Constituents of antibacterial extract of Caesalpinia paraguariensis Burk

Abstract

The Argentinean legume Caesalpinia paraguariensis Burk. (Fabaceae) was selected for further fractionation work based on the strong antimicrobial activity of its CH2Cl2-MeOH (1:1 v/v) extract against a host of clinically significant microorganisms, including antibiotic resistant strains. 1D and 2D NMR enabled the identification of the novel benzoxecin derivative caesalpinol along with the known compounds bilobetin, stigma-5-en-3-O-beta-6'-stearoylglucopyranoside, stigma-5-en-3-beta-6'-palmitoylglucopyranoside, stigma-5-en-3-beta-glucopyranoside, oleanolic acid, 3-O-(E)-hydroxycinnamoyl oleanolic acid, betulinic acid, 3-O-(E)-hydroxycinnamoyl betulinic acid, and lupeol from the active fractions. Oleanolic acid was found active against Bacillus subtilis and both methicillin-sensitive and -resistant Staphylococcus aureus with MICs of 8 (17.5 microM), 8 and 64 (140 microM) microg/ml, respectively. The rest of the compounds, however, did not show activity.