2株桑树内生菌发酵产物的降血糖作用

通过体外α-葡萄糖苷酶抑制试验和糖尿病模型小鼠动物试验,检验桑树内生菌菌株Stenotrophomonas maltophilia Y1和Micrococcus luteus Y2发酵产物的降血糖作用。结果表明,Y1和Y2菌株发酵液提取物对α-葡萄糖苷酶均具有显著的体外抑制作用,并呈现一定的剂量依赖性,半数抑制浓度(IC50)分别为2 307.56 mg/L和111.58 mg/L,在试验最大剂量下的抑制率分别达到59.17%和69.21%,均高于对照药物拜糖平(抑制率为53.06%)。动物试验表明,饲喂Y1菌株发酵液浓缩产物的糖尿病模型小鼠的空腹血糖(FBG)值和餐后血糖(PBG)值均低于模型组,分别存在显著和极显著差异,而对正常小鼠的血糖无明显影响,也未表现出毒副作用;调查饲喂发酵产物后糖尿病模型小鼠的体质量、进食量、饮水量、排尿量等指标,均得到明显改善。试验结果显示,2株桑树内生菌菌株的发酵液提取物均表现出与1-脱氧野尻霉素(DNJ)相同的体外抑制α-葡萄糖苷酶活性的作用,Y1菌株发酵产物表现出与DNJ相同的降低糖尿病模型小鼠血糖及改善糖尿病症状的作用特点。

Hypoglycemic Effect of Fermentation Broth from Two Strains of Mulberry Endophyte

In this report,we investigated the hypoglycemic effect of fermentation broths from two mulberry endophyte strains namely Stenotrophomonas maltophilia Y1 and Micrococcus luteus Y2 through in vitro inhibition test to α-glucosidase and animal experiment with model mice of diabetes mellitus.The results indicated that extracts of fermentation broths from both Y1 and Y2 strains had significant in vitro inhibitory effect on α-glucosidase which exhibited a dose-dependent pattern to certain extent.Their inhibitory concentration 50%(IC50) was 2 307.56 mg/L and 111.58 mg/L,respectively.At their maximum doses,the inhibition rates reached 59.17% and 69.21% respectively,both higher than the control drug acarbose(the inhibition rates was 53.06%).Animal experiments indicated that both the fasting blood glucose(FBG) and postprandial blood glucose(PBG) of diabetic model mice fed with concentrated broth product of strain Y1 were lower than the model group,and had significant and extremely significant difference respec-tively.Nevertheless,there was no obvious effect on blood glucose of the normal mice,and no toxic and side-effects were observed.It was confirmed that,after administration of fermentation broth products,the body weight,food and water intake,urinary output and other physiological indices of diabetic model mice were improved obviously.The experimental results indicated that fermentation broth extracts of both mulberry endophyte strains have the same in vitro inhibitory effect on α-glucosidase activity with 1-deoxynojirimycin(DNJ),and fermentation broth product of strain Y1 had the same functioning characteristics with DNJ in reducing blood glucose and improving diabetic symptoms of diabetic model mice.