Aims:The present study was undertaken to evaluate the effect of methanolic leaf extract of Gymnema sylvestre (MLGS) on glucose transport (GLUT) and insulin resistance in vitro.Materials and Methods:Peroxisome proliferator-activated receptor-gamma (PPAR-γ) and GLUT-4 expression were assessed in L6 myotubes for concluding the GLUT activity, and adiponectin and leptin expression was studied in 3T3 L1 murine adipocyte cell line to determine the effect of MLGS (250-750 μg/ml) on insulin resistance.Results:The findings of the experiments have demonstrated a significant and dose-dependent increase in glucose uptake in all the tested concentrations of MLGS, further the glucose uptake activity of MLGS (750 μg/ml) was at par with rosiglitazone (50 μg/ml). Concomitantly, MLGS has shown enhanced GLUT-4 and PPAR-γ gene expressions in L6 myotubes. Furthermore, cycloheximide (CHX) had completely abolished the glucose uptake activity of MLGS when co-incubated, which further confirmed that glucose uptake activity of MLGS was linked to enhanced expression of GLUT-4 and PPAR-γ. In addition, in another experimental set, MLGS showed enhanced expression of adiponectin and leptin, thus confirms the ameliorative effect of MLGS on insulin resistance.Conclusion:These findings suggest that MLGS has an enhanced glucose uptake activity in L6 myotubes, and ameliorate the insulin resistance in 3T3 L1 murine adipocyte cell line in vitro.

The present study was undertaken to evaluate the influence of the methanolic fruit extract of Momordica cymbalaria (MFMC) on PPARγ (Peroxisome Proliferator Activated Receptor gamma) and GLUT-4 (Glucose transporter-4) with respect to glucose transport. Various concentrations of MFMC ranging from 62.5 to 500 μg·mL(-1) were evaluated for glucose uptake activity in vitro using L6 myotubes, rosiglitazone was used as a reference standard. The MFMC showed significant and dose-dependent increase in glucose uptake at the tested concentrations, further, the glucose uptake activity of MFMC (500 μg·mL(-1)) was comparable with rosigilitazone. Furthermore, MFMC has shown up-regulation of GLUT-4 and PPARγ gene expressions in L6 myotubes. In addition, the MFMC when incubated along with cycloheximide (CHX), which is a protein synthesis inhibitor, has shown complete blockade of glucose uptake. This indicates that new protein synthesis is required for increased GLUT-4 translocation. In conclusion, these findings suggest that MFMC is enhancing the glucose uptake significantly and dose dependently through the enhanced expression of PPARγ and GLUT-4 in vitro.

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The study assessed the in vivo antioxidant and hepatoprotective activity of an ethanol (70%) extract of Momordica tuberosa Cogn. (Cucurbitaceae) (TMT) tubers in experimentally induced liver damage by paracetamol (2 g/kg, po.) in albino rats. The degree of protection was ascertained by estimating the levels of biochemical markers like SGPT, SGOT, bilirubin (total and direct), ALP, and triglycerides. Tissue GSH and lipid peroxidation were also determined. The ethanol (70%) extract of tubers in an oral administration of 20 and 40 mg/kg doses produced significant protection by decreasing the activity of serum enzymes, bilirubin, cholesterol, triglycerides and tissue lipid peroxidation, while it increased tissue GSH at 40 mg/kg dose. The effects of the extract were comparable to the standard drug silymarin (100 mg/kg). Results suggested that an ethanol (70%) extract of the tubers of the plant at 40 mg/kg possesses potential hepatoprotective activity against paracetamol-induced hepatic damage and significant antioxidant activity in rats.