A Study On Composition And Hypolipidemic Effect Of Total Saponins From Kuding Tea

Ilex kudincha C. J. Tseng is belonged to the Aquifoliaceae family, the leaves of Ilex kudingcha are used as an ethnomedicine in the treatment of symptoms related with diabetes mellitus and obesity throughout the centuries in China. Nowadays it becomes the research topic in the study of functional food medicine for the treatment of cardiovascular-related diseases, diabetes mellitus and obesity. In the present study,the bioactive components of Kuding tea was systematically studied using UPLC-QTOF-MS/MS and the mechanism of their lipid lowering effects was studied by the method of RT-PCR from the perspective molecular biology. The results will provide novel evidence for the development of Kuding tea.The saponin standards were isolated and purified by means of D101 macroporous resins, silica gel and C18 column chromatography. The structures of the6 isolated compounds were elucidated by MS compared with that of corresponding standards reported. Finally, the 6 compounds were identified as kudinoside A,kudinoside D, kudinoside F, ilekudinoside R, ilekudinoside D and ilekudinoside M.The fragmentation patterns of 6 saponin standards were investigated and the composition of TS extract from Kuding tea was analyzed by UPLC-QTOF-MS/MS with full scan mode in both positive and negative modes. As a result, fifty-two saponins were identified or characterized in TS extract from kuding tea. The hypolipidemic effect was evaluated in high-fat diet(HFD) induced hyperlipidemia mice. The male kunming mice were divided into four groups, namly control group,hyperlipidemia mode group and two dose groups including the low and high doses of TS extract from Kuding tea(50 mg/kg and 100 mg/kg). After administered by gavage for 4 weeks, the level of serum TC, LDL-C, HDL-C and AI were determined.Simultaneously, the mice were sacrificed and the liver pathology was observed by the photographs stained with oil red-O staining. The results showed that hepatic steatosis caused by HFD in mice had been improved correspondingly in a dose-dependent manner after treated with TS extract from Kuding tea for 4 weeks.Meanwhile, TS extract significantly up-regulated the gene expression of hepatic scavenger receptors including SR-Al, SR-BI and CD36. Therefore, it is reasonable to assume that the over expression of hepatic scavenger receptors was involved in the hypolipidemic effect of Kuding tea on the high-fat diet-induced hyperlipidemic mice.The TS extract could influence these scavenger receptors, and this could be the potential mechanism of TS extract from Kuding tea in the treatment of lipid disorders.