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。通过初步的活性筛选发现,有三株内生假单胞菌发酵液抑制α-葡糖糖苷酶活性和抗氧化活性较好,并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-葡糖糖苷酶活性和清除ABTS+·自由基最好,IC50分别为1.749mg/mL和1.376mg/mL;菌株2s发酵液EAE清除DPPH·自由基活性最好,IC50为0.048mg/mL,总还原力最强,抗坏血酸当量(ascorbic acid equivalent;AEE)为191.627mg AAE/g dw。本研究为利用植物内生菌发酵生产具有降血糖和有抗氧化功能的保健食品提供理论依据。
The
endophytes separated and purified from mulberry twigs, using morphological
observation, physiological and biochemical characteristics and molecular
biology method to identify the species.And we have examined the activities of
inhibition α-glucosidase andantioxidants of the different extractive phases of fermentation
broth ofthe endophytes. The preliminary activities screening shows that three strains of
endophyte Pseudomonas fermentation broth hasagood inhibiting activityα-glucosidase and antioxidant ,so we carried out the
further study.Two
kinds of solvents with different polarity were used, respectively, EAE, NBAE
and WAE. And the fermentation liquid was extracted, and the three segment of
activity was detected. The EAE(Ethyl Acetate Extract) of strain 4cfermentation
broth has a good α-glucosidase activity and ABTS+· free radical
scavenging capacity. IC50 respectively:1.749 mg/mL, 1.376 mg/mL.The
EAE of strain 2s fermentation broth the strongest on the DPPH free radical
scavenging, the IC50 is 0.048 mg/mL.And the total reducing power was
the bestest, and the ascorbic acid equivalent (AEE) is 191.627 mg AAE/g dw. This
research is so vital to offer a reference for the use of mulberry endophytic
bacteria producefunction food.