Résumé
Diabetes mellitus is an important medical-economical-social problem requiring up search for less costly alternatives for treatment, such as use of medicinal plants. Of the species cited in ethnobotanical studies, the "insulin plant" (Myrcia sphaerocarpa DC) appears among those used by diabetics. The objective of this work was to evaluate the inhibitory activity of alpha-amylase by aqueous extracts of "insulin plant", prepared by different methods at a proportion of 1:200 (w:v), for information about the alleged hypoglycemic effect. For this, five samples of commercially teas "insulin plant" were obtained; aqueous extracts were prepared; and thereafter, they were tested for inhibition of alpha-amylase, before and after exposure to simulated gastric fluid. Results demonstrated before exposure to gastric fluid, a significant inhibition of enzyme activity (greater than 50%) in the samples A and C, using the decoction and sample E in all methods of extraction. Comparing methods of extraction, the decoction was more effective. After exposure to gastric fluid, there was a reduction in the activity of enzyme inhibition, suggesting negative influence of low pH on the properties of the inhibitor. These results do not elucidate the mechanism of the hypoglycemic action reported in folk medicine and literature, but indicate a promising path.