Isoflavone Composition, Total Polyphenolic Content, and Antioxidant Activity in Soybeans of Different Origin

Abstract

Twenty soybean cultivars, originating from the United States, Russia, Serbia, and China, were analyzed for their isoflavone composition, total polyphenolic content, and antioxidant activity. Isoflavones were extracted by aqueous methanol (80%) and analyzed by high-performance liquid chromatography=diode array detection. Precision and linearity of the applied method were within the standard limits of validation. The highest and the lowest total isoflavone contents were 4.59 and 1.45 mg=g of dried soybean weight, respectively. A significant difference (P < .05) was found in isoflavone concentration among the different cultivars, but it was observed that origin is not a significant factor that could influence isoflavone content in soybeans. Total polyphenolic content varied between 2.13 and 3.45 mg of gallic acid equivalents=g of dried soybean weight. The free radical scavenging activity of soybean extracts assayed by 2,2-diphenyl-1-picrylhydrazyl in terms of 50% inhibitory concentration (IC 50 ) ranged from 1.40 to 3.35 mg=mL. Negative correlation between total polyphenolic content and IC 50 was observed, but there was no correlation between total isoflavone content and IC 50 . On the basis of this study, soybean cultivars with larger potency for biological activity could be recognized.KEY WORDS: 2,2-diphenyl-1-picrylhydrazyl assay high-performance liquid chromatography analysis soybean phytoestrogens

Polyphenol Content and Antioxidant Properties of Colored Soybean Seeds from Central Europe

“…Average isoflavone content among all analyzed cultivars was 2.97 mg/g, which corresponds to previous results obtained from 20 cultivars of yellow seed for which average total isoflavone content was 3.25 mg/g. 31 The average value of isoflavones obtained is considerably higher than those reported in a study performed in the United States (1.86 mg/g) 32 or in India (1.05 mg/g). 6 Black and green seed varieties showed higher content of total isoflavones (3.16-3.58 mg/g) compared with other colored seeds, although the yellow variety had the highest total isoflavone content.…”

“…31,35 This points out the primary role of isoflavones in plants, being predominantly hormonal substances and exhibiting less potent antioxidant activity compared with some other components.…”

Determination of bioactive compounds in fermented soybean products using GC/MS and further investigation of correlation of their bioactivities

“…The anti-oxidant activity can be caused by the phenolic compounds in soybean products [5,6]. Soybean isoflavones have multiple beneficial health effects, especially on estrogen-deficiency conditions such as menopausal symptoms [7] and exhibit high anti-tyrosinase activity [8].…”

Isoflavone composition in F1 soybean progenies

“…Wang and Murphy (1994) reported that in analyzed conditions the sites have less influence than the harvesting year. In our previous work, we showed that soybean genotype plays a significant role in the content and the composition of isoflavones in soybeans, while the origin of soybeans does not have a major impact on these characteristics (Tepavčević et al, 2010). Inheritance of isoflavone content in soybeans is poorly documented, although some genetic effects that underlie the isoflavone content in soybean seeds have been identified (Liang et al, 2007).…”