Production Of Genistein From Sophoricoside By Microbial Transformation

Sophoricoside has activities of anti-inflammatory,anti-fertility and prevention of osteoporosis,and is the main component in Chinese medicine Sophorae Fructus and Huaijiao Wan.In recent years,some studies have shown that sophoricoside exerts pharmacological effects only after it is metabolized to its aglycone-genistein,and genistein is better than sophoricoside as to the bioactivities of antioxidant,hypolipidemic,antitumor and prevention and treatment of osteoporosis.So,genistein has better and broader biological activity than sophoricoside.At present,the main production method of genistein is by extraction from natural materials,such as the bean of Sophora japonica,soybean and so on.Because of the low content of genistein in these natural materials,the extraction yield is usually very low,and it impossible to produce genistein by extraction method.Actually,the content of sophoricoside in some natural materials is higher than that of genistein.So,developing a process for production of genistein from sophoricoside has some potential applications in the pharmaceutical industry.Microorganisms have a complicated enzyme system,and possess powerful capacity on decomposition and transformation.If the biotransformation by microbial enzyme was applied on production of genistein from sophoricoside,the process has the advantages of a mild reaction,high specificity,and environment-friendly and so on.In the paper,microbial biotransformation of sophorboside for production of genistein was studied.The research contents and results are as follows:Firstly,10 strains of fungi were isolated and purified from the cultural enrichments culture of Sophora japonica powder.The crude enzymes obtained from these strains were used as catalyst for biotransformation of sophoricoside.Enzyme from a strain,designated as LJH3,could convert sophoricin into genistein with a high yield.Based on morphological characteristics,18 S rDNA nucleic acid sequence and phylogenetic analysis,strain LJH3 was identified as a species of Rhizopus oryzae.Secondly,the medium for strain LJH3 producing ?-glucosidase were optimized by single factor experiment and Response Surface Analysis,and the biotransformation conditions were studied to improve the conversion yield.As a results,the optimum fermentation medium for ?-glucosidase production was composed of 20 g/L yeast extracts powder,7.1 g/L peptone,10.8 g/L maltose,1 g/L MgSO4,1 g/L NaCl and 5 g/L NaCl,with the initial pH at 7.0.The ideal fermentation time was 6 d.The optimum conversion conditions were as follows: concentration of the substrate was 1 g/L,the temperature was 38?,the crude enzyme was diluted 1 times,and the conversion time was 24 h.At these conditions,the conversion yield of genistein reached 80.2%.Finally,a comparative study on antitumor and antioxidant activities of genistein and sophoricoside was performed.The antitumor activities of genistein and sophoricoside were evaluated by MTT on Chinese hamster ovary cells(CHO),pheochromocytoma cells(PC12),human breast carcinoma MCF-7 cells(MCF-7),and their anti-oxidant activities were evaluated by the DPPH free radical scavenging activity assay and hydroxyl scavenging activity assay.As results,the inhibitory rate on CHO,PC12 and MCF-7 cells was 6.61,1.53 and 3.04 times higher than that of sophoricoside respectively when their concentrations were 100 ? g/m L.The scavenging rate of hydroxyl and DPPH free radical of genistein was 6.15 and 5.51 times higher than that of sophoricoside when their concentrations were 1 mg/m L.The results demonstrated that antitumor and antioxidant activities of genistein were significantly higher than that of sophoricoside,so development of genistein as a drug by conversion from sophoricoside has potential applications.