-&#954;B induces resistance to the anti-cancer chemotherapeutic agents by increasing cell proliferation and inhibiting apoptosis.Therefore,inhibition of NF-&#954;B activation in cancer cells is advantageous in cancer therapy by lowering the resistance to chemotherapy.We reported that apple extracts inhibited TNF-a-induced NF-&#954;B activation in MCF-7 cells. Here we reported 2a-Hydroxyursolic acid,one of the major triterpenoids isolated from apple peels,significantly inhibited MCF-7 cells proliferation.By 2a-hydroxyursolic acid treatment,phosphorylation level of NF-&#954;B inhibitor (I&#954;B-a) was not affected,but proteasome activity in MCF-7 cells was inhibited significantly.These results suggest that 2a-hydroxyursolic acid has antiproliferative activities against MCF-7 cells and capabilities inhibiting NF-&#954;B activation induced by TNF-a partially by suppressing proteasome activities. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Our results showed that whole apple extracts significantly inhibited human breast cancer MCF-7 and MDA-MB-231 cell proliferation and induced G1 arrest in a dose-dependent manner. Apple extracts decreased expression of Cyclin D1 and Cdk4 proteins in a dose-dependent manner. These results suggest that the antiproliferative activities of apple extracts towards human breast cancer cells might be due to the modulation effects on cell cycle machinery. We also showed that whole apple extracts had potent anti-cancer activity in a rat mammary cancer model. Rats treated with the carcinogen developed mammary tumors with 71% tumor incidence during a 24-week study. Application of low, middle and high doses of whole apple extracts, comparable to human consumption of 1, 3, and 6 apples per day, reduced the tumor incidence by 17, 39, and 44 percent, respectively. Apple extracts also decreased the expression of proliferating cell nuclear antigen (PCNA), cyclin D1 and Bcl-2, and increased expression of Bax and apoptosis in vivo with increasing the apple extracts. Our results suggest that 2&#945;-Hydroxyursolic acid, one of the major triterpenoids isolated from apple peels, had potent antiproliferative activity and the capabilities of inhibiting TNF-&#945;-induced NF-&#954;B activation of MCF-7 cells by inhibiting the proteasomal activities instead of I&#954;B kinase (IKK) activation. These researches help us to better understand the potential of phytochemicals from apples to prevent human cancer. These researches may have a significant impact on consumers' food selection and also help promote the "five-a-day" program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. These researches have a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Wolfe, K., Kang, X., He, X., Dong, M., Zhang, Q., and Liu, R.H. Cellular antioxidant activity of common fruits. J. Agric. Food Chem. 56 (18): 8418-8426, 2008 (Online 8/30/08).
  • Yoon, H. and Liu, R.H. Effect of 2α-hydroxyursolic acid on NF-κB activation induced by TNF-α in human breast cancer MCF-7 cells. J. Agric. Food Chem. 56 (18): 8412-8417, 2008 (Online 8/14/08).
  • Wolfe, K. and Liu, R.H. Structure-activity relationships of flavonoids in the cellular antioxidant activity assay. J. Agric. Food Chem. 56 (18): 8404-8411, 2008 (Online 8/15/08).
  • Shin, Y.J, Ryu, J.A., Liu, R.H., Nock, J.F., Polar-Cabrera, K., and Watkins, C.B. Fruit quality, antioxidant contents and activity, and antiproliperative activity of strawberry fruit stored in elevated CO2 atmospheres. J. Food Sci. 73 (6): S339-S334, 2008.
  • Sun, J. and Liu, R.H. Apple phytochemical extracts inhibited proliferation of estrogen-dependent and estrogen-independent human breast cancer cells through cell cycle modulation. J. Agric. Food Chem. 56 (24): 11661-11667, 2008 (Online 11/26/08).
  • He, X.J. and Liu, R.H. Phytochemicals of apple peels: isolation, structure elucidation, and their antiproliferative and antioxidant activities. J. Agric. Food Chem. 56 (21): 9905-9910, 2008 (Online 10/2/08).
  • He, X.J., Liu, D. and Liu, R.H. A novel sodium borohydride/chloranil-based assay for quantifying total flavonoids. J. Agric. Food Chem. 56 (20): 9337-9344, 2008 (Online 9/18/08).
  • Shin, YJ, Ryu, J-A., Liu, R.H., Nock, J.F. and Watkins, C.B. Harvest maturity, storage temperature and relative humidity affect fruit quality, antioxidant contents and activity, and inhibition of cell proliferation of strawberry fruit. Postharvest Biology and Technology 49 (2): 201-209, 2008.
  • Shin, Y.J, Nock, J.F., Liu, R.H., and Watkins, C.B. Cooling strawberries-going halfway may be enough. New York Fruit Quarterly 16(2): 9-13, 2008.
  • Liu, R.H. Cellular antioxidant activity assay for assessing antioxidant function. The 2008 annual meeting of the International Society for Nutraceuticals and Functional Foods (ISNFF), Taichung, Taiwan, November 14-17, 2008.
  • Liu, R.H. Phytochemicals for cancer prevention: mechanisms of action. The 2008 annual meeting of the International Society for Nutraceuticals and Functional Foods (ISNFF), Taichung, Taiwan, November 14-17, 2008.
  • Liu, J. R. and Liu, R. H. Apple phytochemical extracts inhibit rat mammary carcinogenesis. American Institute for Cancer Research (AICR) Annual Conference: International Research Conference on Food, Nutrition, and Cancer, Washington, DC, November 6-7, 2008.
  • Liu, R.H. Cellular antioxidant activity for assessing antioxidant function. The 14th IUFoST World Congress of Food Science and Technology, "Food for Health and Wellbeing: Tradition Meets the Future". The International Union of Food Science and Technology (IUFoST), Shanghai, P.R. China, October 19-23, 2008.
  • Liu, R.H. Phytochemicals for Cancer Prevention: Mechanisms of Action. The 14th IUFoST World Congress of Food Science and Technology, "Food for Health and Wellbeing: Tradition Meets the Future". The International Union of Food Science and Technology (IUFoST), Shanghai, P.R. China, October 19-23, 2008.
  • Liu, R.H. Health Benefits of Whole Grain Phytochemicals. The 2008 AACC International Meeting, September 21-24, 2008, Honolulu, Hawaii.
  • Liu, R.H. Dietary Phytochemicals and Health Benefits: "Food for Thought". The 6th International Phytochemicals Symposium, Korean Society of Food Science and Technology (KoSFoST), Seoul, South Korea, September 18, 2008.
  • Liu, R.H. Cellular antioxidant activity of common fruits and selected phytochemicals. Symposium of Division of Agricultural and Food Chemistry: Flavor Chemistry and Health Benefit of Small Fruits. The 236th American Chemical Society (ACS) National Meeting & Exposition, Philadelphia, PA, August 17-21, 2008.
  • Liu, R.H. Moving toward cell-based antioxidant activity assay for assessing antioxidant function. Nutrition Division Symposium: Nutrition Controversies: Moving beyond lab chemical methods for antioxidant assessment as related to health benefits. Institute of Food Technologists, IFT 2008 Annual Meeting, New Orleans, LA, June 28-July 1, 2008.
  • Liu, R. H. Health Benefits of whole grain phytochemicals: opportunities and challenges for food industry. Nutrition Division Symposium: Designing and Delivering Whole Grains with Enhanced Health Attributes. Institute of Food Technologists, IFT 2008 Annual Meeting, New Orleans, LA, June 28-July 1, 2008.
  • Liu, J. R. and Liu, R. H. Apple phytochemical extracts inhibit cell proliferation and induce apoptosis in vivo in a rat model for mammary carcinogenesis. Institute of Food Technologists, IFT 2008 Annual Meeting, New Orleans, LA, June 28-July 1, 2008.
  • Wolfe, K. L. and Liu, R.H. Structure-activity relationships of flavonoids in the cellular antioxidant activity assay. Institute of Food Technologists, IFT 2008 Annual Meeting, New Orleans, LA, June 28-July 1, 2008.
  • Okarter, N., Liu, C.-S., Sorrells, M. E. and Liu, R. H. Phytochemical profiles and antioxidant activity of whole wheat. Institute of Food Technologists, IFT 2008 Annual Meeting, New Orleans, LA, June 28-July 1, 2008.
  • Vayndorf, E. and Liu, R. H. Effects of Apple Phytochemical Extracts and Selected Phytochemicals on Healthspan and Lifespan in Caenorhabditis elegans. American Aging Association -37th Annual Meeting: The Role of Genes, Environment and Chance in Determining Aging, Boulder, Colorado, May 30 - June 2, 2008.
  • Felice, D.L., Sun, J. and Liu, R.H. A modified methylene blue assay for accurate cell counting. Journal of Functional Foods 1 (1): 109-118, 2009 (Online 10/19/08).
  • Liu, J., Dong, H., Chen, B., Zhao, P. and Liu, R.H. Fresh apples suppress mammary carcinogenesis, proliferative activity, and induce apoptosis in the mammary tumors of the Sprague-Dawley rat. J. Agric. Food Chem. 57: 2009 (Online 12/10/08).
  • Liu, R.H. Phytochemicals: Human disease prevention agents. McGraw-Hill Yearbook of Science & Technology 2009. McGraw-Hill, Inc. December 22, 2008.


Progress 10/01/06 to 09/30/07

Outputs
Breast cancer is the most commonly diagnosed cancer in women. Epidemiological studies have suggested the inverse association between cancer risk and intake of fruits and vegetables. Work performed by our group and others have shown that fruit and vegetable phytochemical extracts exhibit strong antioxidant and antiproliferative activities. Nuclear factor-&#954;B (NF-&#954;B) is a transcription factor, which plays an important role in inflammation, cell proliferation, apoptosis, and immunity in eukaryotes. In cancer cells, NF-&#954;B induces resistance to the anti-cancer chemotherapeutic agents by increasing cell proliferation and inhibiting apoptosis. Therefore, inhibition of NF-&#954;B activation in cancer cells is advantageous in cancer therapy by lowing the resistance to chemotherapy. Several phytochemicals from fruits and vegetables have been reported to inhibit the NF-&#954;B activation and the mechanisms how the phytochemicals work have not been fully understood. We examined effects of selected phytochemicals and apple extracts on TNF-&#945;-induced NF-&#954;B activation in human breast cancer MCF-7 cells. Apple extracts significantly inhibited the TNF-&#945;-induced NF-&#954;B activation. Curcumin also significantly blocked the TNF-&#945;-induced NF-&#954;B activation. Both apple extracts and curcumin, did not affect phosphorylation of inhibitor of NF-&#954;B-&#945; (I&#954;B-&#945;), but significantly inhibited proteasomal activity of MCF-7 cells. Our results suggest that apple extracts and curcumin have the capabilities of inhibiting TNF-&#945;-induced NF-&#954;B activation of MCF-7 cells by inhibiting the proteasomal activities. We have isolated phytochemical compounds from apple peels using bioactivity-guided fractionation. Their chemical structures were identified using HR-MS, 1D and 2D NMR, and X-ray diffraction analysis. Antiproliferative activities of isolated triterpenoids against HepG2 liver cancer cells, MCF-7 breast cancer cells, and Caco-2 colon cancer cells were evaluated. Most of the triterpenoids showed high potential anticancer activities against the three human cancer cell lines. Among the compounds isolated, 2&#945;-hydroxyl ursolic acid, 2&#945;-hydroxy-3&#946;-{[(2E)-3-phenyl-1-oxo-2-propenyl]oxy}-olean-1 2-en-28-oic acid and 3&#946;-trans-p-coumaroyloxy-2&#945;-hydroxy-olean-12-en-28-oic acid showed higher antiproliferative activity toward HepG2 cancer cells. Ursolic acid, 2&#945;-hydroxyl ursolic acid and 3&#946;-trans-p-coumaroyloxy-2&#945;-hydroxy-olean-12-en-28-oic acid exhibited higher antiproliferative activity against MCF-7 cancer cells. All triterpenoids tested showed antiproliferative activity against Caco-2 cancer cells, especially 2&#945;-hydroxyl ursolic acid, maslinic acid, 2&#945;-hydroxy-3&#946;-{[(2E)-3-phenyl-1-oxo-2-propenyl]oxy}-olean-1 2-en-28-oic acid and 3&#946;-trans-p-coumaroyloxy-2&#945;-hydroxy-olean-12-en-28-oic acid displaying much higher antiproliferative activity. These results showed the triterpenoids isolated from apple peels have potent antiproliferative activity and may be partially responsible for the anticancer activities of whole apples.

Impacts
Our results suggest that apple extracts and selected phytochemicals have the capabilities of inhibiting TNF-&#945;-induced NF-&#954;B activation of MCF-7 cells by inhibiting the proteasomal activities instead of I&#954;B kinase (IKK) activation. Our research also demonstrated the triterpenoids isolated from apple peels have potent antiproliferative activity and may be partially responsible for the anticancer activities of whole apples. These researches help us to better understand the potential of phytochemicals from apples to prevent human cancer We recently developed a new cellular antioxidant activity (CAA) assay for assessing antioxidants, foods, and dietary supplements. Many in vitro antioxidant assays are currently in wide use including ORAC, TRAP, FRAP, DPPH and TEAC, yet none of them takes into account the bioavailability/uptake and metabolism of the antioxidants. The CAA assay is a more biologically relevant method than the popular chemistry antioxidant activity assays, and is the first movement in the antioxidant field away from in vitro assays and toward cell-based antioxidant activity assay. These researches may have a significant impact on consumers' food selection and also help promote the "five-a-day" program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. These researches have a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Liu, R.H. 2007. Whole grain phytochemicals and health. Journal of Cereal Science 46 (3): 207-219(Online 7/3/07).
  • Dong, M., He, X.J. and Liu, R.H. 2007. Phytochemicals of black bean seed coats: isolation, structure elucidation, and their antiproliferative and antioxidative activities. J. Agric. Food Chem. 55 (15): 6044-6051 (Online 6/30/07).
  • He, X.J. and Liu, R.H. 2007. Triterpenoids isolated from apple peels have potent antiproliferative activity and may be partially responsible for apple's anticancer activity. J. Agric. Food Chem. 55 (11): 4366-4370 (Online 5/8/07).
  • Shin, YJ, Liu, R.H., and Watkins, C.B. 2007. Temperature and relative humidity effects on quality, total ascorbic acid, phenolics and flavonoid concentrations, and antioxidant activity of strawberry. Postharvest Biology and Technology 45: 349-357 (Online 5/3/07).
  • de la Parra, C., Serna Saldivar, S.O. and Liu, R.H. 2007. Effect of processing on the phytochemical profiles and antioxidant activity of corn for production of masa, tortilla and tortilla chips. J. Agric. Food Chem. 55 (10): 4177-4183 (Online 4/25/07).
  • Wolfe, K.L. and Liu, R.H. 2007. Cellular antioxidant activity (CAA) assay for assessing antioxidants, foods, and dietary supplements. J. Agric. Food Chem. 55 (22): 8896-8907 (Online 9/29/07).
  • Liu, R.H. 2007. The potential health benefits of phytochemicals in berry fruits in protecting against cancer and coronary heart disease. In: Berry Fruit: Value-Added Products for Health Promotion. Zhao, Y. ed., Taylor and Francis Group, LLC Boca Raton, FL.
  • Liu, R.H. and Adom, K.K. 2007. Whole grain phytochemicals and antioxidant activity. In: Whole Grains and Health. Marquart, L., Jacobs, D.R., McIntosh, G.H., Poutanen, K and Reicks, M.. Blackwell Publishing, Ames, Iowa, pp. 185-208.
  • Liu, R.H. 2007. Cell culture models for antioxidant research. The Second International Symposium on Human Health Effects of Fruits and Vegetables, Houston, Texas, October 9-13.
  • Liu, R.H. 2007. Fruit phytochemicals for cancer prevention: mechanisms of action. The Second International Symposium on Human Health Effects of Fruits and Vegetables, Houston, Texas, October 9-13.
  • Liu, R.H. 2007. Prevention of cancer with fruit phytochemicals. Symposium of Division of Agricultural and Food Chemistry: Food Bioactives and Nutraceuticals. The 234th American Chemical Society National Meeting, Boston, MA, August 19-23.
  • Liu, R.H. 2007. Cranberry phytochemicals: isolation, structure elucidation, and their anticancer activity. Symposium of Division of Agricultural and Food Chemistry: Food Bioactives and Nutraceuticals. The 234th American Chemical Society National Meeting, Boston, MA, August 19-23.
  • Liu, R.H. 2007. Cell culture models to assess bioactivity of functional foods and dietary supplements. ACS Symposium Series 956: 83-91.
  • Liu, R.H. and Felice, D.L. 2007. Whole food phytochemicals for cancer prevention. ACS Symposium Series 956: 15-34.
  • Yoon, H. and Liu, R.H. 2007. Effect of selected phytochemicals and apple extracts on NF-κB activation in human breast cancer MCF-7 cells. J. Agric. Food Chem. 55 (8): 3167-3173 (Online 3/21/07).
  • Marquart, L., Faubion, J., Liu, R.H., Smail, V., Fulcher, G. and Scheideman, M. 2007. Moving whole grains forward: The case for a whole grain collaborative. 52 (4): 196-200.
  • Liu, J. R. and Liu, R. H. 2007. Cranberries inhibit rat mammary carcinogenesis. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Liu, R.H. 2007. Characterization of flavonoids: effects of structures on the analysis, bioavailability and bioactivity. Symposium of Division of Agricultural and Food Chemistry: Flavonoids. The 234th American Chemical Society National Meeting, Boston, MA, August 19-23.
  • Liu, R.H. 2007. Health benefits of fruits and vegetables: opportunities and challenges for functional drinks. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Liu, R.H. 2007. Updated research on cranberry. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Yang, J. and R.H. Liu. 2007. Combination effect of apple extracts and quercetin 3--D-glucoside on antiproliferative activity in MCF-7 human breast cancer cells in vitro. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Liu, C-S, de la Parra, C., Serna-Saldivar, S.O. and Liu, R.H. 2007. Effect of lime-cooking, baking and frying on carotenoid uptake from corn products by Caco-2 human intestinal cells coupled with an in vitro digestion. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Yoon, H., He, X. and Liu, R. H. 2007. Effect of 2-hydroxyursolic acid on NF-κB activation in human MCF-7 breast cancer cells. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • He. X., and Liu, R.H. 2007. Triterpenoids Isolated from Apple Peels Have Potent Antiproliferative Activity and May be Responsible for Apple's Anticancer Activity. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Dong, M., He. X., and Liu, R.H. 2007. Isolation and Structure Elucidation of Bioactive Compounds in Black Bean Seed Coats. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Felice, D. L. and Liu, R.H. 2007. Comparison of whole apple extracts and purified phytochemicals: effects on proliferation of MCF-7 human breast cancer cells. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Petrofsky, K.E., Evenson, K.A., Fulcher, R.G., Liu, R.H. and Marquart, L. 2007. Processing effects on the antioxidant activity of amaranth. Institute of Food Technologists, IFT 2007 Annual Meeting, Chicago, Illinois, July 28-August 1.
  • Liu, R.H. 2007. Apple phytochemicals in the prevention of cancer: mechanisms of action. Symposium of Division of Agricultural and Food Chemistry: Natural Products, Diets and Cancer Prevention. The 233rd American Chemical Society National Meeting, Chicago, Illinois, March 25-29.


Progress 01/01/06 to 12/31/06

Outputs
Breast cancer is the most commonly diagnosed cancer in women in the U.S. and is one of the leading causes of death due to cancer. Epidemiological studies have consistently suggested the inverse association between cancer risk and intake of fruits and vegetables. Work performed by our group and others have shown that fruit and vegetable phytochemical extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. Cranberries have been shown to possess anti-carcinogenic activities such as inhibition growth of several cancer cell lines, and inhibitiion of ornithine decarboxylase (ODC) activity in vitro. However, the molecular mechanisms of the anticancer properties of cranberry phytochemical extracts have not been completely understood. Our found that cranberry phytochemical extracts significantly inhibited human breast cancer MCF-7 cell proliferation at doses of 5 to 30 mg/mL (p less than 0.05). Apoptotic induction in MCF-7 cells was observed in a dose-dependent manner after exposure to cranberry phytochemical extracts. Cranberry phytochemical extracts at doses from 10 to 50 mg/mL significantly arrested MCF-7 cells at G0/G1 phase (p less than 0.05). After 24-hour exposure to cranberry extracts, the G1/S index of MCF-7 cells was approximately 6 times higher than that of the control group (p less than 0.05). These results suggest that cranberry phytochemical extracts possess the ability to suppress the proliferation of human breast cancer MCF-7 cells and this suppression is at least partly attributed to both the initiation of apoptosis and the G1 phase arrest. We have isolated 20 phytochemical compounds from cranberries using bioactivity-guided fractionation, silica gel and ODS columns, and preparative RP-HPLC. Their chemical structures were identified using HR-MS, 1D and 2D NMR, and X-ray diffraction analysis. Antiproliferative activities of isolated compounds against HepG2 liver cancer and MCF-7 breast cancer cells were evaluated. Among the compounds isolated, ursolic acid, quercetin, and 3,5,7,3',4'-pentahydroxy-flavonol-3-O-&#946;-D-glucopyranoside showed potent antiproliferative activities against HepG2 cell growth, with EC50 values of 87.4, 40.9, and 49.2 &#956;M, respectively. Ursolic acid, quercetin, and 3,5,7,3',4'-pentahydroxy-flavonol-3-O-&#946;-D-glucopyranoside showed potent inhibitory activity toward the proliferation of MCF-7 cells, with EC50 values of 11.7, 137.5, and 23.9 &#956;M, respectively. Quercetin, 3,5,7,3',4'-pentahydroxy-flavonol-3-O-&#946;-D-glucopyranoside, 3,5,7,3',4'-pentahydroxy-flavonol-3-O-&#946;-D-galactopyranoside, and 3, 5, 7, 3',4'-pentahydroxy-flavonol-3-O-&#945;-L-arabinofuranoside) showed potent antioxidant activities, with EC50 values approximately 10 &#956;M. These results showed cranberry phytochemical extracts have potent antioxidant and antiproliferative activities

Impacts
This research may have a significant impact on consumers' food product selection and also help promote the 'five-a-day' program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. This research has a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Liu, R.H. 2006. Health benefits of phytochemicals in whole foods. In: Nutritional Health: Strategies for Disease Prevention. Second Edition. Wilson, T., Temple N.J., and Jacob, D.R., eds. Human Press inc., Totowa, New Jersey, pp.173-188.
  • Liu, R.H. 2006. Natural Products for Cancer Prevention. WORLDNUTRA, Reno, NV, November 6, 2006.
  • He, X.J. and Liu, R.H. 2006. Cranberry phytochemicals: isolation, structure elucidation, and their antiproliferative and antioxidant activities. J. Agric. Food Chem. 54 (19): 7069-7074.
  • Sun, J. and Liu, R.H. 2006. Cranberry phytochemical extracts induce cell cycle arrest and apoptosis in human MCF-7 breast cancer cells. Cancer Letters 241: 124-134.
  • He, X.J., Tang, J. Qiao, A.M., Wang, G.H., Jiang, M., Liu, R.H., and Yao, X.S. 2006. Cytotoxic biotransformed products from cinobufagin by Mucor spinosus and Aspergillus niger. Steroids 71 (5): 392-402.
  • Shin, YJ, Nock, J.F., Liu, R.H., and Watkins, C.B. 2006. Storage temperature and relative humidity effects on quality and antioxidant composition of strawberry fruit. Hortscience 41 (3): 493-493.
  • He, X., Lobkovsky, E., and Liu, R.H. 2006. (2S*,3S*,4R*,5R*)-3,4,5-Trihydroxy-6-(hydroxymethyl)-3,4,5,6-tetrahyd ro-2H-pyran-2-yl benzoate. Acta Cryst. E62: O471-O472.
  • He, X.J., Qiao, A.M., Liu, B., Wang, X.L., Wang, G.H., Qu, G.X., Liu, R.H., and Yao, X.S. 2006. Bioconversion of methyl protodioscin by Penicillium melinii cells. Enzyme and Microbial Technology 38 (3-4): 400-406.
  • Liu, R.H. 2006. Health benefits of natural antioxidants: implications for cardiovascular disease prevention. WORLDNUTRA, Reno, NV November 5, 2006.
  • Liu, R.H. 2006. Potential Synergy of Phytochemicals in Cancer Prevention: Mechanism of Action. Cornell University/ Shanghai Jiao Tong University (SJTU) 2nd International. 2006


Progress 01/01/05 to 12/31/05

Outputs
Epidemiological studies have consistently shown that regular consumption of fruit and vegetables is strongly associated with reduced risk of developing chronic diseases, such as cancer and cardiovascular disease. Work performed by our group and others have shown that fruit and vegetable phytochemical extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. Apples are commonly consumed and are the major contributors of phytochemicals in human diets. We found that apple extracts exhibit strong antioxidant and antiproliferative activities, and that the major part of total antioxidant activity is from the combination of phytochemicals. Phytochemicals, including phenolics and flavonoids, are suggested to be the bioactive compounds contributing to the health benefits of apples. We also found that whole apple extracts prevented mammary cancer in a rat model in a dose dependent manner at the doses comparable to human consumption of 1, 3, and 6 apples a day. This study demonstrated that whole apple extracts effectively inhibited mammary cancer growth in the rat model, thus consumption of apples may be an effective strategy for cancer protection. We found that cranberry phytochemical extracts significantly inhibited human breast cancer MCF-7 cell proliferation at doses of 5 to 30 mg/mL. Apoptotic induction in MCF-7 cells was observed in a dose-dependent manner after exposure to cranberry phytochemical extracts. Cranberry phytochemical extracts at doses from 10 to 50 mg/mL significantly arrested MCF-7 cells at G0/G1 phase. A constant increasing pattern of the G1/S index was observed in the cranberry extract treatment group while the G1/S ratio of the control group decreased concomitantly between 10 and 24 hour treatment. After 24-hour exposure to cranberry extracts, the G1/S index of MCF-7 cells was approximately 6 times higher than that of the control group. These results suggest that cranberry phytochemical extracts possess the ability to suppress the proliferation of human breast cancer MCF-7 cells and this suppression is at least partly attributed to both the initiation of apoptosis and the G1 phase arrest. Cranberry extracts were found to have potent antioxidant capacity preventing in vitro LDL oxidation with increasing delay and suppression of LDL oxidation in a dose-dependent manner. The antioxidant activity of 100 g cranberries against LDL oxidation was equivalent to 1000 mg vitamin C or 3700 mg vitamin E. Cranberry extracts also significantly induced expression of hepatic LDL receptors and increased intracellular uptake of cholesterol in HepG2 cells in vitro in a dose-dependent manner. This suggests that cranberries could enhance clearance of excessive plasma cholesterol in circulation. We propose that additive or synergistic effects of phytochemicals in cranberries are responsible for the inhibition of LDL oxidation, the induced expression of LDL receptors, and the increased uptake of cholesterol in hepatocytes.

Impacts
This research may have a significant impact on consumers food product selection and also help promote the five-a-day program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. This research has a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • He, X., Lobkovsky, E., and Liu, R.H. 2006. Benzoic Acid beta-D-Glucopyranoside. Acta Crystallographica E61:, 2005. (2S*,3S*,4R*,5R*)-3,4,5-Trihydroxy-6-(hydroxymethyl)-3,4,5,6-tetrahyd ro-2H-pyran-2-yl benzoate. Acta Cryst. E62: O471-O472.
  • Sun, J. and Liu, R.H. 2005. Cranberry phytochemical extracts induce cell cycle arrest and apoptosis in human MCF-7 breast cancer cells. Cancer Letters, (published on line 12/27/05).
  • He, X.J., Lobkovsky, E., and Liu, R.H. 2005. (R*)-Methyl 3-carboxy-2-hydroxypropanoate. Acta Cryst. E61: O4104-O4106.
  • Adom, K.K. and Liu, R.H. 2005. A rapid peroxylradical scavenging capacity (PSC) assay for assessing both hydrophilic and lipophilic antioxidants. J. Agric. Food Chem. 53 (17): 6572-6580.
  • Chu, Y-F., and Liu, R.H. 2005. Cranberries inhibit LDL oxidation and induce LDL receptor expression in hepatocytes. Life Science 77 (15): 1892-1901.
  • Liu, R.H. and Finely, J. 2005. Potential cell culture models for antioxidant research. J. Agric. Food Chem. 53 (10): 4311-4314.
  • Liu, R.H., Liu, J., and Chen, B. 2005. Apples prevent mammary tumors in rats. J. Agric. Food Chem. 53:2341-2343.
  • Adom, K.K., Sorrells, M.E., and Liu, R.H. 2005. Phytochemicals and antioxidant activity of milled fractions of different wheat varieties. J. Agric. Food Chem. 53: 2297-2306.
  • Boyer, J., Brown, D., and Liu, R.H. 2005. In vitro digestion and lactase treatment influence uptake of quercetin and quercetin glucoside by the Caco-2 cell monolayer. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Chu, Y.-F. and Liu, R.H. 2005. Apple phytochemicals inhibit human LDL oxidation and induce hepatic LDL receptor expression. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Liu, C S. and Liu, R.H. Investigation of factors affecting the bioavailability of carotenoids in whole foods by a Caco-2 cell culture model coupled with an in vitro digestion. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Liu, J. and Liu, R.H. 2005. beta-Ionone inhibits rat mammary carcinogenesis. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Sun, J. and Liu, R.H. 2005. Inhibition of cranberry extracts on cyclooxygenase-2 expression and activity in human pharyngeal cancer cells. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Yang, J., Halim, L., and Liu, R.H. 2005. Antioxidant and antiproliferative activities of common nuts. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Liu, R.H. 2005. Phytochemicals in Cancer Prevention: Mechanism of Action. Symposium of Division of Agricultural and Food Chemistry: Chemistry and Biochemistry of Antioxidative Phytochemicals. PACIFICHEM 2005, Honolulu, Hawaii, December 15-20, 2005.
  • Liu, R.H. 2005. Potential Role of Phytochemicals in Cardiovascular Disease Prevention. Symposium of Division of Agricultural and Food Chemistry: Chemistry and Biochemistry of Antioxidative Phytochemicals. PACIFICHEM 2005, Honolulu, Hawaii, December 15-20, 2005.
  • Liu, R.H. 2005. Potential role of phytochemicals in cancer prevention: Mechanisms of action. Symposium of Division of Agricultural and Food Chemistry: The Potential Health Benefits of Antioxidants. The 230th American Chemical Society National Meeting, Washington, D.C., August 28-September 1, 2005.
  • Adom, K.K. and Liu, R.H. 2005. A rapid peroxylradical scavenging capacity (PSC) assay for assessing both hydrophilic and lipophilic antioxidants. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.
  • Yoon, H. and Liu, R. H. 2005. Effect of selected phytochemicals and apple extracts on PARP activity in oxidatively-stressed MCF-7 breast cancer cells. IFT 2005 Annual Meeting, New Orleans, LA, July 16-20, 2005.


Progress 01/01/04 to 12/31/04

Outputs
Epidemiological studies have consistently shown that regular consumption of fruit and vegetables is strongly associated with reduced risk of developing chronic diseases, such as cancer and cardiovascular disease. Work performed by our group and others have shown that fruit and vegetable phytochemical extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. We proposed that the additive and synergistic effects of phytochemicals in fruit and vegetables are responsible for these potent antioxidant and anticancer activities and that the benefit of a diet rich in fruit and vegetables is attributed to the complex mixture of phytochemicals present in whole foods. This explains why no single antioxidant can replace the combination of natural phytochemicals in fruit and vegetables to achieve the health benefits. The evidence suggests that antioxidants or bioactive compounds are best acquired through whole food consumption, not from expensive dietary supplements. We believe that a recommendation that consumers to eat a wide variety of fruits and vegetables daily is an appropriate strategy for significantly reducing the risk of chronic diseases and to meet their nutrient requirements for optimum health. Quercetin and quercetin glycosides are widely consumed flavonoids found in many fruits and vegetables. These compounds have a wide range of potential health benefits, and understanding the bioavailability of flavonoids from foods is becoming increasingly important. We combined an in vitro digestion, a lactase treatment and the Caco-2 cell model to examine quercetin and quercetin glucoside uptake from shallot and apple homogenates. The in vitro digestion alone significantly decreased quercetin aglycone recovery from the shallot digestate (p less than 0.05), but had no significant effect on quercetin-3-glucoside recovery (p greater than 0.05). Digestion increased the Caco-2 cell uptake of shallot quercetin-4-glucoside by 2-fold when compared to the non-digested shallot. Despite the loss of quercetin from the digested shallot, the bioavailability of quercetin aglycone to the Caco-2 cells was the same in both the digested and non-digested shallot. Treatment with lactase increased quercetin recovery from the shallot digestate nearly 10-fold and decreased quercetin-4-glucoside recovery by more than 100-fold (p less than 0.05), but had no effect on quercetin recovery from apple digestates. Lactase treatment also increased shallot quercetin bioavailability to the Caco-2 cells approximately 14-fold, and decreased shallot quercetin-4-glucoside bioavailability 23-fold (p less than 0.05). These Caco-2 cells had lactase activity similar to that expressed by a lactose intolerant human. The increase in quercetin uptake following treatment with lactase suggests that dietary supplementation with lactase may increase quercetin bioavailability in lactose intolerant humans. Combining the digestion, the lactase treatment and the Caco-2 cell culture model may provide a reliable in vitro model for examining flavonoid glucoside bioavailability from foods.

Impacts
This research may have a significant impact on consumers food product selection and also help promote the five-a-day program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. This research has a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Liu, R.H. 2004. Potential synergy of phytochemicals in cancer prevention: mechanism of action. J. Nutr. 134: 3479S-3485S.
  • Boyer, J., Brown, D., and Liu, R.H.. 2004. Uptake of quercetin and quercetin-3-glucoside from whole onions and apple peels by Caco-2 cell monolayers. J. Agric. Food Chem. 52 (23): 7172-7179.
  • Chu, Y-F. and Liu, R. H. 2004. Novel low-density lipoprotein (LDL) oxidation model: Antioxidant capacity for the inhibition of LDL. J. Agric. Food Chem. 52 (22): 6818-6823.
  • Yang, J., Meyers, K.J., van der Heide, J. and Liu, R.H. 2004. Varietal differences in phenolic content, and antioxidant and antiproliferative activities of onions. J. Agric. Food Chem. 52 (22): 6787-6793.
  • Liu, C-S, Glahn, R. P., and Liu. R.H. 2004. Assessment of carotenoid bioavailability of whole foods using a Caco-2 cell culture model coupled with an in vitro digestion. J. Agric. Food Chem. 52: 4330-4337.
  • Boyer, J. and Liu, R.H. 2004. Apple phytochemicals and their health benefits. Nutrition Journal 3:5.
  • Adom, K.K., Sorrells, M.E., and Liu, R.H. 2005. Phytochemicals and antioxidant activity of milled fractions of different wheat varieties. J. Agric. Food Chem.
  • Boyer, J., Brown, D., and Liu, R.H. 2005. In vitro digestion and lactase treatment influence uptake of quercetin and quercetin glucoside by the Caco-2 cell monolayer. Nutritional Journal 4:1.


Progress 01/01/03 to 12/31/03

Outputs
It has been recently reported that the inhibition of cancer cell proliferation by fruit extracts was indirectly caused by phenolic-induced H2O2 production in the cell culture media suggesting that many previously reported effects of flavonoids and phenolic compounds on cultured cells might be from an artifact of H2O2-induced oxidative stress. We conducted a study to determine if apple extracts induced H2O2 formation in common cell culture media, and to investigate if the antiproliferative activity of apple extracts was due to phenolic-induced H2O2 formation. We found that apple extracts did not induce H2O2 formation in WME, DMEM, and DMEM/Ham F12 media with the cell culture conditions tested. Antiproliferative activity of apple extracts was not due to the phenolic-induced H2O2 production in cell culture media. In addition, H2O2 added to the culture medium at 100 mM did not cause inhibition of cell proliferation in HepG2 liver cancer cells in vitro. These data confirm our original conclusion that apple extracts exhibit strong antiproliferative activity. This activity could be due to the inherent combination and complex interaction of phytochemicals in apples, but is not due to phenolic-induced H2O2 production. Cell proliferation assays have been successfully used to screen anticancer compounds in conjunction with cytotoxicity assays and will continue to serve as an important model for initial anticancer drug screening from natural products. Apple peels have high concentrations of phenolic compounds and may assist in the prevention of chronic diseases. Millions of pounds of waste apple peels are generated in the production of applesauce and canned apples in New York State each year. We proposed that a valuable food ingredient could be made using the peels of these apples if they could be dried and ground to a powder without large losses of phytochemicals. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production were investigated. Within each variety, the total phenolic content was highest in the peels, followed by the flesh + peel and the flesh. The peels all had significantly higher total antioxidant activities than the flesh + peel and flesh of the apple varieties examined. Idared peels had the greatest antioxidant activity. Apple peels were also shown to more effectively inhibit the growth of HepG2 human liver cancer cells than the other apple components. The high content of phenolic compounds, antioxidant activity, and antiproliferative activity of apple peels indicate that they may impart health benefits when consumed, and should be regarded as a valuable source of antioxidants. We developed a process to produce apple peel powder with high phytochemical content and antioxidant activity. Apple peel powder may be used in a various food products to add phytochemicals and promote good health.

Impacts
This research may have a significant impact on consumers food product selection and also help promote the "five-a-day" program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. This research has a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Adom, K.K., Sorrells, M.E., and Liu, R.H. 2003. Phytochemicals and antioxidant activity of wheat varieties. J. Agric. Food Chem. 51 (26): 7825-7834.
  • Meyers, K.K., Watkins, C.B., Pritts, M.P., and Liu, R.H. 2003. Antioxidant and antiproliferative activities of strawberries. J. Agric. Food Chem. 51 (23): 6887-6892.
  • Liu, R.H. 2003. Health benefits of fruits and vegetables are from additive and synergistic combination of phytochemicals. Am. J. Clin. Nutr. 78: 517S-520S.
  • Liu, R.H. 2004. Health Benefits of Fruits, Vegetables and Whole Grains: Mechanism of Action. Nutrition Division Symposium: An Update on Antioxidants in Fruits, Vegetables and Whole Grains. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Liu, R.H. 2003. Protective role of phytochemicals in whole foods: Implications for chronic disease prevention. Applied Biotechnology, Food Science and Policy 1(1): 39-46.
  • Wolfe, K. and Liu, R.H. 2003. Apple peels as a value-added food ingredient. J. Agric. Food Chem. 51 (6): 1676-1683.
  • Liu, R.H. and Sun, J. 2003. Antiproliferative activity of apples is not due to phenolic-induced hydrogen peroxide formation. J. Agric. Food Chem. 51 (6): 1718-1723.
  • Yeung , C.K., Glahn, R.P., Wu, X., Liu, R.H., and Miller, D.D. 2003. Iron bioavailability and antioxidant activity of raisins. J Food Sci 65 (2): 701-705.
  • Wolfe, K., Wu, X., and Liu, R.H. 2003. Antioxidant activity of apple peels. J. Agric. Food Chem. 51 (3): 609-614.
  • Boyer, J. and Liu, R.H. 2003. Antioxidants of apples. New York Fruit Quarterly 11(4): 11-15.
  • Liu, R.H. and Wolfe, K.L. 2003. Role of plant-based whole foods in the prevention of chronic diseases. Foods & Food Ingredients Journal of Japan. 208 (6): 465-490.
  • Liu, R.H. 2004. Effects of processing on the antioxidant activity and phytochemical bioavailability in fruits and vegetables. Fruit and Vegetable Products Division Symposium: Practical Applications of Antioxidant Measurements for Fresh and Processed Fruits and Vegetables. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Chu, Y-F and Liu, R.H. 2004. A novel LDL oxidation model: antioxidant capacity for the inhibition of LDL oxidation. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Boyer, J., Brown, D. and Liu, R.H. 2004. Assessment of quercetin and quercetin-3-glucoside bioavailability from onions and apple peels using Caco-2 cell model. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Liu, C-S., Liu, R.H. 2004. Assessment of carotenoid bioavailability of whole foods using a Caco-2 cell culture model coupled with an in vitro digestion. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Adom, K.K., Sorrells, M.E., and Liu, R.H. 2004. Phytochemical profiles of milled fractions of wheat varieties. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Sun J., Felice, D.L., and Liu, R.H. 2004. Effects of cranberry extracts on cell growth and apoptosis in human MCF-7 breast cancer cells. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Yang, J. and Liu, R.H. 2004. Varietal differences in phenolic content, and antioxidant and antiproliferative activities of onions. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Kaur, R., Savage, G.P., Lister, C.E. and Liu, R.H. 2004. Antioxidant activity in different fractions of commercially grown New Zealand tomatoes. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Saldivar S.O.S., Gutierrez-Uribe, J.A. and Liu, R.H. 2004. Effect of black bean (Phaseolus vulgaris) phytochemical extracts on the inhibition of Caco-2 human colon cancer cells. IFT 2004 Annual Meeting, Las Vegas, Nevada, July 12-16, 2004.
  • Liu, R.H. 2003. Health benefits of phytochemicals of fruits and vegetables. American Aging Association Meeting: Nutritional Modulation of Aging and Age-Related Diseases, Baltimore, MD, June 7-9, 2003
  • Wolfe, K.L. and Liu, R.H. 2003. Apple peel powder a potential value-added food ingredient for functional foods. Institute of Food Technologists, IFT Annual Meeting, Chicago, IL, July 12-16, 2003.
  • Sun, J. and Liu, R.H. 2003. Antiproliferative activity of apples. Institute of Food Technologists, IFT Annual Meeting, Chicago, IL, July 12-16, 2003.
  • Adom, K.K., Sorrells. M. and Liu, R.H. 2003. Phytochemical profiles and total antioxidant activity of wheat varieties. Institute of Food Technologists, IFT Annual Meeting, Chicago, IL, July 12-16, 2003.


Progress 01/01/02 to 12/31/02

Outputs
Our laboratory reported that phytochemical extracts from apples, grapes, cranberries, and raspberries have strong antioxidant and anticancer activities, and that the major part of total antioxidant activity is from the combination of phytochemicals. Our found that the combination of phytochemicals in apples is critical to its potent antioxidant activity and antiproliferative activity. We also found that the phytochemicals in raspberries may have a significant affect on antioxidant and anticancer activity. Raspberries higher in phenolic and flavonoid compounds have higher antioxidant activity. The darker colored raspberry varieties showed greater antioxidant activity than the lighter colored variety. The antioxidant activity of the raspberry was directly related to the total amount of phenolics and flavonoids found in the raspberry, but there was no relationship between antiproliferative activity and the total amount of phenolics/flavonoids found in the same raspberry. The inhibition of cancer cell proliferation is attributed to some unknown compound(s) present in raspberry fruits. During applesauce and canned apple manufacture, the antioxidant-rich peels of apples are discarded. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production were investigated. Within each variety, the total phenolic content was highest in the peels, followed by the flesh + peel and the flesh. Idared and Rome Beauty apple peels had the highest total phenolic contents. Of the four varieties, Idared apple peels had the most anthocyanins. The peels all had significantly higher total antioxidant activities than the flesh + peel and flesh of the apple varieties examined. Idared peels had the greatest antioxidant activity. Apple peels were also shown to more effectively inhibit the growth of HepG2 human liver cancer cells than the other apple components. The high content of phenolic compounds, antioxidant activity, and antiproliferative activity of apple peels indicate that they may impart health benefits when consumed, and should be regarded as a valuable source of antioxidants.

Impacts
This research may have a significant impact on consumers' food product selection and also help promote the ''five-a-day'' program increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. This research has a critical economic impact on NY State and US fruit and vegetable growers and fruits industry.

Publications

  • Liu, R.H. 2002. Health benefits of fruits and vegetables are from additive and synergistic combination of phytochemicals. Fourth International Congress for Vegetarian Nutrition, Loma Linda University, Loma Linda, CA, April 8-11, 2002.
  • Yeung , C. K., Glahn, R. P., Wu, X., Liu, R. H. and Miller, D.D. 2002. Iron bioavailability and antioxidant activity of raisins. J Food Sci (accepted)
  • Wolfe, K. and Liu, R. H. 2003. Apple peels as a value-added food ingredient. J. Agric. Food Chem. 51 (7).
  • Wolfe, K., Wu, X. and Liu, R. H. 2003. Antioxidant activity of apple peels. J. Agric. Food Chem. 51 (3): 609-614.
  • Sun, J., Chu, Y-F., Wu, X., and Liu, R.H. 2002. Antioxidant and antiproliferative activities of fruits. J. Agric. Food Chem. 50 (25): 7449-7454.
  • Boato, F., Wortley, G. M., Liu, R. H., and Glahn, R. P. 2002. Red grape juice inhibits iron availability: application of an in vitro digestion/caco-2 cell model. J. Agric. Food Chem. 50 (23): 6935-6938.
  • Chu, Y-F., Sun, J., Wu, X., and Liu, R. H. 2002. Antioxidant and antiproliferative activities of vegetables. J. Agric. Food Chem. 50 (23): 6910-6916.
  • Gunes, G., Liu, R. H., and Watkins, C. B. 2002. Controlled atmosphere effects on postharvest quality and antioxidant activity of cranberry fruits. J. Agric. Food Chem. 50 (21): 5932-5938.
  • Adom, K. K. and Liu, R. H. 2002. Antioxidant activity of grains. J. Agric. Food Chem. 50 (21): 6182-6187.
  • Liu, R.H. Health benefits of phytochemicals in functional foods (Invited article). 2002. Food Technology Briefing: Innovative Food Ingredients, pp.2-5, October 2002.
  • Dewanto, V., Wu, X., and Liu, R. H. 2002. Processed sweet corn has higher antioxidant activity. J. Agric. Food Chem. 50 (17): 4959-4964.
  • Dewanto, V., Wu, X., Adom, K. K., and Liu, R. H. 2002. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. J. Agric. Food Chem. 50 (10): 3010-3014.
  • Liu, R. H. 2002. Supplement quick fix fails to deliver (Invited article). Food Technology International 1: 71-72.
  • Liu, M, Li, X. Q., Weber, C., Lee, C. Y., Brown, J., and Liu, R. H. 2002. Antioxidant and antiproliferative activities of raspberries. J. Agric. Food Chem. 50 (10): 2926-2930.
  • Abstract Dewanto, V., Wu, X., Adom, K. K., and Liu, R. H. 2002. Effect of thermal processing on the nutritional value of tomatoes. Institute of Food Technologists, IFT Annual Meeting, Anaheim, California, June 15-19, 2002.
  • Yeung , C.K., Glahn, R.P., Wu, X., Liu, R.H. and Miller, D.D. 2002. Iron bioavailability and antioxidant activity of raisins. Institute of Food Technologists, IFT Annual Meeting, Anaheim, California, June 15-19, 2002.
  • Liu, R.H. 2002. Health benefits of phytochemicals in functional foods. Nutraceutical and Functional Foods Division Symposium: Natural Health Products and Dietary Supplements. Institute of Food Technologists, IFT Annual Meeting, Anaheim, California, June 15-19, 2002.


Progress 01/01/01 to 12/31/01

Outputs
Our laboratory reported that phytochemical extracts from apples, grapes, and raspberries have strong antioxidant and anticancer activities, and that the major part of total antioxidant activity is from the combination of phytochemicals. Our found that the combination of phytochemicals in apples is critical to its potent antioxidant activity and antiproliferative activity. Apple with skin displayed higher antioxidant and antiproliferative activities than apple without skin. The total phenolic and flavonoid content was positively related to antioxidant activity and inhibition of cell proliferation. Additionally, the minimal contribution of vitamin C to the antioxidant activity of apples further supports the proposal the other phytochemicals, such as phenolic acids and flavonoids, significantly contribute to the in vitro antioxidant activity of apples. We also found that the phytochemicals in raspberries may have a significant affect on antioxidant and anticancer activity. Raspberries higher in phenolic and flavonoid compounds have higher antioxidant activity. The darker colored raspberry varieties showed greater antioxidant activity than the lighter colored variety. The antioxidant activity of the raspberry was directly related to the total amount of phenolics and flavonoids found in the raspberry, but there was no relationship between antiproliferative activity and the total amount of phenolics/flavonoids found in the same raspberry. The inhibition of cancer cell proliferation is attributed to some unknown compound(s) present in raspberry fruits. We have also examined the synergistic effects of phytochemicals in common fruits. Our results demonstrated the combination of phytochemicals exhibited potent antioxidant activity and synergy. The benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in fruits and vegetables. This explains why no single antioxidant can replace the combination of natural phytochemicals in fruits and vegetables to achieve the health benefits.

Impacts
Those data provide direct supportive evidence for the Five-a-Day program and suggest that consumers obtain their antioxidants from fruits and vegetables for health improvement and disease prevention. This research has a critical economic impact on NY State and US fruits growers and fruits industry, as the New York Apple Association and US apple Association plan concentrate much of their future marketing strategy around these findings.

Publications

  • Liu, M, Li, X. Q., Weber, C., Lee, C.Y., Brown, J., and Liu, R.H. Antioxidant and Antiproliferative Activities of Four Raspberry Varieties. J. Agric. Food Chem. 2002(in press).
  • Liu, R.H. Health benefits of phytochemicals (Invited article). Food Technology International 2002 (in press).
  • Eberhardt, M.V., Lee, C.Y., and Liu, R.H. Antioxidant and anticancer activities of various apple cultivars. 221st ACS National Meeting, San Diego, April 1-5, 2001.
  • Liu, R. H. Health Benefits of Phytochemicals. 4th International Symposium on Nutraceuticals and Functional Ingredients: Scientific and Global Perspectives, Geneva, Switzerland, April 24-26, 2001.
  • Liu, R. H. and Lee, C. Y. An apple a day may keep cancer at bay. Agricultural Research and Education Serving the Nation in Food and Health: A University Exhibition and Reception on Capitol Hill, Capitol Hill, Washington, DC, March 6, 2001.
  • Liu, R. H. Health benefits of apples are attributed to the synergistic combination of phytochemicals". The First International Conference on Food Synergy, Washington, DC, May 10-11, 2001.
  • Liu, R. H., Eberhardt, M. V., Lee, C.Y. Antioxidant and Antiproliferative Activities of Grapes. Institute of Food Technologists, IFT Annual Meeting, New Orleans, Louisiana, 2001.
  • Liu, R. H. Potential synergy in health outcomes from combining processed fruits. Nutrition Division Symposium: How Processing can Optimize the Phytonutrient Benefits of fruits and vegetables. Institute of Food Technologists, IFT Annual Meeting, New Orleans, Louisiana, 2001.
  • Liu, R. H., Eberhardt, M. V., Lee, C. Y. Antioxidant and Antiproliferative Activities of Selected New York Apple Cultivars. New York Fruit Quarterly 9(2):15-17, 2001.
  • Weber, C., Liu M, Li, X. Q., and Liu, R.H. Antioxidant Capacity and Anticancer Properties of Red Raspberry. New York Fruit Quarterly 9(3):25-27, 2001.


Progress 01/01/00 to 12/31/00

Outputs
We found that a combination of substances in the fruit may be more effective at providing these health benefits than a single nutrient. The phytochemicals in fruits produce some powerful antioxidant activity and anti-cancer activity. In laboratory tests, it was determined that a combination of phytochemicals in apples such as flavonoids and polyphenols-provide significant anti-oxidant benefits beyond what single antioxidants such as vitamin C can provide. The total antioxidant activity of phytochemicals in 1 gram of apples with skin is equal to 83.3 mmol Vitamin C equivalents. Apple extracts also contains bio-active compounds that inhibit tumor cell growth in vitro. Phytochemicals in 50 mg apple with skin per ml (on a wet basis) inhibit tumor cell proliferation by 42%. Phytochemicals in 50 mg apple without skin per ml inhibit tumor cell proliferation by 23 %. The apple extracts with the skins significantly reduced the tumor cell proliferation when compared to the apple extracts without skin. These data show that consumption of whole fruits and vegetables may provide sufficient amounts of antioxidants needed to quench reactive oxygen species.

Impacts
From a scientific and human health standpoint, this research provides evidence that consumption of fruits and vegetables may play a significant role in reducing the risk of chronic diseases such as cancer. The findings also suggest that in order to improve their nutrition and health, consumers should be getting anti-oxidants from their diet rich in fruits and vegetables. This research has a critical economic impact on NY State and US apple growers and apple industry, as the New York Apple Association and US apple Association plan concentrate much of their future marketing strategy around these findings.

Publications

  • Liu, R.H. and Espinosa, A. Bio-active Compounds from Fruits and Vegetables in the Prevention of Cancer. In: Agriculture of the New Century: Managing Bio-Resources and Bio-Diversity, National Taiwan University, Taipei, Taiwan, pp.53-59, 2000.
  • Eberhardt, M.V., Lee, C.Y., and Liu, R.H. Antioxidant activity of fresh apples. Nature 405: 903-904, 2000.