The hypoglycemic effect of Lagerstroemia indica L.and Lagerstroemia indica L.f.alba(Nichols.)Rehd.in vitro and in vivo

Lagerstroemia indica L.has a high medicinal value,its bark,leaves and flowers can be used as medicine.Its flowers are reddish,purple,or white,thereinto,the white one is called L.indica Linn.f.alba(Nichols.)Rehd.,which is a forma of L.indica.In this paper,the hypoglycemic effects of different extracts from flowers of L.indica(LIF)and L.indica L.f.alba(Nichols.)Rehd.(LIAF)were investigated byα-glucosidase inhibitory method in vitro and alloxan-induced diabetic mice model in vivo,respectively.The results in vitro showed that ethyl acetate extracts(EA)of LIF and LIAF(IC_(50)=4.45 and 4.09µg/mL,resepectively)had the highest inhibitory activity ofα-glucosidase,and followed by n-butyl alcohol extracts(BU)(IC_(50)=17.01 and 14.58µg/mL,respectively),and the last was petroleum ether extracts(PE)(IC_(50)=103.29 and 112.47µg/mL,respectively),the activities of all extracts were higher than that of the positive control(acarbose,IC_(50)=1278.83µg/mL).The results in vivo showed that compared with the model control group,each dose group of LIF could significantly(P<0.05,P<0.01 or P<0.001)decrease fasting blood glucose,total cholesterol(TC)level and malondialdehyde(MDA)content in diabetic mice and increase superoxide dismutase(SOD)level(P<0.05)in serum.Partial dose groups of LIF could significantly(P<0.05)decrease postprandial blood glucose,triglyceride(TG)and increase liver glycogen content.Each dose group of LIAF could significantly(P<0.05,P<0.01 or P<0.001)decrease fasting blood glucose,TC level and increase SOD level in serum.Partial dose groups of LIAF could significantly(P<0.05)decrease TG,MDA level and increase liver glycogen content.These results indicate that LIF and LIAF had effective prevention and treatment effects on the development for diabetes.