Classification and discrimination of soybean (Glycine max (L.) Merr.) genotypes based on their isoflavone content

Abstract

Isoflavones are phytoestrogens with various types of biological activity. Soybean (Glycine max (L.) Merr.) is the most abundant source of isoflavones in human nutrition. The present study aims to classify the different soybean genotypes according to their isoflavone contents. HPLC analysis of isoflavone content in 22 soybean genotypes was performed. The average content of individual isoflavones in the genotypes analyzed ranged from 2.8 μg/g to 1069,9 μg/g while the most abundant component among the 22 genotypes was malonyl-genistin. The majority of isoflavones had a significantly higher concentration (p < 0.05) in the hybrid genotypes compared to parental genotypes implying heterosis. The principal component analysis (PCA) on isoflavone content and composition, including results in 83 genotypes, was conducted. The contents of daidzein and genistein were positively correlated, which could be explained by their biosynthetic pathways. Using the PCA, analyzed genotypes divided into six coherent groups regarding their specific isoflavone content. Malonyl-genistin and malonyl-daidzin were the most abundant components. Moreover, the significance of the cultivation year on the isoflavone content in soybean was pointed out. The overall results suggested the possibility of selection of suitable soybean extracts according to the content of malonyl-genistin.