Abstract
The present study reports the isolation of a new flavonol glycoside, 3,5,6,7,8,4′-hexahydroxyflavone-3-O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (1) along with 3,5,6,7,8,4′-hexahydroxyflavone-3-0-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (2), kaempferol-3-O-rutinoside (3) and rutin (4) from the MeOH extract of Aristeguietia discolor (Asteraceae). In addition, five known cinnamic acid derivatives 5–9 were detected in the same extract. The structure of the new glycoside 1 was elucidated by spectral methods including 1D TOCSY and 2D DQF-COSY. The pharmacological activity of the extracts, and some partially purified fractions and pure compounds were studied on the guinea-pig contractions in vitro.