Doctor of Philosophy (PhD)
School of Nutrition and Food Sciences
Bioactive compounds from different agricultural food products have attracted great interest from food industries and researchers for their health promoting functions such as antioxidant, antiaging, anti-inflammatory and anticancer performance. In this study, hydrophilic and lipophilic fraction of two economical agricultural products sweet sorghum millet and sweet potato, as well as two herbs, butterfly pea and basil were extracted. The profiles and contents of phenolics, fatty acids, tocopherols, carotenoids and phytosterols in these selected agricultural products were determined by chromatography and mass spectrum methods. Additionally, the anti-lipid-oxidation capability of sweet sorghum millet and basil, and anti-cancer potential of butterfly pea seed or petal and sweet potato were evaluated by emulsion models (cholesterol or cholesterol-linoleic acid emulsion) and cancer cell lines (HEp-2 and PC-12), respectively. In the study of sweet sorghum millet, nine major hydrophilic phytochemicals were quantified at levels of 8.9 μg/g for cinnamic acid to 1570.0 μg/g for apigeninidin, and lipophilic phytochemicals including α- and γ-tocopherol, lutein and β-carotene were quantified at levels of 7.7, 145.7, 4.8, and 18.8 μg/g, respectively. The total phenolic content, scavenging DPPH activity and the ability of inhibiting cholesterol oxidation or stabilizing linoleic acid in hydrophilic extracts of the sweet sorghum millets were significantly higher than its lipophilic extracts. In Thai holy/sweet basil leaves or seeds, eight phenolics rosmarinic, caftaric, caffeic, chicoric, p-hydroxybenzoic, p-coumaric, protocatechuic acid and rutin were identified. The total phenolic content of Thai sweet basil leaves (TSBL) was significantly higher than Thai holy basil leaves (THBL), Thai holy (THBS) and sweet basil seed (TSBS). The order of scavenging DPPH free radical x activity and anti-lipid-oxidation ability from high to low was THBL, TSBL, THBS and TSBS. Butterfly pea seeds contained fifteen major phenolics such as sinapic acid, epicatechin and hydroxycinnamic acid derivative with concentrations above 0.5 mg/g FW, while its petals contained a group of ternatins (A1, B2, B3, C2, D2 and D3), flavone glycosides, delphinidin derivatives and ellagic acid. Both seeds and petals had four different phytosterols and - and - tocopherol. Linoleic acid is the highest level of fatty acid in both seeds and petals, while phytanic acid was only found in the petals. The cellular study demonstrated that hydrophilic butterfly pea seed (HBS) exhibited significantly higher capability than its petal (HBP) in inhibiting the proliferation of HEp-2 cells. However, the capability of lipophilic extracts of both seed and petal were much lower than their corresponding hydrophilic extracts. In the sweet potato study, most of the phenolic compounds, fatty acids, and phytostrols significantly increased, and four more phenolic acids were found after fermentation of sweet potato due to the enzymatic action of Lactobacillus acidophilus LA-K compared with raw sweet potato. In the anticancer potential study, the fermented sweet potato extracts exhibited higher efficiency than raw extracts in inhibiting the cancer cell PC-12 proliferation. Also, purified hydrophilic extracts of raw or fermented extracts had greater anticancer potential than their corresponding lipophilic extracts. However, each type of extracts had little influence on the normal monkey kidney cell (CV-1) growth. Based on the dissertation research, the natural agricultural extracts could be used as health promoting ingredients in functional food or potential therapeutic ingredients for cancer treatment.
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Shen, Yixiao, "The Bioactive Compounds in Agricultural Products and Their Roles in Health Promoting Functions" (2015). LSU Doctoral Dissertations. 2791.