The Isoflavonoid Constituents and Biological Active of Astragalus Radix by Fermentation of β-glucosidase Strains

This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/ by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: In this study, the radix of Astragalus membranaceus Bunge extract fermented by Saccharomyces cerevisiae, Weissella cibaria, and Pediococcus pentosaceus to increase the levels of isoflavonoid aglycone contents. Methods and Results: In order to change the in isoflavonoids, we fermented the radix of A. membranaceus extracts with microorganisms that have β-glucosidase activity. Besed on the β-glucosidase activity, we selected three strains, Weissella cibaria, Pediococcus pentosaceus, and Saccharomyces cerevisiae. HPLC analysis revealed that the levels of isoflavonoid aglycones were increased in all fermentation cases, and the extracts fermented by S. cerevisiae showed the highest levels of isoflavonoid aglycones. We evaluated the antioxidant activity, anti-wrinkle effects and whitening effects of the S. cerevisiae-fermented extracts using the DPPH assay, tyrosinase inhibition activity assay, and collagenase inhibition activity assay. We confirmed higher activity in S. cerevisiae-fermented extracts than in control, with the half maximal inhibitory concentration (IC50) value of 565.1 ± 59.1 μg/ml in DPPH radical scavenging activity, tyrosinase inhibition rate of 78.4 ± 0.9%, and collagenase inhibition rate of 83.8 ± 1.1%. Conclusions: We selected three stains of microorganisms showing high β-glucosidase activity, W. cibaria, P. pentosaceus and S. cerevisiae. Isoflavonoid glycones in the radix of A. membranaceus were converted to isoflavonoid aglycones by fermentation. In addition, the fermented radix of A. membranaceus exhibited antioxidant activity, anti-wrinkle effect, whitening effect and radical scavenging activity.