Inhibitory effects of an extract of fruits of Physalis peruviana on some intestinal carbohydrases

Physalis peruviana is an Andean specie whose fruits are eaten as food and also has been reported in Colombian folk medicine for diabetes mellitus treatment. In addition, previous pharmacological studies on diabetic Wistar rats, an extract of P. peruviana fruits has been showed antidiabetic activity. In order to deepen in P. peruviana action mode as antidiabetic, in this investigation were determinate the Inhibitory Concentrations 50 (IC50) of P. peruviana fruits crude extract on alpha glucosidase from S. cerevisiae and from intestinal rat powder, on maltase and alpha amylase enzymes. The kinetic behavior of the extract on each enzyme was also investigated, and the enzyme constant (Km) and maximum rate (Vmax) were determined. Extract of fruits of P. peruviana showed different IC50 for alpha glucosidase from S. cerevisiae and intestinal rat powder, suggesting greater affinity for the enzyme of mammalian source (4114.7 and 3552.7 µg/mL, respectively). For maltase, the IC50 was close to that obtained for alpha glucosidase (4191.0 µg/mL) while for alpha amylase, the extract exhibited the highest inhibition (IC50: 619.9 g/mL). Regarding kinetic behavior, the extract showed competitive inhibition on alpha-glucosidase and maltase, and on the non-competitive type of alpha amylase. These suggest that inhibition of intestinal carbohydrases is one of the modes of action for the antidiabetic activity of fruits of P. peruviana.