Analysis Of Active Components Of Mulberry Leaves In Cold Region For Lowering Blood Sugar And Evaluation Of Their Effects On Diabetic Mice

Diabetes is one of the main stubborn diseases that plague human health.At present,most Western medicines are used for the treatment of diabetes,but the side effects are relatively large.Mulberry leaves can not only control blood sugar but also have low toxicity and side effects,so they have been recorded on the contents of drug and food homologous items until now.In this study,we selected Morus abla L.cv.Longsang 1 that was cultivated in Heilongjiang as the experimental materials to explore the hypoglycemic effect of cold mulberry leaves and analyze its main active ingredients.In vivo hypoglycemic experiments,high glycaemia mice were used as animal models to evaluate the hypoglycemic activity of the aqueous extract by blood biochemical indicators,intestinal microbiota,and observation of kidney tissue sections.The ?-glucosidase activity and anti-protein glycosylation activity of the active substance of the aqueous extracts were studied in vitro experiments.Single factor,orthogonal experiments were used to separate and extract the active ingredients of mulberry leaves,and their main components were identified by mass spectrometry.Results showed that high-dose of water extracts of the mulberry leaves can reduce the blood glucose of diabetic mice by 28.17% and the glucose tolerance by 19.02%.Furthermore,water extracts of the mulberry leaf can also reduce the content of free fatty acid and tumor necrosis factor ? in serum.The medium dose of water extracts of the mulberry leaves can reduce insulin by 14.67% and glycated serum protein by 9.15%,while low dose can increase insulin sensitivity index by 12.12% and resistance index by 55.17%.At the same time,each dose can improve the blood lipids of diabetic mice,kidney damage and intestinal microbiota caused by diabetes in varying degrees.The results of in vitro experiments showed that alkaloids have obvious inhibitory effect on ?-glucosidase activity,followed by flavonoids,with the inhibition rates of 87.29±1.32% and 86.12±1.79% respectively,which are better than the positive control at the same concentration.While the inhibitory effect of flavonoids on protein glycosylation is most obviously,the inhibition rate is reached 72.61±0.23% compared with other components.The flavonoids that play a major role in reducing blood sugar were further separated and purified.The best extraction conditions were: material-liquid ratio of 1:20,extraction temperature of 60?,extraction time of 1 h,and the best purification material was AB-8 macroporous Resin,the extraction rate reached 0.61%.Mass spectrometry analysis confirmed that the main components of mulberry leaf flavonoids obtained rutin,isoquercitrin,astilin,kaempferol,quercetin,and scopolamine.This study confirmed that the cold mulberry leaves have a certain hypoglycemic effect,which provides a new diet therapy for the treatment of diabetes,and also provides theoretical support for the development of functional components of cold mulberry leaves.