Cecropia obtusifolia Bertol and its active compound, chlorogenic acid, stimulate 2-NBDglucose uptake in both insulin-sensitive and insulin-resistant 3T3 adipocytes

Ethnopharmacological importance: Cecropia obtusifolia Bertol (Cecropiaceae) is a plant extensively used for the empirical treatment of type 2 diabetes in Mexico. Although some of its hypoglycemic principles have been described, their mechanisms of action remain unclear. Aim of the study: To investigate the anti-diabetic mechanisms of Cecropia obtusifolia aqueous extract (CAE) and its active compound chlorogenic acid (CGA). Materials and methods: Non-toxic concentrations of CAE and CGA were assayed on the adipogenesis and 2-NBDglucose uptake in 3T3-F442A murine adipocytes. Results: Added to adipogenic medium, CAE 70 mu g/ml induced a modest increment (20%) in 3T3 adipogenesis whereas CGA did not affect adipogenesis at any of the tested concentrations (0.1 - 100 mu M). Both preparations stimulated 2-NBDG uptake in adipocytes by 51% (CAE) and 176% (CGA) in the absence of insulin, and by 174% (CAE) and 404% (CGA) in the presence of the hormone. CAE and CGA also stimulated the 2-NBDG uptake in insulin-resistant 3T3 adipocytes by 35% and 141%, respectively, compared with the incorporation shown by insulin-sensitive adipocytes stimulated by the hormone. The potency of CGA to stimulate 2-NBDG uptake was comparable to the anti-diabetic drug rosiglitazone. Conclusion: Cecropia obtusifolia and CGA exert their anti-diabetic effects stimulating glucose uptake in both insulin-sensitive and insulin-resistant adipocytes without appreciable pro-adipogenic effects. (c) 2008 Elsevier Ireland Ltd. All rights reserved.