Blood Glucose Lowering Effect of Lagerstroemia speciosa L. Leaves Extract on Type 2 Diabetic Rat Model

Abstract

Lagerstroemia speciosa (Lythraceae), commonly known as banaba, is a plant native to the
tropical regions of Southeast Asia that thrives abundantly in Vietnam and has been historically
utilized in traditional medicine. Despite evidence suggesting that its leaves have anti-diabetic
properties, studies investigating the effects of L. speciosa extracts on animal models of type 2
diabetes remain limited. Herein, the effect of dry extract from L. speciosa leaves (VLDE)
collected in Vietnam on blood glucose in type 2 diabetic rats was evaluated. White rats were
divided into five groups, each comprising 10 rats. Group 1 served as the non-diabetic control,
receiving distilled water, while type 2 diabetes was induced in other groups with a high-fat diet
and low-dose streptozotocin. Group 3 received gliclazide at a dose of 20 mg/kg/day as the
positive control, whereas groups 4 and 5 were administered VLDE at doses of 620 mg/kg/day
and 1240 mg/kg/day, respectively, for a treatment duration of 28 days. Blood glucose levels,
blood insulin levels, and insulin resistance indices were evaluated pre-and post-treatment. VLDE
at both doses demonstrated significant blood glucose-lowering effects, accompanied by a
reduction in the HOMA-IR index and elevation in the HOMA-β, QUICKI, and DI indices, as
well as an increase in the pancreatic mass-to-body weight ratio, comparable to the gliclazidetreated group. Our findings underscore the potential of L. speciosa extract as a medicinal
therapeutic agent for type 2 diabetes management, warranting further pre-clinical and clinical
validation for pharmaceutical development.