Antibacterial activity of a triterpenoid saponin from the stems of Caesalpinia pulcherrima Linn.

A new compound 1 was isolated from the methanolic extract of the stems of the Caesalpinia pulcherrima Linn. along with a reported compound (2) 3-O-beta-D-glucopyranosyl-(1 -> 4)-beta-D-xylopyranosyl-(1 -> 3)-alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyl hederagenin 28-O-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl ester. The new compound 1 has m.p. 272-274 degrees C, m.f. C46H74O17, [M](+) m/z 898. It was characterised as 3-O-beta-D-glucopyranosyl-(1. 4)-alpha-L-arabinopyranosyl hederagenin 28-O-beta-D-xylopyranosyl ester by various colour reactions, chemical degradations and spectral analyses. Antibacterial activity of compound 1 was screened against various Gram-positive and Gram-negative bacteria and showed significant results.