In vitro Antidiabetic Activity of Polar and Nonpolar Solvent Extracts from Leucas aspera (Willd.) Link Leaves

BACKGROUND: Diabetes mellitus is a chronic illness, and the management of diabetes is a global problem. Successful treatment is required to prevent complications and organ damages. Herbal medicines are having minimal adverse effects when compared to the available synthetic drugs to treat such chronic diseases and disorders. OBJECTIVE: The present study was aimed to evaluate the antidiabetic and antioxidant activity of polar and nonpolar solvent extracts of Leucas aspera (Willd.) link leaves under in vitro models. MATERIALS AND METHODS: The in vitro antidiabetic activity of petroleum ether (nonpolar) and ethanol (polar) extracts were evaluated in C2C12 cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (cell viability method) and glucose uptake assay. 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method used for the evaluation of in vitro antioxidant activity. RESULTS: Both the polar and nonpolar solvent extracts of L. aspera had shown better antioxidant activity compared to standard (IC(50) = 18.96 and 19.90 μg/mL, respectively). Petroleum ether extract exhibited better cytotoxic activity in C2C12 cell line compared to ethanol extract (concentration of test drug needed to inhibit cell growth by 50% 110.75 ± 5.5 vs. 415.25 ± 8.0 μg/mL) whereas ethanol extract showed enhanced glucose uptake activity than petroleum ether extract in C2C12 cell line at same concentrations. CONCLUSION: From our study results, we concluded that L. aspera (Willd.) link leaves had shown better antidiabetic activity and antioxidant activity under in vitro models. Nonpolar solvent extract produced slightly better activity than polar solvent extract. This study warrants further research and experiments on animal models. SUMMARY: Petroleum ether extract of Leucas aspera (PELA) exhibited slightly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity compared to ethanol extract of L. aspera (EELA). PELA exhibited better cytotoxic activity in C2C12 cell line compared to EELA. EELA had shown enhanced glucose uptake activity than PELA in C2C12 cell line at same concentrations. L. aspera leaf extracts have potential scavenging of DPPH radicals similar to that of ascorbic acid. Overall, PELA (nonpolar) produced slightly better antidiabetic activity and antioxidant activity than EELA (polar). [Image: see text] Abbreviations Used: DM: Diabetes mellitus, EELA: Ethanol extract of Leucas aspera, L. aspera: Leucas aspera, PELA: Petroleum ether extract of Leucas aspera.