The Stability Of Flavonoids From Smilax Glabra Roxb And Its Effects On Lipid Metabolism In Mice

Rhizoma Smilacis Glabrae, also called tufuling in Chinese, is the rhizome of theSmilax Glabra Roxb. RSG has shown many notable bioactivities, such as antioxidative,hypolipidemic, lipid metabolic regulation etc. Studies showed that flavonoids are the mainbioactive constituents of RSG. In the present study, the aqueous stability of astilbin-thedominating flavonoid found in RSG is investigated. Furthermore, the regulation effects offlavonoids from RSG on lipid metabolism in mice are investigated. The main results are asfollow:1. The aqueous stability of astilbin-the dominating flavonoid found in RSGThe influence of temperature, pH value, and solvent on the degradation behavior ofastilbin was studied by HPLC. Results showed that the degradation and isomerization ofastilbin was pH and temperature dependent, and the faster degradation and isomerizationrate with the rise of pH and temperature.The degradation process followed the first-orderkinetics model, and the degradation rate k values increased, whereas half-life (t1/2) valuesdeclined with the rise of pH and temperature. The stability of astilbin was related to itsB-ring substitution, the more substitution the more volatile. The stability of astilbindiffered depending on the solvent and followed the order50%ethanol>ethanol>methanol>50%methanol> water. In different cultural media, the stabilityfollowed the order RPMI1640> high-glucose DMEM>low-glucose DMEM.2. Lipid metabolism regulation effects of RSG flavonoidsCompared with the control group, certain dose of RSG flavonoids could significantlydecrease the body weight, weight gain, fat weight and aliphatic index. Furthermor, thelevels of total TG in serum and TC in liver were also significantly decreased by RSGflavonoids. The level of TC in serum has a decrease trend. However, the TG level in liver,TC and TG level in faeces were unaffected. The results suggested that RSG flavonoids hascertain lipids metabolism regulation effect.3. Study on the lipid metabolism regulation mechanism of RSG flavonoids(1) RSG flavonoids significantly increased the activity of CACT and FAβO, but haveno effects on the activity of FAS,ACAT,HMG-COAR. It suggested that RSG flavonoidscould accelerate hepatic lipolysis of fatty acids and reduce the accumulation of body fat,but have no significant effects on the synthesis of fatty acids and cholesterol.(2) RSG flavonoids significantly increased the activity of SOD and GSH-Px in liverand decreased the content of lipid peroxide MDA. It suggested that RSG flavonoids hadantioxidant activity in in vivo.(3) RSG flavonoids have no significant effects on the activity of AKP, ALT and AST in serum, but showed a decrease trend. It suggested that RSG flavonoids have no liverdamage.