Two dietary polyphenols, delphinidin and resveratrol, were selected for this study; delphinidin, an anthocyanin flavonoid, was found to elicit cardioprotective properties from a pilot study and resveratrol, a stilbene flavonoid, one of the most studied of the polyphenols and was chosen as a worthy comparator. <i>In vitro</i> studies using cultured endothelial cells exposed to a variety of reactive oxygen species (ROS) were used to determine if delphinidin and resveratrol could protect these cells from oxidative damage. It was found that physiological concentrations of delphinidin protected these cells from hydroxyl-radical damage. However, resveratrol failed to show any protective effects. Oxidative stress was induced in porcine coronary artery using diethyldithiocarbamate (DETCA), an inhibitor of the superoxide dismutase (SOD). Sensitivity to nitric oxide (NO) was preserved in endothelium-denuded vessels that were pre-treated with delphinidin, but not with resveratrol. However, studies where a balloon catheter was used to induce injury to the endothelium, delphinidin pre-treatment did not preserve sensitivity to NO in these vessels. Taken together, these results suggest that delphinidin, but not resveratrol, has potential to protect the endothelium from oxidative stress by preserving/protecting NO bioavailability and by acting directly as an antioxidant or indirectly upregulating antioxidant systems.

A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Pharmacy Johannesburg. 2004 / As part of investigation of the biological activities of South African plant, a phytochemical and pharmacological investigation was carried out on five indigenous Vitex species; V. obovata ssp. obovata, V.obovata ssp. wilmsii, V. pooara, V. rehmannii and V. zeyheri . The chemical composition of the essential oils was determined using gas chromatography and mass spectrometry, and 1.8-cineole, a- copaene , caryophyllene oxide and y-muurolene were found to be the most abundant constituents in the essential oils of both V. obovatassp. obovataand V. obovata sssp. wilmsii. / IT2018

The emerging scientific evidences on the role of food components in prevention of several chronic diseases are the momentum for shifting from a traditional focus on production to enhancement of nutritional quality. To further understand the role of these phytochemicals this dissertation describes the development of rapid analytical and isolation methods, and the effect of production systems and processing techniques on the levels of phytochemicals in citrus fruits. In the first study, a simultaneous high performance liquid chromatography (HPLC) method for the rapid analysis of amines and organic acids was developed. The simultaneous extraction and analysis of samples provides an economical method for analyzing a large number of samples. In the second study, rapid separation method of potent health beneficial phytochemicals such as polymethoxyflavones from citrus peels using flash chromatography was developed. Using the developed method, five polymethoxyflavones were separated and isolated with high purity in gram level quantity. In the third study, the levels of phytochemicals in organically and conventionally grown lemons and their storage at market simulated conditions were determined. Results suggest that organically produced citrus fruits have higher content of organic acids and flavonoids than conventionally produced. The fourth and fifth study determined the influence of household processing (blending, juicing, hand squeezing techniques) and emerging processing (high pressure processing [HPP], thermal processing) on the phytochemicals content of ‘Rio Red’ grapefruits. Fruits processed by blending had significantly higher levels of flavonoids, furocoumarins and limonin compared to juicing and hand squeezing, while HPP enabled in extending the shelf life of the processed juice without any adverse effects. Therefore, consuming grapefruit juice processed by blending may provide higher levels of health beneficial phytochemicals. The sixth study describes a rapid flash chromatography method for isolation of PMFs and furocoumarins from citrus industrial by products such as peel oil. In the seventh study the developed method was applied to isolate 10 different phytochemicals from an unexplored citrus species, Miaray mandarin (Citrus miaray TAN.). Among them, the 5,7,8,3',4' pentamethoxyflavone was isolated for the first time from the genus Citrus.

Thesis (M.S.)--The University of North Carolina at Greensboro, 2008. / Directed by Joel Bowen; submitted to the Dept. of Chemistry and Biochemistry. Title from PDF t.p. (viewed Aug. 26, 2009). Includes bibliographical references (p. 88-90).

No description available.

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

There is an increasing need of automation for routine tasks like sorting agricultural produce in large scale post-harvest processing. Among different kinds of sensors used for such automation tasks, near-infrared (NIR) technology provides a rapid and effective solution for quantitative analysis of quality indices in food products. As industries and farms are adopting modern data-driven technologies, there is a need for evaluation of the modelling tools to find the optimal solutions for problem solving. This study aims to understand the process of evaluation of the modelling tools, in view of near-infrared data obtained from green leafy vegetables. The first part of this study deals with prediction of the type of leafy green vegetable from the near-infrared reflectance spectra non-destructively taken from the leaf surface. Supervised classification methods used for the classification task were k-nearest neighbors (KNN), support vector machines (SVM), linear discriminant analysis (LDA) classifier, regularized discriminant analysis (RDA) classifier, naïve Bayes classifier, bagged trees, random forests, and ensemble discriminant subspace classifier. The second part of this study deals with prediction of total glucosinolate and total polyphenol contents in leaves using Partial Least Squares Regression (PLSR) and Principal Component Regression (PCR). Optimal combination of predictors were chosen by using recursive feature elimination. NIR spectra taken from 283 different samples were used for classification task. Accuracy rates of tuned classifiers were compared for a standard test set. The ensemble discriminant subspace classifier was found to yield the highest accuracy rates (89.41%) for the standard test set. Classifiers were also compared in terms of accuracy rates and F1 scores. Learning rates of classifiers were compared with cross-validation accuracy rates for different proportions of dataset. Ensemble subspace discriminants, SVM, LDA and KNN were found to be similar in their cross-validation accuracy rates for different proportions of data. NIR spectra as well as reference values for total polyphenol content and total glucosinolate contents were taken from 40 samples for each analyses. PLSR model for total glucosinolate prediction built with spectra treated with Savitzky-Golay second derivative yielded a RMSECV of 0.67 μmol/g of fresh weight and cross-validation R2 value of 0.63. Similarly, PLSR model built with spectra treated with Savitzky-Golay first derivative yielded a RMSECV of 6.56 Gallic Acid Equivalent (GAE) mg/100g of fresh weight and cross-validation R-squared value of 0.74. Feature selection for total polyphenol prediction suggested that the region of NIR between 1300 - 1600 nm might contain important information about total polyphenol content in the green leaves.

No description available.

Liver is one of the most important organs in the body that maintains the homeostasis of metabolism, immunity, detoxification and hematopoiesis. A large number of acute and chronic intoxications and diseases can influence the normal functions of the liver, leading to irreversible liver damage and even cancer. Currently, applying herbs or herbal derivatives in the prevention and therapy of acute and chronic liver injury receive numerous attentions since they hold great potentials as food supplements in the treatment strategy of liver injuries. There were two major hypotheses of this current work namely: a)In CCl4-inducedacute liver injury animal model, whether pre-treatment with garlic derived S-allylmercaptocysteine (SAMC)or Wolfberry derived Lycium barbarum polysaccharides (LBP)could reduce liver injury, oxidative stress and inflammation partly through a NF-κB-dependent pathway. SAMC or LBP could also promote liver regeneration after acute damage. b)In non-alcoholic steatohepatitis (NASH)-induced chronic liver injury animal model, whether administration of SAMC or LBP along with high-fat diet induction could attenuate liver injury, lipid metabolism dysfunction, fibrosis, oxidative stress, inflammation, apoptosis and transcription factors activities in the liver. In this study, SAMC and LBP were applied in a carbon tetrachloride (CCl4) induced mice acute liver injury model and a high-fat diet induced non-alcoholic steatohepatitis model. In the acute model, an eight-hour CCl4treatment induced severe acute liver injury. Pre-treatment with SAMC or LBP (1) attenuated hepatic histological injury; (2) reduced serum ALT level; (3) ameliorated oxidative stress; (4) reduced expression of inflammatory mediators and chemokines; (5) promoted liver regeneration; and (6) decreased NF-κB activity. Vehicle-treated SAMC or LBP did not exhibit obvious adverse effects on healthy mice. In the chronic NASH model, when compared with control rats, NASH rats showed typical clinical features of human NASH patients, including increased liver injury, lipid content, oxidative stress, inflammation, and apoptosis. In comparison, SAMC or LBP co-treated NASH rats showed (1) reduced fat accumulation, cellular necrosis, collagen formation, as well as reduced serum ALT and free fatty acids levels; (2) restored insulin resistance related kinase phosphorylation status which had been altered during NASH; (3) reduced pro-fibrogenic factors; (4) restored antioxidant enzymes, as well as attenuated end-products of lipid peroxidation and NO production through a cytochrome P450 2E1-dependent pathway; (5) reduced hepatic pro-inflammatory mediators and chemokines production; (6) diminished activities of nuclear transcription factors (NF-κB and AP-1); and (7) ameliorated hepatic cellular apoptosis through a p53-dependentpathwaywhich was under the regulation of LKB1/AMPK axis and PI3K/Akt axis. In conclusion, our data demonstrated that SAMC or LBP consumption protects the liver from acute injury caused by CCl4and chronic damages caused by a high-fat diet. These effects were mainly mediated by the amelioration of hepatic oxidative stress, inflammation, and cell death. In the NASH model, SAMC or LBP also improved hepatic lipid metabolism, fibrosis, and apoptosis. Therefore, the present study proposed that both garlic and Wolfberry, which are novel hepatoprotective herbal products, can be taken as part of the daily dietary supplements in the prevention of acute and chronic liver injury. / published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy