• Journal of Life Science
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• v.21 no.11
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• pp.1579-1585
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• 2011

Natural anti-diabetic semipurified ethyl acetate fraction was isolated from the submerged-liquid culture of Agaricus blaze Murill (AB) in a medium containing soybean flakes. Hot-water extract of AB (HEAB) was prepared by extraction at $121^{\circ}C$ for 60 min, followed by filtering through a filter presser filled with diatomate. The ${\beta}$-glucan-free HEAB, which was a supernatant fraction from HEAB by precipitation in an 80% ethanol solution, was fractionated into hexane, chloroform, ethyl acetate, and butanol fractions. The inhibition of the ${\alpha}$-glucosidase activity by fractions was 59.0, 17.0, 61.6, and 37.9%, respectively, suggesting that ethyl acetate fraction was the most active. A subfraction having a strong ${\alpha}$-glucosidase inhibitory activity (80.4%) was isolated from the ethyl acetate fraction. This subfraction contained isoflavones (genistin and daidzin) and their conjugates with sugars as potent inhibiters of ${\alpha}$-glucosidase activity. These results suggest that the ethyl acetate fraction or HEAB containing isoflavones and their sugars conjugates could be useful sources for controlling blood sugar levels in humans.