Progress 10/01/06 to 09/30/11
Outputs
OUTPUTS: The Objectives of the project were to: 1. Characterization of biomass in terms of handling and phytochemical content 2. Development of "green" phytochemical extraction protocols 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity The thrust of the PI's research arc is to integrate the extraction of high value phytochemical-based co-products into cellulosic biorefinery operations, such that multiple product streams can be produced. If the biobased industry comes to a reality, there will be, as an example, 2000 tons per day of biomass at the gate of a 50 million gallon per year cellulosic biorefinery. Most likely, the biorefinery will not be receiving uniform feedstock, but a variety of regional and seasonal biomass. As an example, summer and fall operation of the biorefinery could be based on perennial and annual herbaceous crops and agricultural residues, while winter and early spring operations could utilize woody feedstock, including woody energy crops and forestry residues. Feedstock, such as switchgrass and sweetgum, contain flavonoids and shikimic acid, respectively that can be extracted prior to the cellulosic deconstruction step. However, it is critical that the co-product extraction step is integrated with subsequent downstream processing, meaning that the co-products need to be extracted with water-based solvent systems. The PI presented key posters at the 31rst and 32nd Symposium on Biotechnology for Fuels and Chemicals in San Francisco and Clearwater, respectively, to show that co-products can be extracted from biomass within the context of a biorefinery. The PI chose this dissemination arena because of its close ties to the National Renewable Energy Laboratories who are key-decision makers in bioenergy research and demonstration. The disseminated work includes: Lau C et al. Characterization of xylose oligomers from birchwood xylan during pretreatment. 32nd Symposium on Biotechnology for Fuels and Chemicals, Clearwater, FL; Martin et al Shikimic acid as a co-product from sweetgum. 31th Symposium on Biotechnology for Fuels and Chemicals, San Francisco, CA; Engelberth A et al. Ginsenoside purification: Hot water extraction vs. ultrasonic assisted extraction. 31th Symposium on Biotechnology for Fuels and Chemicals, San Francisco, CA. Specifically, biomass was characterized in terms of its handling and phytochemical content. Sweetgum bark was extracted with 65 degress C water and yielded 1.7 mg/g of shikimic acid, while sweetgum de-barked wood yielded 0.2 mg/g of shikimic acid. Extraction of switchgrass with 90 degrees C water resulted in rutin yields of 82 mg/kg to 185 mg/kg, and quercitrin yields of 37 mg/kg to 193 mg/kg (Objective 1) "Green" phytochemical extraction protocols were developed. A continuous reactor was build and tested on the extraction of milk thistle silymarins, which are excellent model compounds (Objective2). Rutin and quercitrin extracted from switchgrass were tested with respect to their low density lipoprotein oxidation inhibition properties, demonstrating biological activity properties (Objective 3). PARTICIPANTS: This project enabled the training of the following graduate students: 2008 MSc Sathya Vandhana Ravindranath, University of Arkansas 2008 MSc Nirmal Uppugundla, University of Arkansas 2009 PhD Abby Engelberth, University of Arkansas 2009 MSc Julie Abbott, University of Arkansas The following students are currently in training in the PI's laboratory: Chuan Lau PhD (expected graduation 2012) Kris Bunnell PhD (expected graduation 2013) Angele Dijioleu MSc (expected graduation 2012) The project allowed for the training of the following undergraduate students through completion of their honors thesis: Julie Abbott (2008) Jacob Irwin (2008) Kris Bunnell (2009) LaRae Brown (2011) Angele Dijioleu (2010) Helen Wick (2010) TARGET AUDIENCES: Land Grant University communities, Bioenergy and Agricultural industries, State of Arkansas PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We were able to characterize the extraction of phytochemicals using subcritical water; we chose to work on a well-characterized system, such as silymarin (which is a mixture of silichristin, silybin A, silybin B, silydianin) to facilitate result interpretation. The degradation rate constants ranged from 0.0104 min-1 at 100 degreesC for silichristin to a maximum of 0.0840 min-1 at 160 degrees C for silybin B (SB). Half-lives, calculated from the rate constants, ranged from a low of 6.2 min at 160 degrees C to a high of 58.3 min at 100 degrees C, both for silichristin. The respective activation energies for the compounds ranged from 37.2 kJ/gmole for silidianin to 45.2 kJ/gmole for silichristin. In extracting the silymarin with pure ethanol at 140 degrees C, no degradation was observed. Silymarins will most likely not be extracted within the context of a biorefinery; however, this model system is excellent to verify and test whether critical degradation products can be formed. Our results showed that degradation products can be formed when using water as an extraction solvent. It is important to characterize these degradation products because sometimes they can be toxic. These results are important because subcritical water extraction offers many advantages as a "green" solvent over traditional solvent extraction, but compound degradation may occur as a result of the increased temperatures. In commercially applying subcritical water as an extraction solvent, the extraction conditions must be adjusted, such that product losses are minimized. We tested low temperature, 65 degrees C, water on extraction of shikimic acid from sweetgum bark and heartwood. Shikimic acid yields of 1.7 mg/g and of 0.2 mg/g, respectively, were obtained for sweetgum bark and heartwood. Through the equipment grant, NRI/2006-35503-17238, a centrifugal partition chromatography (CPC) instrument was acquired, which is used for compound separation. We were successful in separating ginsenosides and silymarins which served as a good model compounds. We also worked on the separation of switchgrass-derived flavonoids, rutin and quercitrin. The switchgrass-extracted flavonoids decreased the formation of thiobarbituric reactive substance test (low density lipoprotein oxidation inhibition test) which can be taken as a first line indicator of its anti-oxidant potential. Using CPC, we worked on separating carbohydrate oligomers, which are formed when pretreating biomass before fermentation into biofuels and have probiotic properties.
Publications
- 1. Martin E, Cousins S, Talley S, West C, Clausen E and Carrier DJ. 2011 The effect of pre-soaking coupled to pretreatment on the extraction of hemicellulosic sugars and flavonoids from switchgrass (Panicum virgatum, var. Alamo) leafs and stems. Transactions of ASABE (in press)
- 2. Lau C, Bunnell K, Clausen E, Thoma G, Lay J, Gidden J and Carrier DJ. (2011) Separation and purification of xylose oligomers using centrifugal partition chromatography. Journal of Industrial Microbiology 38:363-370.
- 3. Bunnell K, Wallace S, Clausen E, Penney W and Carrier DJ. (2010). Comparison of silymarin extraction from Silybum marianum using a Soxhlet apparatus, batch Parr and countercurrent pressurized hot water reactors. Transactions of ASABE 53: 1935-1940.
- 4. Abbott J, Medina Bolivar F, Martin E, Engelberth A, Villagarcia H, Clausen E and Carrier DJ. (2010). Purification of resveratrol, arachidin-1 and arachidin-3 from hairy root cultures of peanut (Arachis hypogaea) and determination of their antioxidant activity and cytotoxicity. Biotechnology Progress 26: 1344-1351.
- 5. Martin E, Duke J, Pelkki M, Clausen E and Carrier DJ (2010). Sweetgum (Liquidambar styraciflua L.): Extraction of shikimic acid coupled to dilute acid pretreatment. Applied Biochemistry and Biotechnology 162:1660-1668.
- 6. Engelberth A, Clausen E and Carrier DJ. (2010). Comparison of pressurized hot water and ultrasonic extraction methods for recovery of ginseng saponins from American ginseng (Panax) followed by purification using FCPC with HPLC verification. Separation and Purification Technology 72:1-6.
- 7. Engelberth A, Carrier DJ and Clausen E. (2008). Separation silymarins from milk thistle (Silybum marianum L.) extracted with pressurized hot water using centrifugal partition chromatography. Journal of Liquid Chromatography and Related Technology 31:3001-3011.
- 11. Wallace S, Vaughn K, Stewart B, Nagarajan S, Clausen E, Viswanthan T and Carrier DJ. (2008). Silymarin inhibits scavenger receptor-dependent human monocyte adhesion by blocking oxidation-specific epitopes in oxidized-LDL. Journal of Agricultural Food Chemistry 56:3966-3972.
- 13. Vaughn K, McClain C, Carrier DJ, Wallace S, King J, Nagarajan S and Clausen E. (2007). The effect of Albizia julibrissin water extracts on low density lipoprotein oxidization. Journal of Agricultural Food Chemistry 55: 4704-4709.
- 14. Wallace S, Raible J, Carrier DJ, Vaughn K, Griffis C, Clausen E and Nagarajan S. (2007). Pressurized water rivals ethanol as a Silybum marianum extraction solvent for the initiation of copper and cell mediated low-density lipoprotein oxidation. Canadian Journal of Physiology and Pharmacology 85:894-902.
- 15. Lau S, Carrier DJ, Howard L, Lay J, Liyanage R, Bransby D and Clausen E. (2007). Identification and quantification of glycoside flavonoids in the energy crop Albizia julibrissin. Bioresource Technology 98: 429-435.
- 12. Bruner D, Carrier DJ, Belesky D, Pote D and Ares A. (2008). Yield components and nutritive value of Robinia pseudoacacia and Albizia julibrissin in Arkansas, USA. Agroforestry Systems 72: 51-62
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: OBJECTIVES: This project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and renewable energy-destined crops, and finding leads as to their putative biological activity. Specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of ''green'' phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. APPROACH: The first objective of this research program is to work on the characterization of the biomass destined for renewable energy conversion, such that a standardized feedstock is obtained. A consistent feedstock is essential for the economics of the renewable energy industry because it ensures a process consistency which is vital at the industrial scale. This will be accomplished first by studying physical properties such as moisture content, porosity, particle size, bulk density and particle density of potential renewable energy feedstock, and then by developing strategies to bring about a uniform feedstock. Secondly, phytochemical extraction refers to the mass diffusion of target solutes from an insoluble plant solid to its surroundings. Since target solutes or phytochemicals are of different nature, the choice of the appropriate solvent and extraction technique is critical. The extraction of phytochemicals is usually done using organic solvents. Organic solvents, however, can be costly and must be removed and discarded before the biomass, often leaving residues in the phytochemical extract. To replace the use of organic solvents, several alternative techniques, such as liquid-solid, supercritical fluid, pressurized liquid and subcritical water extraction, are available. The use of water as the extraction medium negates the need for solvents and the subsequent need for downstream processing and discharge of waste solvents. Subcritical water extraction technology enables its seamless insertion into the production of renewable fuels using the biochemical platform. In fact, renewable energy feedstock will be in contact with subcritical water during the crucial pretreatment step which occurs at temperatures ranging from 140-200C; thus, phytochemical extraction can occur prior to pretreatment at temperatures ranging from 80-120C. Lastly, the extracted phytochemicals can be characterized and tested for biological activity using in vitro tests, such as the thiobarbituric acid reactive substance (TBARS) test. The TBARS assay monitors the formation of low density lipoprotein. (This work builds upon research conducted and reported under ARK01891.) PARTICIPANTS: PROJECT CONTACT: Name: Carrier, D. J. Phone: 479-575-4993 Fax: 479-575-2542 Email: carrier@uark.edu TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The over arching objective of this project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and renewable energy-destined crops, and finding leads as to their putative biological activity. The specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of ''green'' phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. Through the equipment grant, NRI/2006-35503-17238, a centrifugal partition chromatography (CPC) instrument was purchased, which is used for compound separation. We were successful in separating ginsenosides which serve as a good model for phytochemical compounds. Our laboratory was also successful in separating resveratrol, arachadin-1 and arachadin-3 from crude peanut hairy root extracts. It is important to note that arachadin-1 and arachadin-3 cannot be purchased and this CPC purification effort resulted in production of sought-after reference compounds. The CPC instrument was also critical in separating oligomers from hemicellulose fractions. This is important because oligomers can decompose into fermentation and enzymatic hydrolysis inhibitors during the conversion of biomass to ethanol (like what is shown on POET's project Liberty web info-commercial). Having g quantities of these oligomers allows our laboratory to hydrolyze them and analyze their degradation compounds; hopefully this work will allow us to devise processing operating parameters that minimize the production of these inhibition compounds. Centrifugal partition chromatography (CPC) proves to be a useful separation and purification tool.
Publications
- Abbott J, Medina Bolivar F, Martin E, Engelberth A, Villagarcia H, Clausen E and Carrier DJ. (2010). Purification of resveratrol, arachidin-1 and arachidin-3 from hairy root cultures of peanut (Arachis hypogaea) and determination of their antioxidant activity and cytotoxicity. Biotechnology Progress 26: 1344-1351.
- Lau C, Bunnell K, Clausen E, Thoma G, Lay J, Gidden J and Carrier DJ.(2011) Separation and purification of xylose oligomers using centrifugal partition chromatography. Journal of Industrial Microbiology 38:363. DOI: 10.1007/s10295-010-0799-1
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: OBJECTIVES: This project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and renewable energy-destined crops, and finding leads as to their putative biological activity. Specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of ''green'' phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. APPROACH: The first objective of this research program is to work on the characterization of the biomass destined for renewable energy conversion, such that a standardized feedstock is obtained. A consistent feedstock is essential for the economics of the renewable energy industry because it ensures a process consistency which is vital at the industrial scale. This will be accomplished first by studying physical properties such as moisture content, porosity, particle size, bulk density and particle density of potential renewable energy feedstock, and then by developing strategies to bring about a uniform feedstock. Secondly, phytochemical extraction refers to the mass diffusion of target solutes from an insoluble plant solid to its surroundings. Since target solutes or phytochemicals are of different nature, the choice of the appropriate solvent and extraction technique is critical. The extraction of phytochemicals is usually done using organic solvents. Organic solvents, however, can be costly and must be removed and discarded before the biomass, often leaving residues in the phytochemical extract. To replace the use of organic solvents, several alternative techniques, such as liquid-solid, supercritical fluid, pressurized liquid and subcritical water extraction, are available. The use of water as the extraction medium negates the need for solvents and the subsequent need for downstream processing and discharge of waste solvents. Subcritical water extraction technology enables its seamless insertion into the production of renewable fuels using the biochemical platform. In fact, renewable energy feedstock will be in contact with subcritical water during the crucial pretreatment step which occurs at temperatures ranging from 140-200C; thus, phytochemical extraction can occur prior to pretreatment at temperatures ranging from 80-120C. Lastly, the extracted phytochemicals can be characterized and tested for biological activity using in vitro tests, such as the thiobarbituric acid reactive substance (TBARS) test. The TBARS assay monitors the formation of low density lipoprotein. (This work builds upon research conducted and reported under ARK01891.) PARTICIPANTS: PROJECT CONTACT: Name: Carrier, D. J. Phone: 479-575-4993 Fax: 479-575-2846 Email: carrier@uark.edu TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The over arching objective of this project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and renewable energy-destined crops, and finding leads as to their putative biological activity. The specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of green phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. We were able to characterize the extraction of phytochemicals using subcritical water; we chose to work on a well-characterized system, such as silymarin (which is a mixture of silichristin, silybin A, silybin B, silydianin). The degradation rate constants ranged from 0.0104 min-1 at 100 degrees C for silichristin to a maximum of 0.0840 min-1 at 160 degrees C for silybin B (SB). Half-lives, calculated from the rate constants, ranged from a low of 6.2 min at 160 degrees C to a high of 58.3 min at 100 degrees C, both for silichristin. The respective activation energies for the compounds ranged from 37.2 kJ/gmole for silidianin to 45.2 kJ/gmole for silichristin. In extracting the silymarin with pure ethanol at 140 degrees C, no degradation was observed. However, when extracting with ethanol/water mixtures at and 140 degrees C, degradation increased exponentially as the concentration of water increased. These results are important because subcritical water extraction offers many advantages as a "green" solvent over traditional solvent extraction, but compound degradation may occur as a result of the increased temperatures. In commercially applying subcritical water as an extraction solvent, the extraction conditions must be adjusted, such that product losses are minimized. Through the equipment grant, NRI/2006-35503-17238, a centrifugal partition chromatography (CPC) instrument was purchased, which is used for compound separation. We were successful in separating ginsenosides, which serve as a good model for phytochemical compounds. Using CPC, we are currently working on separating carbohydrate oligomers, which are formed when pretreating biomass before fermentation into biofuels. Finally, we worked on switchgrass and showed that: 1) this crop contains policosanols and 2) contains flavonoids (rutin and quercitrin). The switchgrass-extracted flavoinoids decreased the formation of TBARS, which can be taken as a first line indicator of its anti-oxidant potential. This research work shows that it may be possible to extract, with water at various temperatures, phytochemicals from bioenergy crops prior to their conversion to biofuels. Although high water temperatures can increase the phytochemical extraction rates, caution must be exerted, however, because its use can also cause the formation of adverse compounds; detailed processing conditions must be designed. Centrifugal partition chromatography (CPC) proves to be a useful separation and purification tool. A crop like swithgrass contains interesting phytochemicals that can be extracted in conjunction with biofuels production.
Publications
- Uppugundla N, Engelberth A, Vandhana Ravindranath S, Lay J, Clausen E, Gidden J and Carrier DJ. (2009). Switchgrass water extracts: Extraction, separation and biological activity of rutin and quercitrin. Journal of Agricultural Food Chemistry 57: 7763-7770.
- Vandhana Ravindranath S, Uppugundla N, Lay J, Clausen E, Wilkins M, Ingraham R, West C, Wu Y and Carrier DJ. (2009). Policosanol, α-tocopherol and moisture content as a function of timing of harvest of switchgrass (Panicum virgatum L.). Journal of Agricultural Food Chemistry 57: 3500-3505.
- Duan L, Wallace S, Carrier DJ, King J and Clausen E. (2009). Thermal degradation of silymarin compounds in subcritical water. Applied Biochemistry and Biotechnology 158 (1):362-373.
- Engelberth A, Clausen E and Carrier DJ.(2009) Comparison of pressurized hot water and ultrasonic extraction methods for recovery of ginseng saponins from American ginseng (Panax) followed by purification using FCPC with HPLC verification. Separation and Purification Technology (in press)
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: NON-TECHNICAL SUMMARY: The impact of diet on degenerative diseases has become of increasing interest to researchers, government, and the public. Scientific reports pertaining to interaction between diet and pathogenesis of degenerative disease, in humans and in animals,are currently available. Postponement, even prevention, of onset of degenerative diseases through consumption of phytochemicals offers enormous potential clinical and cost-effective benefits both to human and animal healthcare budgets. Phytochemicals are often extracted from common food crops, such as rice, wheat, oats, vegetables, fruits or oil seeds, but can also be extracted from feedstock that will used in the upcoming renewable energy industry. As an example, the Southeastern US energy crop Albizia. julibrissin contains saponins, which may be effective in controlling coccidiosis (enteric protozoal parasites) in the poultry industry. The potential for saponins in controlling coccidiosis in the broiler industry alone is 25,000 tons annually,worth an estimated $500 million. OBJECTIVES: This project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and renewable energy-destined crops, and finding leads as to their putative biological activity. Specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of ''green'' phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. APPROACH: The first objective of this research program is to work on the characterization of the biomass destined for renewable energy conversion, such that a standardized feedstock is obtained. This will be accomplished first by studying physical properties such as moisture content, porosity, particle size, bulk density and particle density of potential renewable energy feedstock. The second objective is on phytochemical extraction, which is usually conducted using organic solvents. However, organic solvents are costly and must be discarded in a sustainable manner. To replace the use of organic solvents, supercritical fluid, pressurized liquid and subcritical water extraction are available. The use of water, as the extraction medium, negates the need for solvents and the subsequent downstream processing for sustainable discharge. Also, subcritical water extraction technology enables its seamless insertion into the production of renewable fuels using the biochemical platform. In fact, renewable energy feedstock will be in contact with subcritical water during the crucial pretreatment step which occurs at temperatures ranging from 140-200C; thus, phytochemical extraction can occur prior to pretreatment at temperatures ranging from 80-120C. Lastly, the extracted phytochemicals can be characterized and tested for biological activity using in vitro tests, such as the thiobarbituric acid reactive substance (TBARS) test. The TBARS assay monitors the formation of low density lipoprotein. (This work builds upon research conducted and reported under ARK01891.) 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
The over arching objective of this project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and renewable energy-destined crops, and finding leads as to their putative biological activity. The specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of ''green'' phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. Development of ''green'' phytochemical extraction protocols made progress. We were able to separate the silymarin group into their individual phytochemicals by centrifugal partition chromatography: the development of this technique will be very useful for separating phytochemicals from renewable energy feedstock pretreatment related extraction. In addition to the extraction of phytochemicals from renewable energy feedstock, we reported on the supercritical fluid extraction of lycopene from tomato. Biological activity of silymarins, using the low density lipoprotein (LDL) model, was demonstrated. Finally, the safety of silymarins, which are extracted from the medicinal plant crop milk thistle, was demonstrated. Work is ongoing with respect to the purification of mg to g quantities of phytochemicals extracted by 80-120C water from Panicum virgatum (switchgrass) and from Albizia julibrissin, using centrifugal partition chromatography (CPC). Also, the CPC purification of stilbenoids, which are produced by peanut hairy root cell culture, and their ensuing activity in the TBARS assay is currently pursued.
Publications
- Engelberth A, Carrier DJ and Clausen E. (2008). Separation silymarins from milk thistle (Silybum marianum L.) extracted with pressurized hot water using centrifugal partition chromatography. Journal of liquid chromatography and related technology 31: 3001-3011.
- Wallace S, Vaughn K, Stewart B, Nagarajan S, Clausen E, Viswanthan T and Carrier DJ. (2008). Silymarin inhibits scavenger receptor-dependent human monocyte adhesion by blocking oxidation-specific epitopes in oxidized-LDL. Journal of Agricultural Food Chemistry 56: 3966-3972.
- Gurley B, Swain A, Hubbard M, Williams K, Barone G, Hartsfield F, Tong Y, Carrier DJ, Cheboyina S and Battu S. (2008). Clinical assessment of CYP2D6-mediated herb-drug interactions in humans: Effect of milk thistle, black cohosh, goldenseal, kava kava, St.John's wort and echineacea. Molecular Nutrition and Food Research 52: 755-763.
- Vaughn K, Carrier DJ, Howard L, King J. and Clausen E. (2008). Extraction of lycopene from watermelon using supercritical fluid extraction (SFE). Bioresource Technology 99: 7835-7841.
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Progress 01/01/07 to 12/31/07
Outputs
The over arching objective of this project is aimed at assisting in the development of a knowledge-based process engineering research program devoted to the extraction of phytochemicals from traditional food crops and energy-destined crops, and finding leads as to their putative biological activity. The specific objectives are: 1.Characterization of biomass in terms of handling and phytochemical content; 2. Development of ''green'' phytochemical extraction protocols; and 3. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity. Characterization of biomass in terms of handling and phytochemical content made progress through a non-funded collaboration with the Agricultural Research Service (ARS) Booneville, AR station. We worked on Albizia julibrissin and Robinia pseudoacacia, which are two potential energy crops and have determined that Albizia julibrissin and Robinia pseudoacacia do not contain mimosine and robinin,
respectively. Mimosine and robinin are two potentially toxic phytochemicals and the demonstrated lack of toxicity is important because these crops could be alternatively used as energy and feed crops. Development of ''green'' phytochemical extraction protocols made progress through the following. We demonstrated that the flavonoids quercitrin and hyperoside can be extracted with water from Albizia julibrissin, indicating that this extraction could possibly be articulated with the biorefinery and could add value to the whole transformation operation. Evaluation of the efficacy of the extracted phytochemicals in terms of their biological activity made progress through the following. These water extracted quercitrin and hyperoside do have low density lipoprotein (LDL) oxidation inhibition activities as demonstrated by the thiobarbituric acid reactive substance (TBARS) assay. Work was done to compare the biological activity of solvent and water extracted phytochemicals in our Silybum
marianum model system. Results showed that the water extract was as biologically active as the extract prepared with solvents.
Impacts
Work is ongoing in the purification of mg to g quantities of phytochemicals extracted by subcritical hot water from Panicum virgatum, Albizia julibrissin and Silybum marianum using the recently acquired centrifugal partition chromatography instrument. The activity of the compounds is assessed with the thiobarbituric acid reactive substance (TBARS) assay.
Publications
- Wallace S, Vaughn K, Carrier DJ, Clausen E and King J. 2006. Application of Bioassays for Evaluating Critical Fluid Extracts. Proceedings of ISSF2006, Kyoto Japan
- Lau S, Carrier DJ, Howard L, Lay J, Liyanage R, Bransby D and Clausen E. 2007. Identification and quantification of glycoside flavonoids in the energy crop Albizia julibrissin. Bioresource Technology 98: 429-435.
- Vaughn K, McClain C, Carrier DJ, Wallace S, King J, Nagarajan S and Clausen E. (2007). The effect of Albizia julibrissin water extracts on low density lipoprotein oxidization. Journal of Agricultural Food Chemistry 55: 4704-4709.
- Wallace S, Raible J, Carrier DJ, Vaughn K, Griffis C, Clausen E and Nagarajan S. 2007. Pressurized water rivals ethanol as a Silybum marianum extraction solvent for the initiation of copper and cell mediated low-density lipoprotein oxidation. Canadian Journal of Physiology and Pharmacology 85: 894-902.
- Bruner D, Carrier DJ, Belesky D, Pote D and Ares A. 2008. Yield components and nutritive value of Robinia pseudoacacia and Albizia julibrissin in Arkansas, USA. Agroforestry Systems 72: 51-62.
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