Solvent Effects on Extraction and HPLC Analysis of Soybean Isoflavones and Variations of Isoflavone Compositions As Affected by Crop Season

Abstract

Spring (February to June) and fall (August to December) crops of soybean grown yearly in Taiwan with reverse temperature patterns provide a novel model to assess the effect of the crop season. In this study, three soybean cultivars, namely CH 1, VS-KS 2, and HBS, were grown for 2001 fall, 2002 spring, 2003 fall, 2004 spring, 2004 fall, and 2005 spring crops. The harvested and sun-dried soybeans were lyophilized, pulverized, and stored at -25 degrees C until HPLC analyses of isoflavone compositions were performed. As affected by extraction solvent and HPLC mobile phase, the amount of isoflavones extracted by methanol-H(2)O was higher than those extracted by acetic acid-acetonitrile. In addition, when both extracts were subjected to HPLC analysis with reversed C18 column run respectively with methanol-H(2)O and acetic acid-acetonitrile mobile phases, malonyldaidzin, malonylglycitin, and malonylgenistin were not detected in the former phase. Accordingly, all harvested soybeans were subjected to methanol-H(2)O extraction and HPLC analysis with the acetic acid-acetonitrile mobile phase. Among the detected soybeans, daidzin, genistin, malonyldaidzin, and malonylgenistin were the majors and glycitin, malonylglycitin, daidzein, and genistein were the minors of isoflavones. As affected by crop season for each cultivar grown for 3 years, daidzin, genistin, malonyldaidzin, and malonylgenistin contents of soybeans of the fall crops were significantly higher than those of their spring crops ( p < 0.05).

Quantitative Determination of Isoflavones in Soy Based Nutritional Supplements by High-Performance Liquid Chromatography

“…These variations are due to several reasons, such as e.g. cultivation and variability in the natural isoflavone content (Tsai et al, 2007). Also the harvestA C H T U N G T R E N N U N G ing date is likely to have an influence on the ratio of aglycone and glucosidically bound forms of isoflavones.…”

Selective extraction of Cyclopia for enhanced in vitro phytoestrogenicity and benchmarking against commercial phytoestrogen extracts

“…The yield and TPP of the DMEs were slightly higher than previously reported [30,40]. Since the plant material was not from the same harvesting (harvest time, year and age of bush differed), this difference could be expected, given the influence of environmental parameters on the phenolic composition of plants [48,50]. Apart from environmental influences, the plantations of each species were established with seedlings, which could further contribute to compositional differences.…”

“…The polar solvents, 50% methanol-distilled water or water, extracted little to no estrogenic activity. Other parameters that could affect the effectiveness of extraction are ratio of solvent to plant material [44], extraction method [46,49], and time and temperature of extraction [44,48]. A study of additional factors that could affect the extraction effectiveness of Cyclopia may be considered in future, especially an investigation of the effects of temperature in light of our results with the "cup-of-tea" extraction.…”

“…For example, extraction of yam with ethyl acetate, but not methanol or n-hexane, produced extracts with estrogenic activity [45] while in other studies methanol or ethanol extracts of ginseng root or soybean, respectively, yielded estrogenic extracts [44,46]. Less polar solvents such as acetonitrile have been suggested by some to be more effective for soybean extraction [47] while other authors present data suggesting that more polar solvents, such as methanol-water, extract more estrogenic compounds from soybean [48]. Our study suggests that less polar solvents extract more estrogenic activity.…”

Comparing extraction methods for the determination of tocopherols and tocotrienols in seeds and germinating seeds of soybean transformed with OsHGGT

“…The quantity of vitamin E in cereals, as well as vegetables, is influenced by the species, variety, maturity and growing conditions (Tsochatzis et al, 2012). Moreover, variations in vitamin E values result from many factors, including sample preparation, processing procedures and the conditions of the analytical methods (Clark and Synder, 1989;Lee et al, 2006;Peres et al, 2006;Tasai et al, 2007).…”