Study On The Therapeutic Effect Of Water Extract From Mulberry Leaf In Type1Diabetic Mice

Diabetes is a metabolic diseases characterized by high incidence, multiple complications and difficulty in eradication. In this paper, Streptozotocin (STZ)-induced type1diabetic mice were treated by water extract of mulberry leaf. The effect of water extract on diabetic mice was observed and investigated. This research could provide a theoretical basis for the development of hypoglycemic drugs using mulberry leaf. The results obtained in this research include the following aspects:1.Water extract and alcohol extract of mulberry leaf were detected by high performance liquid chromatography(HPLC). The results showed1-deoxynojirimycin (DNJ), an effective ingredient in controlling blood glucose concentration, hardly exists in water extract.2. Diet weight, water intake and blood glucose of mice were observed and recorded over40days. The results showed that blood glucose in type1diabetic mice was significantly decreased. Compared with model group, blood glucose of mice treated by high, middle and low doses of water extract was decreased by9.0mmol·L-1,7.8mmol·L-1and5.4mmol·L-1respectively (P<0.01). Weight loss was also curbed obviously while water intake and diet weight only slightly changed during the treatment process.3. Multiple biochemical indexes were tested in type1diabetic mice treated by water extract of mulberry leaf, including glucose tolerance, lipid index, liver index, renal index and serum insulin levels. The results of glucose tolerance experiment indicated area under the curve of blood glucose (AUC) in the treated group was decreased significantly. Compared with the model group, the AUCs of groups treated by high, middle and low doses were decreased by5.4mmol·h/L,4.3mmol·h/L and3.2mmol·h/L respectively. Also, the content of Low density lipoprotein cholesterol (LDL-C). total cholesterol (TC) and triglyceride (TG) in the blood of type1diabetic mice treated by water extract were decreased significantly. Compared with the model group, the average value were decreased by0.8mmol·L-1,0.7mmol·L-1and0.5mmol·L-1. Furthermore, we found that water extract of mulberry leaf shows certain repair function on liver injury and renal injury caused by diabetic. This conclusion was further proved by the tests of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), beta2microglobulin (β2-MG) and urinary microalbumin (ALB). The average values of these five indexes in treated mice were decreased by46.5U·L-1,48.7U·L-1,72.1U·L-1,7.5U·L-1and5.6U·L-1respectively. Mice serum insulin levels in the treated group were risen obviously and the most obvious change was observed in high doses-treated group. Compared with model group and metformin hydrochloride group, the insulin level in mice treated by water extract was increased by6.35mIU·L-1and4.7mIU·L-1. Thus we hypothesized that water extract of mulberry leaf has certain repair impact on mice islet cell.4. Section of mice islet, liver, renal HE staining and cell apoptosis (TUNEL) were observed and analyzed. From the pathological sections, we found the injury of mice islet cells, liver cells and renal cells caused by diabetes was more or less repaired by water extract of mulberry leaf. And there was no obvious improvement in the metformin hydrochloride group and model group. The apoptosis rates of islet cells, renal cells and liver cells of mice treated by water extract were29.7%,28.2%and23.2%on average, which were significantly lower than68.1%,51.2%,54.2%of model group and62.3%,49.4%,56.3%of metformin hydrochloride group. The results not only validate the observation results of pathological section, but also correspond with biochemical index test. The therapeutic effect of water extract of mulberry leaf on mice islet and its health care effect on renal and liver of mice were further proved.5. Full wavelength scanning and high performance liquid chromatography were used to analyze water extract of mulberry leaf. According to experiment results, we speculated that the hypoglycemic constituents from water extract of mulberry leaf may be a compound containing conjugated double bonds or α,β-unsaturated carbonyl structure.