UBC Theses and Dissertations
Determination of some phytoestrogens in alfalfa sprouts Yada, Sylvia Ann (Duffek)
Alfalfa sprouts were grown under selected conditions in order to determine the effect of growth period, light duration, rinse volume and rinse frequency on the accumulation of phytoestrogens. The phytoestrogens were isolated from a crude methanol extract of alfalfa sprouts using ethyl ether. The residue remaining following ethyl ether evaporation was redissolved in methanol for high-performance liquid chromatography (HPLC). A method for HPLC was developed using an octadecylsilane reversed-phase column, UV detection at 254 nm and a gradient methanol/ water solvent system containing 1.0% acetic acid and 0.1 M ammonium acetate. Baseline resolution of the phytoestrogens daidzein, formonone-tin and coumestrol from the alfalfa sprout extracts was achieved with an elution time of 30 minutes. Total phytoestrogen content ranged from 1 to 22 ppm dry weight alfalfa (or less than 2 ppm fresh weight alfalfa) depending on the growth conditions employed. Alfalfa sprouts grown in the dark (0 h light) for the longer growth period (148 h) had significantly greater (P≤ 0.05) contents of daidzein, formononetin and coumestrol than those sprouts from other chosen treatment combinations. Although the contribution of phytoestrogens to the human diet from alfalfa sprouts would appear to be markedly higher than from other common vegetables, the physiological significance of such an intake has not yet been determined.
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