Triterpenoid saponins from the fruit pulp of <i>Tetrapleura tetraptera</i> (Fabaceae)

Abstract

<i>Tetrapleura tetraptera</i> fruit, used as spice in West Africa was studied chemically; five previously undescribed triterpenoid saponins <b>1</b>-<b>5</b> and four known compounds <b>6</b>-<b>9</b> were isolated from the <i>n</i>-Butanol fraction. The chemical structures of all nine isolates were determined by comprehensive analysis of HRMS, 1D & 2D NMR experiments and by comparison with data in the literature. All nine compounds were evaluated for antibacterial activity by the broth microdilution through the rapid <i>p</i>-iodonitrotetrazolium chloride (INT) colorimetric technique. The results showed that only compounds <b>5</b> (MIC = 64 µg/mL against <i>P. aeruginosa</i> and <i>P. stuartii</i>) and <b>8</b> (MIC = 64 µg/mL against <i>E. coli</i>) exhibited moderate antibacterial activity. The rest of the compounds displayed weak antibacterial activity against the tested organisms. Molecular docking studies was used to comprehend antibacterial activities.