从严格表面消毒的桑枝中分离、纯化内生菌,根据菌株的形态与培养特征、生理生化特性、16S r DNA序列分析对其进行菌种鉴定,并检测其发酵液不同萃取相抑制α-葡萄糖苷酶活性和抗氧化活性.通过初步活性筛选发现,有3株内生假单胞菌发酵液抑制α-葡萄糖苷酶活性和抗氧化活性较好,进一步对其发酵液的乙酸乙酯、正丁醇萃取部分及其剩余水相进行活性检测.结果显示,菌株4c发酵液乙酸乙酯相(ethyl acetate extract,EAE)抑制α-葡萄糖苷酶活性和清除ABTS+·最好,IC50分别为1.749 mg/mL和1.376 mg/mL;菌株2s发酵液EAE清除DPPH.活性最好,IC50为0.048 mg/mL,总还原力最强,抗坏血酸当量(ascorbic acid equivalent,AEE)为191.627 mg AAE/g dw.%The endophytes were separated and purified from mulberry twigs,and their species were further identified using morphological observation,physiological and biochemical characteristics and molecular biology method.The inhibition of α-glucosidase and the activities of antioxidant in different extractive phases of fermentation broth of the endophytes were examined.The preliminary activities screening showed that three strains of endophyte Pseudomonas fermentation broth had a good inhibiting activity for α-glucosidase and good antioxidant activities.Two kinds of solvents with different polarity were used,and named as EAE,NBAE and WAE,respectively.The fermentation liquid was extracted and detected.The EAE (ethyl acetate extract) of strain 4c fermentation broth has a good α-glucosidase inhibition and ABTS + · scavenging capacity.IC50 was 1.749 mg/mL and 1.376 mg/mL respectively.The EAE of strain 2s fermentation broth had the strongest DPPH · scavenging activity with the IC50 of 0.048 mg/mL and the best total reducing power with the ascorbic acid equivalent (AEE) of 191.627 mg AAE/g dw.This research is so vital to offer a reference for the application of mulberry endophytic bacteria in producing function food.
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