Hypoglycemic effect of Lagerstroemia speciosa (L.) Pers. on alloxan-induced diabetic mice

Lagerstroemia speciosa (L.) Pers. known as "banaba" is traditionally used as a herbal medicine in the Philippines. Although Lagerstroemia speciosa has been shown to produce hypoglycemic effects in some mice models of diabetes, there are no reports of the effects of this substance in alloxan-induced diabetic mice. Thus, the present study aimed to elucidate the hypoglycemic effects of L. speciosa in ICR strain of mice. Diabetes was induced by the intraperitoneal injection of alloxan. Spray dried L. speciosa powder (1000 mg/kg) or decoction (20 ml/kg) was administered on alloxan-induced diabetic male ICR mice for 28 days by gavage. The effects of L. speciosa on blood and urinary glucose levels and body weight, feed intake and water intake were measured. Spray dried L. speciosa powder and decoction significantly reduced blood (P < 0.01) and urinary glucose (P < 0.05) levels of diabetic mice from day 8 to 28 compared with the diabetic control. These mice also had lower (P < 0.05) body weight compared with the diabetic control from day 15 to day 28. The feed intake of diabetic mice was higher (P < 0.05) compared with non-diabetic control and L. speciosa-treated diabetic mice from day 22 to 28. A comparable fluid intake was evident among non-diabetic mice and L. speciosa-treated diabetic mice from day 8 to 28 which was significantly lower (P < 0.01) compared with the diabetic mice. These results suggest that L. speciosa possesses beneficial antihyperglycemic activity in controlling the elevated glucose level in alloxan-induced diabetic mice.