BETA-GLUCURONIDASE INHIBITION AND DIURETIC ACTIVITY OF FABIANA-IMBRICATA R-AND-P (SOLANACEAE)

The hydroalcoholic extract of Fabiana imbricata inhibited the enzyme b eta-glucuronidase (beta-gluc) in vitro. Bioassay-guided isolation led to scopoletin as the main active constituent of F. imbricata. Scopolet in was a noncompetitive inhibitor of beta-D-glucuronidase with a K-i v alue of 4 x 10(-5) M. A single oral dose of 250 mg/kg body weight F. i mbricata extract produced a significant increase (p < 0.05) in the uri ne output of rats. The diuretic effect of the extract was weak in comp arison with hydrochlorothiazide at 25 mg/kg. In the acute oral toxicit y study in rats,'Pichi' was shown to be a low toxicity crude drug at d oses 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.