Analysis of the anti-T2DM components in dichloromethane fraction of Schisandra sphenanthera and its mechanism

Background: The type 2 diabetes mellitus (T2DM) pharmacodynamic study of various parts of Schisandra sphenanthera was conducted in the previous stage, and it was found that dichloromethane extracted part (SDP) had a significant hypoglycemic effect. Therefore, the components of SDP were analyzed, and the specific mechanism of its anti-T2DM was explored. Methods: We used a high-fat, high-sugar diet in combination with streptozotocin to induce a T2DM rat model, and the model rats were divided into two groups according to body weight and blood glucose. Triglyceride, oral glucose tolerance test, fasting blood glucose, low density lipoprotein cholesterol, superoxide dismutase, insulin, glycated hemoglobin, total cholesterol, nonesterified free fatty acids, alanine aminotransferase, high-density lipoprotein cholesterol, aspartate aminotransferase, malondialdehyde, and glutathione peroxidase were measured, organ indices were calculated, and pathological sections of pancreas and liver were observed. The 16S rRNA V3-V4 region of intestinal flora was sequenced to explore the effect of SDP on biochemical indicators and intestinal flora. Based on the above indicators, the anti-T2DM mechanism of SDP in Schisandra sphenanthera was analyzed. Results: After six weeks of administration, the biochemical indices of diabetic rats were diminished compared to the control group. And SDP could significantly increase the gut microbial alpha-diversity index, resulting in significant changes in the flora of T2DM rats, with increased richness and diversity, reduced harmful flora, and significantly back-regulated the levels of acetic acid, propionic acid, and butyric acid. Conclusion: SDP can improve the symptoms associated with elevated blood glucose, dyslipidemia, elevated fasting insulin levels, and damaged glucose tolerance in rats. SDP against T2DM may be through the control of intestinal flora to normalize and exert anti-diabetic effect; its main active components may be lignans and terpenoids.