Enhanced Glucose Uptake Activity of Orthosiphon Thymiflorus (Roth) Sleesen Extracts in L6 Rat Skeletal Muscle Cell Lines: An in Vitro Anti-Diabetic Study

Skeletal muscle insulin resistance is a primary defect in Type 2 Diabetes Mellitus, and plants enhancing peripheral glucose uptake are of significant therapeutic interest. This study aimed to investigate the in vitro anti-diabetic potential of chloroform and ethanolic extracts of Orthosiphon thymiflorus by evaluating glucose uptake in L6 myotubes. Differentiated L6 rat skeletal muscle cells were treated with varying concentrations (25, 50, 100 µg/mL) of chloroform and ethanolic extracts of O. thymiflorus. Glucose uptake activity was measured by estimating the residual glucose concentration in the culture medium using the anthrone reagent method and comparing it to untreated control cells and standard insulin. The ethanolic extract exhibited a marked, concentration-dependent increase in glucose uptake. At 100 µg/mL, the ethanolic extract facilitated 68.89% glucose uptake, compared to 66.42% for the chloroform extract and 88.09% for standard insulin at the sameconcentration, while baseline glucose uptake in untreated cells was 31.22%. These findings demonstrate that the ethanolic extract of O. thymiflorus significantly enhances glucose uptake in L6 skeletal muscle cells, indicating potent peripheral insulin-mimetic or insulin-sensitizing activity. This study provides the first in vitro evidence supporting the traditional use of O. thymiflorus for managing diabetes mellitus.