Studies On The Hypoglycemic Effect Of Flos Lagerstroemiae Indicae And Flos Lagerstroemiae Indicae F. Alba

This dissertation is composed of three chapters. The first chapter summarized the study progress of biological activity of Lagerstroemia genus. The second chapter discussed the α-glucosidase inhibitory activity Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba in vitro. The third chapter studied the hypoglycemic effects Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba on alloxan-induced diabetes in mice.Chapter Ⅰ Research progress of biological activity of Lagerstroemia genusThis chapter summarized the research progress of biological activity of Lagerstroemia genus. Biological activity investigation demonstrated that Lagerstroemia genus possess wide biological activity, in the antiinflammatory, antibacterial, antitumor, antiviral, antioxidant, hypolipidemic, hypoglycemic, hyperuricemia improving, antitussive, anticoagulant and analgesic and so on.Chapter Ⅱ α-Glucosidase inhibitory activity Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba in vitroBy establishing α-glucosidase inhibitory model in vitro, the α-glucosidase inhibitory activities of different extracts from Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba were screened in vitro. Results showed that FLIPE, FLIAPE, FLIEA, FLIAEA, FLIBU and FLIABU from Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba all had good inhibitory activities. The activities were all higher than that of the positive control acarbose(IC50= 1196.94±74.45 μg·m L-1), and α-glucosidase inhibitory activity of extract was positively correlated with concentrations. Among which FLIEA and FLIAEA(IC50= 3.88±0.18 and 4.62±0.98 μg·m L-1) had the highest inhibitory activity of α-glucosidase, and followed by FLIBU and FLIABU(IC50= 13.74±1.46 and 12.89±1.46 μg·m L-1), and the last FLIPE and FLIAPE(IC50= 117.69±5.66 and 112.47±1.70 μg·m L-1).Chapter Ⅲ The hypoglycemic effect Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba in vivoIn this chapter, the mouse diabetic models were established by injection of alloxan, the levels of blood sugar, MDA(malondialdehyde), SOD(superoxide dismutase), TC(total cholesterol), TG(triglyceride) in serum and hepatic glycogen were determined to evaluate hypoglycemic activity of FLIEA, FLIBU, FLIAEA and FLIABU. Compared with diabetic control group, results showed each dose group of Flos Lagerstroemiae indicae could significantly decrease fasting blood glucose, TC level and MDA content in diabetic mice(P<0.05, P<0.01 and P<0.001, respectively), and could significantly increase SOD level in serum(P<0.05, P<0.01 and P<0.001, respectively), compared with positive control group, above each indicator have no statistical significance(P>0.05), and have the same effect with the positive control. Middle dose group of FLIAEA, high dose group of FLIBU and positive control group could significantly decrease postprandial blood glucose(P<0.05, P<0.01), and have the same effect with the positive control. Each dose group of Flos Lagerstroemiae indicae could decrease TG level without statistical significance(P>0.05). Low dose group of FLIEA and positive control group could significantly increase liver glycogen content(P<0.05). Each dose group of Flos Lagerstroemiae indicae f. alba could significantly(P<0.001) decrease fasting blood glucose, and have the same effect with the positive control, but it could decrease postprandial blood glucose without statistical significance(P>0.05). It could significantly decrease TC level(P<0.05, P<0.01 and P<0.001, respectively) and significantly increase SOD level(P<0.05, P<0.01 and P<0.001, respectively) in serum, and have the better effect than the positive control. Each dose group of Flos Lagerstroemiae indicae f. alba could decrease TG level without statistical significance(P>0.05). High dose group of FLIAEA, middle dose group of FLIABU and positive control group could significantly decrease MDA content in diabetic mice(P<0.05, P<0.01). High and middle dose group of FLIAEA and positive control group could significantly increase liver glycogen content(P<0.05), and have the same effect with the positive control. From the above results we can see: Flos Lagerstroemiae indicae and Flos Lagerstroemiae indicae f. alba showed anti-diabetic effect, the mechanism was probably concerned with inhibiting hepatic glycogen excessive degradation and promoting hepatic glycogen synthesis, strengthening antioxidant defense and rectifying the derangement in lipide metabolism system.