Antimicrobial Activity of 6-Paradol and Related Compounds

The seeds of Aframomum melegueta K. Schum. (Zingiberaceae) yielded 6-paradol (1) and 6-shogaol (2) as the major antimycobacterium agents, based on a bioactivity-guided fractionation. These isolates were found to be active against Mycobacterium chelonei, M. intracellulare, M. smegmatis and M. xenopi (MIC 10-15 µg/ml). Derivatives were prepared in an attempt to define some of the structural parameters needed for antimicrobial activity. The desmethyl derivative of 1 retained the antimycobacterial activity and was found to be more active against Candida albicans than 1 and 2. Gingerone (9), not previously reported in this source, was found to be inactive. The identity of the compounds were confirmed by spectral analyses (UV, IR, NMR, and EIMS) and by comparison with reported data.