Cryptolepine hydrochloride: a potent antimycobacterial alkaloid derived from Cryptolepis sanguinolenta

The activity of cryptolepine hydrochloride, a salt of the main indoloquinoline alkaloid from the West African medicinal plant Cryptolepis sanguinolenta , was assessed against the fast growing mycobacterial species Mycobacterium fortuitum , which has recently been shown to be of use in the evaluation of antitubercular drugs. The low minimum inhibitory concentration (MIC) of this compound (16 µg/mL) prompted further evaluation against other fast growing mycobacteria namely, M. phlei , M. aurum , M. smegmatis , M. bovis BCG and M. abcessus and the MICs ranged over 2–32 µg/mL for these species. The strong activity of this agent, the need for new antibiotics with activity against Mycobacterium tuberculosis , coupled with the ethnobotanical use of C. sanguinolenta extracts to treat infections, highlight the potential of the cryptolepine template for development of antimycobacterial agents.