Browsing by Subject "tannins"
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Item Breeding for Bioactive Compounds in Vigna Unguiculata L. (WALP.)(2013-04-30) Gawde, Archana JairamOne of the many ways to address health, obesity and hunger issues is genetic bio-fortification, a strategy of breeding or transforming staple crops with micronutrients and vitamins. This dissertation details efforts to bio-fortify bioactive compounds (phenols, antioxidants, condensed tannins, flavonoids and anthocyanins) in Vigna unguiculata, a staple legume grain crop. Approaches included screening of genetic variation in polyphenolic compositions to identify potential varieties and phenotypes, evaluating the impact of environment (drought stress) on these compositions and elucidating the underlying genetics of their inheritance. Our screening showed significant diversity among genotypes for phenols (2.05 ?15.48 mg GAE/g), condensed tannin (0.05 -15.29 mg CE/g) and antioxidant activity (4.0 -201.8 ?M TE/g). The highest levels of phenols and antioxidant activity were observed in genotypes with light brown, black and red seed coat color, and those with smooth texture and medium maturity (70-90 days). Red and black phenotypes showed the highest content of flavan-3-ols, flavonols and phenolic acids among all color groups, with values of 169 ?g CE/g, 26.17 ?g QHE/g, 27.14 ?g GAE/g for red and 281 ?g CE/g, 23 ?g QHE/g and 25 GAE/g for black phenotypes. When studying the impact of drought stress, genotypeXtreatment and treatmentXyear interactions for bioactive compounds were significant when tested under irrigated and drought stress conditions. Anthocyanins showed a 14 % decrease under drought stress. The genotypes that were stable to drought stress are favorable for breeding programs in preparation towards climate change. An FTNIR method was established for high-throughput, non-destructive quantification of bioactive compounds. This was used in inheritance studies of bioactive compounds. Phenols, condensed tannins and flavonoids showed heterosis in F1 and exhibit transgressive segregation in F2 populations. The information presented in this manuscript will be useful for nutritional improvement of cowpeas, where potential genotypes and phenotypes with health benefits offered by enhanced contents of bioactive compounds can be improved further upon.Item Evaluation of anticancer potential of sorghums with different genetic characteristics and levels of phenolic compounds(2009-05-15) Guajardo Flores, SaraTo evaluate the anticancer potential of sorghum phenolic compounds, different experiments including in vitro and in vivo tests were performed. A set of 25 sorghum samples was evaluated for phenolic (total phenols, flavonoids, anthocyanins and tannins) content, hydrophilic and lipophilic antioxidant capacity using de Oxygen Radical Absorbance Capacity assay (ORAC), and screened for citotoxic properties in mammary, colon and hepatic mammalian cancer cell lines in vitro. Results indicated that there was a wide variability in the phytochemical profile among the different sorghums. Among the 25 samples, sumac sorghum bran had the highest amount of phenolic compounds, flavonoids, tannins and the highest ORAC values. It exerted the highest percent inhibition (near 100%) in mammary, colon and liver cancer cell lines. Sumac sorghum bran was selected for further investigation. Methanolic extracts from sumac whole grain, bran and tannin removed bran were tested in vitro at different concentrations in hormone dependent MCF-7 mammary cancer cells and non hormone dependent Caco2 and HepG2 colon and liver cancer cells. Results indicated that the methanolic extract from sumac bran inhibited 100% of MCF-7 cancer cells at a concentration of 0.5 mg/ml and that the citotoxic effect could be partially due to the tannin content of the extract. Concentrations of 0.5 and 1.5 mg/ml were selected for an in vivo preventive cancer study with 7,12-dymethylbenz(a)-anthracene (DMBA) induced female rats. Bran at low and high concentrations and the correspondent amount of methanol extracts were included in the diet. It was observed that sumac methanol extract at low concentration promoted tumor appearance and development, whereas sumac bran had a preventive effect, however, there were no significant differences in rats treated and un-treated with sumac. Differences between in vitro and in vivo results could be due to the degree of absorption of tannins during the in vivo experiment. To obtain additional data about the effect of sumac extracts on cancer development, a quinone reductase enzyme bioassay was performed. Methanol and hexane extracts from sumac bran induced phase II enzymes in vitro. Phytochemicals of sumac bran sorghum including phenolic compounds and lipid like compounds appeared to have potential for cancer prevention.Item Genetic and Environmental Influences on the Inheritance of Sorghum with a Black Pericarp(2014-07-30) Pfeiffer, Brian KThe black pericarp trait in grain sorghum [Sorghum bicolor (L.) Moench] is a novel trait with complex inheritance. In addition to its uniform, dark appearance, black sorghum grain contains high levels of favorable phenolic compounds such as 3-deoxyanthocyanidins (3-DOA) and condensed tannins which have applications in the specialty food industry as high-antioxidant food additives, natural food colorants, or natural food preservatives. Previous studies have indicated the trait is not fully penetrant in all environmental conditions. Additionally, black sorghum has acceptable agronomic performance, but is significantly lower yielding than other elite grain sorghum hybrids. Further improvement of black sorghum is dependent on understanding the factors?both genetic and environmental?influencing the expression of this trait. The first of two studies investigated the effect of light shading on grain color and grain composition in black Tx3362. Increased light shading reduced, and in some cases, eliminated the black color resulting in red grain production. In addition, increased shading reduced the concentration of 3-deoxyanthocyanidins, total phenols, tannins, and fiber while increasing fat concentrations. Thus the black pericarp trait and associated high phenolic concentrations are strongly influenced by both intensity and duration of sunlight exposure. In the second study, a generation means analysis was performed to determine the genetic factors affecting the trait. This study concluded grain color and associated grain composition traits were influence by additive, dominance, and epistatic effects. The generation means analysis also determined the black pericarp trait is recessive, controlled by multiple genes, and is moderate to highly heritable. Despite these challenges, there is enough variation in breeding populations between red and black parents for further improvement of the trait. Creation of high yielding hybrids with uniformly dark grain and high levels of phenolic compounds will be possible through standard plant breeding practices.