Extracts of Zingiber officinale Rosc. (Ginger) and Curcuma longa Linn. (Tumeric) Rhizomes inhibited Nontuberculous Mycobacteria in vitro

Abstract

Non-tuberculous mycobacteria (NTM) are all the other mycobacteria which can cause pulmonary disease resembling tuberculosis, lymphadenitis, skin disease, or disseminated disease. The antimycobacterial activity of methanol, n-hexane and dichloromethane extracts of Zingiber officinale Rosc. (Ginger) rhizome and extract of Curcuma longa Linn. (Tumeric) were evaluated against four (4) species of nontuberculous Mycobacteria: Mycobacterium abscessus, Mycobacterium smegmatis ATCC 19420, Mycobacterium phlei ATCC 19240 and Mycobacterium fortuitum 684. Susceptibility tests were carried out using the agar well diffusion techniques while agar dilution method was used to determine the minimum inhibitory concentration (MIC). Bactericidal activities of bioactive extracts were evaluated by the viable counting techniques. Dichloromethane extract of Zingiber officinale showed the highest inhibition zone of 16±0.5 and 22±0.00 mm for M. abscessus and M. fortuitum ATCC 684 respectively; and the MIC and MBC for both species of organism were 6.25 mg/mL and 75 mg/mL. The n-hexane and methanol fractions of Zingiber officinale had no activity against tested Mycobacteria species. Also, methanol and n-hexane extracts of Curcuma longa both showed the highest inhibition zone of 16±0.5 and 20±0.0 mm respectively for M. abscessus while the MIC and MBC for both extracts were 25 mg/mL and 75 mg/mL respectively. The kill kinetics of the two plants against susceptible test organisms indicated a dose-dependent bactericidal activity, with decline in population (> 50%) within 4 hours of exposure followed by a total kill (100%) of the population at 8 hours exposure time at doses equivalent to 4 x MIC and 8 x MIC. Thus, it is concluded that this plants may contain compounds with therapeutic activity that could be used in treatment of diseases originating from non-tuberculous mycobacteria infection.

Keyword: Zingiber officinale Rosc. (Ginger), Curcuma longa Linn. (Tumeric), Nontuberculous Mycobacteria,

Antimycobacterial activity, In vitro