Phytochemical and Pharmacological Studies of Guettarda acreana

Abstract

The present study examines the effects of the extracts [petroleum ether, CHCl₃, CHCl₃/MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Guettarda acreana on the electrically induced contractions (E.C.I.) of the isolated guinea-pig ileum. The results of the experiments indicate that CHCl₃/MeOH (9:1), MeOH extract, and the MeOH soluble part from CHCl₃/MeOH extract tested at concentrations of 1.2, 2.5, and 5 µg/ml, dose-dependently reduced the guinea-pig ileum contractions. Furthermore, some partially purified fractions I-IV from the MeOH extract, each tested at the same concentrations of the extracts, and some pure compounds (6 × 10^-6, 3 × 10^-6, 1 × 10^-6 M) isolated from the above fractions significantly reduced, in a dose-dependent manner, the electrical contractions of the ileum. The active compounds were identified as the known indole alkaloids strictosidic acid, lyalosidic acid, 5α-carboxystrictosidine, strictosidine, and sickingine, as well as the known quinic acid derivatives 5-caffeoylquinic acid, 4,5-dicaffeoylquinic acid, and shikimic acid by spectral data. Two known quinovic acid glycosides and a new triterpenic glycoside, quinovic acid 3β-O-α-rhamnopyranosyl-(1→3)-(β-glucopyranosyl-(1→6)-β-glucopyranoside, were also isolated and their structures established by NMR and MS data.

Key words

Guettarda acreana - Rubiaceae - indole alkaloids - qunic acid derivatives - quinovic acid glycosides - electrical contractions - guinea-pig ileum - antispasmodic