Antiplasmodial, antimycobacterial, and cytotoxic principles from Camchaya calcarea.

Chemical exploration of Camchaya calcarea (family Compositae) has led to the isolation of nine known sesquiterpene lactones 1 - 9, together with caffeic acid methyl ester 10. Sesquiterpenes 1, 2, 3, 4, 5, 7, and 8 exhibited moderate antiplasmodial activity, but showed potent antimycobacterial activity. Interestingly, the cytotoxicity of sesquiterpene lactones 1, 2, and 4 towards small-cell lung cancer cell line (NCI-H187) is stronger (two orders of magnitude) than towards the Vero cell line. Caffeic acid methyl ester (10) was cytotoxic against NCI-H187 and BC cell lines, however the ester 10 showed only mild antimycobacterial activity.