Canarimoic acid: new tirucallane triterpene with antisalmonellal activity from the stem bark of Canarium schweinfurthii Engl.

One new tirucallane triterpene named as canarimoic acid (1), and three known analogues: 3β-hydroxytirucalla-8,24-dien-21-oic acid (2), 3α-acetyltirucalla-8,24-diene-21oic acid (3) and 3-oxotirucalla-8,24-dien-21-oic (4) were isolated from the hydro-ethanolic crude extract of Canarium schweinfurthii. Their structures were established by extensive analysis of 1 D and 2 D NMR data in conjunction with mass spectrometry and by comparison with those reported in the literature. The evaluation of their antisalmonellal activity using broth microdilution method showed that compound 3 was the most active (MIC =16 µg/mL) against Salmonella Typhi and Salmonella Typhimurium followed by compound 1 (MIC= 32 µg/mL) against Salmonella Typhi and Salmonella Enteritidis.