Isolation of 6-, 8-, and 10-gingerol from ginger rhizome by HPLC and preliminary evaluation of inhibition of Mycobacterium avium and Mycobacterium tuberculosis

Diseases caused by Mycobacterium avium (M. avium) and Mycobacterium tuberculosis (M. tuberculosis) have reached pandemic proportions with some strains being resistant to existing chemotherapies. Complex therapies requiring four to six drugs are sometimes required to prevent the emergence of resistant strains. There is a need for the discovery of new drugs or compounds that are potential drug templates that can be used to treat diseases caused by these bacteria. The research reported in this paper describes the isolation of 6-, 8-, and 10-gingerol from fresh ginger rhizome and the identification of 10-gingerol as the most active inhibitor of M. avium and M. tuberculosis in vitro. The gingerols were isolated by fractionation of a crude methylene chloride extract of fresh ginger rhizome by normal phase HPLC. Identification was based on mass spectral data. The identification of 10-gingerol was confirmed by synthesis.