β-glucuronidase inhibition and diuretic activity ofFabiana imbricata R. & P. (Solanaceae)

Abstract

The hydroalcoholic extract of Fabiana imbricata inhibited the enzyme β-glucuronidase (β-gluc) in vitro. Bioassay-guided isolation led to scopoletin as the main active constituent of F. imbricata. Scopoletin was a noncompetitive inhibitor of β-D-glucuronidase with a K i value of 4 × 10 −5 M. A single oral dose of 250 mg/kg body weight F. imbricata extract produced a significant increase (p < 0.05) in the urine output of rats. The diuretic effect of the extract was weak in comparison with hydrochlorothiazide at 25 mg/kg. In the acute oral toxicity study in rats, «Pichi» was shown to be a low toxicity crude drug at doses up to 5 g crude extract/kg body weight. At concentrations up to 0.50 mg/mL, the crude extract did not increase the number of chromosome aberrations in the in vitro human lymphocyte assay