Myxaoside A, a new triterpenoid saponin from <i>Cordia myxa</i> L. (Boraginaceae)

Abstract

The phytochemical study of <i>Cordia myxa</i> L. led to the isolation, through chromatographic techniques, of a new triterpenoid saponin, 3-<i>O</i>-[<i>α</i>-<i>L</i>-rhamnopyranosyl-(1→3)-(6-<i>O</i>-acetyl-<i>β</i>-<i>D</i>-glucopyranosyl)]-22<i>β</i>-hydroxyolean-12-ene (<b>3</b>) namely Myxaoside A, together with three known compounds, Soyasaponine I (<b>1</b>), oleanolic acid (<b>2</b>), and 3-<i>O</i>-acetyl-oleanolic acid (<b>4</b>). All structures were established, based on 1 & 2D-NMR spectroscopic analysis and comparison with previous published reports. Compound <b>1</b>-<b>4</b> were evaluated for their antibacterial activity on various strains of bacteria including <i>Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae</i> and <i>Vibrio cholerae</i>. It appears that compounds <b>1</b> and <b>3</b> were active on all the tested microbial species, while compounds <b>2</b> and <b>4</b>, shown no significant effect on <i>S. aureus</i> and <i>K. pneumoniae</i> at low concentrations 6.5 mg/mL and 3.0 mg/mL.