Study On Genistein Preparation From Sophoricoside In Sophora Japonica L. By Schizophyllum Commune

Isoflavone is a kind of important substances of bioactivity in Leguminosae, which exists in nature almost exclusively as glycoside and aglycone. It shows that isoflavone aglycones are absorbed faster than their glucosides in human's small intestines. So it has become a trend to search for a way of converting glycoside to aglycone in the world. In this paper,Schizophyllum commune DS1 with highβ-glucosidase activity and Sophora japonica L. rich in isoflavone glycosides are screened and used to produced genistein by biotransformation. By detecting the corresponding components, the feasibility and effectiveness of applying S. commune to transform sophoricoside will be studied.First, the research screens the strains with high capability to transform sophoricoside to genistein in ,which belong to 6 different genuses. The strain with the highest enzyme activity and content of genistein is obtained by using p-nitrophenyl-β-D-glucopyranoside as substrate to detect the enzyme activity, and HPLC to analyzing the content of genistein. The results show that the strain S. commune. DS1 produces highest content of genistein and the value could reach 1233.75 mg/L during 2 days incubation, the ratio of genistein transformation could be 24.68 mg/g. The strain S. commune.DS1 is chosen for the experimental strain.Second, the later research focuses on the optimization of transforming the isoflavones of S. japonica L by using S.commune DS1. By experiment, the optimum fermentation conditions are obtained as follows: content of substrate 5%,pH nature (5.0) , strain age 6 days, inoculation volume 10%, culture 1.5 days. The optimization for fermentation conditions of transforming the isoflavones of S. japonica L by using S.commune DS1 in liquid culture system is studied using Response Surface Methodology (RSM). The obtained optimum conditions were as follows: pH nature, content of substrate 35.4 g/L, inoculation volume 15%, the time of fermentation 1.73 d.Under the optimal condition,the content of genistein is 19.36 mg/g by DS1 transformation.Third, it's a preliminary study of the flavonoids trasformation process by using S.commune DS1. The proposed biotransformation pathway of genistein is maybe that the sophoricoside is first hydrolysed to genistein, and then genistein is degraded to biochanin and the other uncertain material. The S.commune DS1 can carry out the transformation of the isoflavones of S.japonica L. for the preparation of genistein.This paper provides a new way to combine the fungi and the traditional Chinese herbs; therefore, the study has gained its theoretical and practical value on processing the traditional Chinese herbs by microbes.