Effect Of Saponins From Tribulus Terrestrisl.on Metabolic Syndrome And Analysis Of Its Functional Components

The fruit of Tribulus terrestris L. has been embodied by the Pharmacopoeia of China as a traditional Chinese herb while the pharmacal use of its whole plant is still unclear. Saponins from Tribulus terrestris L. (STT) were the functional components of Tribulus terrestrisL.. RP-HPLC method, with C18 ODS column and refractive index detector, was first established for the rapid and precise analysis of STT. Based on this method, STT was analyzed and the result shows that there are hecogenin and tigogenin but no diosgenin in STT.In order to collect more phytochemical information of Tribulus terrestris L. for the further study coinciding with the National Traditional Chinese Herb Development Program, the saponins from fruit or whole plant, and from samples collected in different time and place were compared. It' s found that there is more tigogenin in whole plant than in fruit and suggests that tigonin maybe the special functional component of Tribulus terrestris L. whole plant. The content of hecogenin and tigogenin varies with time but there is no difference between the samples from Hebei Province and from Shandong Province.Based on our former research, the effect of STT on metabolic syndrome (MS) was studied in this thesis. Diet-induced obese rats, the model of MS in vivo, were made by fed with high fat diet for 18 weeks as the former report has described. Rats were divided into 4 groups as negative control, positive control, STT group and rosiglitazone maleate (RTZ) group. Rats of STT group were administered orally with STT at dose of 40mg/kg.d-1 for 6 weeks. The result shows that STT causes significant reduction in food intake (to 74% of the positive Control). Bodyweight was also significantlyreduced (to 86% of the positive control), increasing only 8 g during the 6 weeks, far less than other groups. The epididymal fat pad weight of STT group also reduced 30% (compared with positive control) and 31% (compared with RTZ group).The oral glucose tolerance test suggests that STT has similar effect to RTZ on improving impaired glucose tolerance. But both of them have no significant difference to positive control in high fat diet condition. STT also increased the insulin sensitivity index and reduced serum glucose, serum insulin but not serum fructosamine.Compared with positive control, serum triglyceride, serum total cholesterol and serum free fatty acid were reduced respectively 44.1%, 22.6% and 26.8% by STT, indicating that STT can improve hyperlipaemia.The suppression of food intake suggests the further study on the potential side-effect of STT. Fed with normal diet, 8 healthy male rats were administered orally with STT at dose of 40mg/kg.d-1 for 6 weeks. The result shows no difference between STT group and control group on food intake on the whole, indicating that STT may do not suppress food intake of healthy rats in normal diet condition. But interestingly, half of the rats in STT group lost bodyweight while others increased more than 10% during the 6 weeks. This fact suggests the individual difference in the sensitivity to STT.To study the pharmacological mechanism of STT at molecule level, based on the experimental results in vivo, the effect of STT on the gene expression of peroxisome proliferative activated receptor α (PPARα) and low density lipoprotein receptor (LDLR) were studied by semi-quantitative RT-PCR.Hepatic cell line L02 was cultured in vitro and its growth activity was measured by MTT method. Between the doses of 50-100ug/ml, STT promoted the growth of L02 cell, but suppressed its growth in other doses. The result indicates that STT has little cytotoxic effect on hepatic cell and promote its growth depend on the dose.Then L02 cell was cultured with different dose of STT for 24 hours. Total RNA was extracted from cells and transcribe reversely to cDNA. Special primers were designed by software for PCR process. Finally,PCR productions were concentrated by gel electrophoresis and analyzed by quantitative image analysis software. The result shows that STT has no effect on the expression of LDLR gene but p...