The anti-diabetic properties of Guazuma ulmifolia Lam are mediated by the stimulation of glucose uptake in normal and diabetic adipocytes without inducing adipogenesis

Ethnopharmacological importance: Guazuma ulmifolia Lam (Sterculiaceae) is a plant extensively used in Mexico for the empirical treatment of type 2 diabetes. Aim of the study: To investigate the anti-diabetic mechanisms of Guazuma ulmifolia. Materials and methods: Non-toxic concentrations of Guazuma ulmifolia aqueous extracts (GAE) were assayed on adipogenesis and 2-NBDglucose uptake in the murine 3T3-F442A preadipose cell line. Results: GAE added to adipogenic medium (AM) did not affect adipogenesis at any of the tested concentrations (1-70 mu g/ml), whereas in AM lacking insulin GAE 70 mu g/ml induced triglyceride accumulation by 23%. On the other hand, GAE 70 mu g/ml stimulated 2-NBDG uptake by 40% in insulin-sensitive 3T3-F442A adipocytes and by 24% in insulin-resistant adipocytes, with respect to the incorporation showed by insulin-sensitive adipocytes stimulated with the hormone. Conclusion: Guazuma ulmifolia exerts its anti-diabetic effects by stimulating glucose uptake in both insulin-sensitive and insulin-resistant adipocytes without inducing adipogenesis. (C) 2008 Elsevier Ireland Ltd. All rights reserved.