Antimycobacterial compounds from Piper sanctum

Bioassay-guided chromatographic separation of the antimycobacterial extract of the leaves of Piper sanctum afforded 14 new compounds, identified as 2-oxo-12-(3',4'-methylenedioxyphenyl)dodecane (1), 2-oxo-14-(3',4'-methylenedioxyphenyl)tetradecane (2), 2-oxo-16-(3',4'-methylenedioxyphenyl)hexadecane (3), 2-oxo-18-(3',4'-methylenedioxyphenyl)octadecane (4), 2-oxo-14-(3',4'-methylenedioxyphenyl)-trans-13-tetradecene (5), 2-oxo-16-(3',4'-methylenedioxyphenyl)-trans-15-hexadecene (6), 2-oxo-18-(3',4'-methylenedioxyphenyl)-trans-17-octadecene (7), 2-oxo-16-phenyl-trans-3-hexadecene (8), methyl [6-(10-phenyldecanyl)tetrahydropyran-2-yl]acetate (9), methyl 2-(6-tridecyltetrahydro-2H-pyran-2-yl)acetate (10), methyl 2-(5-tetradecyltetrahydro-2-furanyl)acetate (11), 2-oxo-14-(3',4'-methylenedioxyphenyl)-trans-3-tetradecene (12), 2-oxo-16-(3',4'-methylenedioxyphenyl)-trans-3-hexadecene (13), and 2-oxo-16-phenyl-3-hexadecane (14). In addition, p-eugenol (15), methyleugenol (16), Z-piperolide (17), demethoxyyangonin (18), 5,6-dehydro-7,8-dihydromethysticin (19), cepharanone B (20), piperolactam A (21), cepharadione B (22), N-trans-feruloyltyramine (23), and N-trans-(p-coumaroyl)tyramine (24) were obtained from the anti-TBC stem extract of the plant. GC-MS and HPLC analyses of the essential oils of the leaves and stem revealed that safrol (25) was the major component of the oils. Compounds 2, 3, 6, 18-21, and 24 inhibited the growth of Mycobacterium tuberculosis when tested by the MABA assay, with MIC values ranging from 4 to 64 microg/mL.