Hypoglycemic, vasorelaxant and hepatoprotective effects of Cochlospermum vitifolium (Willd.) Sprengel:: A potential agent for the treatment of metabolic syndrome

Cochlospermum vitifolium (Willd.) Sprengel is a Mexican medicinal plant that is used in the folk medicine for the treatment of hypertension, diabetes, hepatitis and related diseases. The purpose of the present study was to assess the pharmacological properties of different extracts from Cochlospermum vitifolium bark as potential agent for the treatment of some factors related with metabolic syndrome (MS), a complex disease produced for several pathophysiological factors such as visceral fat obesity, insulin resistance, hypertension, dyslipidernia and liver steatosis. Hexane (HECv), dichloromethane (DECv) and methanol (MECv) extracts were subjected to some pharmacological assays to determine their vasorelaxant and hypoglycemic activity. On the other hand, MECv was also evaluated to determine its hepatoprotective effect on sub-chronic experimental assay. HECv showed a significant endothelium-independent relaxation on rat aorta rings (intact endothelium: IC50 = 14.42 +/- 5.90 mu g/mL, E-max = 92.71 +/- 8.9%; denuded endothelium: IC50 = 27.94 +/- 4.0 mu g/mL, E-max = 78.68 +/- 4.6%) and MECv produced an endothelium-dependent relaxation (IC50 = 21.94 +/- 6.87 mu g/mL, E-max = 79.12 +/- 7.80%) on this tissue. Furthermore, HECv (at a dose of 120 mg/kg) also showed a significant decrease of blood glucose levels (p < 0.05) on normoglycemic rats. Moreover, MECv (at a dose of 100 mg/kg) also was administered to bile duct-obstructed rats to determine its hepatoprotective activity, showing a statistically significant decrease of serum glutamic-pyruvic transaminase (PGT, 45%) and alkaline phosphatase (APh, 15%) (p < 0.05). Finally, we obtained a crystalline polyphenolic compound from MECv by spontaneous precipitation. Those crystals were identified as (+/-)-naringenin by X-ray diffraction, NMR, IR and GC-MS techniques. Results suggest that Cochlospennum vitifolium could be used as a potential agent against MS since it shows hypoglycemic, vasorelaxant and hepatoprotective properties. (c) 2006 Elsevier Ireland Ltd. All rights reserved.