Selected Zingiberaceae Species Exhibiting Inhibitory Activity Against Mycobacterium tuberculosis H37Rv: A Phytochemical Profile

As part of the research efforts to identify plant species which may have potential against tuberculosis, a study was earlier conducted in collaboration with the institute for TB Research, university of illinois, Chicago, to randomly screen the crude alcoholic extracts of different plant species using the MABA assay, to determine any inhibitory activity against the causative agent, Mycobacterium tuberculosis H37Rv. of the five species belonging to the family Zingiberaceae, four were found to inhibit the growth of M. tuberculosis H37Rv. These species included Alpinia purpurata (Vieill.) K. Schum., Alpinia zerumbet (Pers.) B.l.Burtt. & R.M. Sm., Etlingera elatior (Jack) R.M. Sm. and Zingiber officinale Roscoe. Each species was collected in bulk and subjected to extraction and several bioassay-directed chromatographic fractionations. The pure constituents obtained were analyzed for their structure using spectroscopic techniques. The bioactivity of the pure isolates, as minimum inhibitory concentration values, was likewise determined. The results showed the antitubercular activity to be present in the nonpolar extracts. Structure elucidation of the pure isolates revealed the presence of sterols (ß-sitosterol, stigmasterol), sterol derivatives (ß-sitosteryl-ß-dgalactoside, ß-sitosteryl-3-o-6’-palmityl-ß-d-glucoside), phenyldecanoids (6-shogaol and 6-gingerol) and a flavonoid (kumatakenin). determination of the MiC showed higher activity of the phenyldecanoids than the steroids, the steroidal derivatives and the flavonoid.