Evaluation of anti-tubercular activity of linolenic acid and conjugatedlinoleic acid as effective inhibitors against Mycobacterium tuberculosis

Objective: To evaluate a new pharmacological activity/effect of linolenic acid(α- and γ-form) and conjugated-linoleic acid(CLA) causing antibacterial activity against Mycobacterium tuberculosis(Mtb). Methods: The anti-Mtb activity/effect of linolenic acid and CLA were determined using different anti-Mtb indicator methods such as resazurin microtiter assay(REMA) and MGIT 960 system assay. The Mtb was incubated with various concentrations(12.5–200) μg/m L of the compounds and anti-Mtb first-line drugs for 5 d in the REMA, and for 3 wk in MGIT 960 system assay. Results: Linolenic acid and CLA obviously indicated their anti-Mtb activity/effect by strongly inhibiting the growth/proliferation of Mtb in a dosedependent manner in the REMA and the MGIT 960 system assay. Interestingly, linolenic acid and CLA consistently induced anti-Mtb activity/effect by effectively inhibiting the growth/proliferation of Mtb in MGIT 960 system for 21 d with a single-treatment, and their minimum inhibitory concentrations were measured as 200 μg/m L respectively. Conclusions: These results demonstrate that linolenic acid and CLA not only have effective anti-Mtb activity/properties, but also induce the selective-anti-Mtb effects by strongly inhibiting and blocking the growth/proliferation of Mtb through a new pharmacological activity/action. Therefore, this study provides novel perspectives for the effective use of them and the potential that can be used as potent anti-Mtb candidate drugs, as well as suggests the advantage of reducing the cost and/or time for developing a new/substantive drug by effectively repurposing the existing drugs or compounds as one of new strategies for the global challenge of tuberculosis.

The anti-tubercular activity of Melia azedarach L. and Lobelia chinensis Lour. and their potential as effective anti-Mycobacterium tuberculosis candidate agents

Objective: To evaluate the anti-mycobacterial activity of Melia azedarach L.(M. azedarach) and Lobelia chinensis Lour.(L. chinensis) extracts against the growth of Mycobacterium tuberculosis(M. tuberculosis).Methods: The anti-M. tuberculosis activity of M. azedarach and L. chinensis extracts were evaluated using different indicator methods such as resazurin microtiter assay(REMA) and mycobacteria growth indicator tube(MGIT) 960 system assay. The M. tuberculosis was incubated with various concentrations(50–800 mg/m L) of the extracts for 5 days in the REMA, and for 4 weeks in MGIT 960 system assay.Results: M. azedarach and L. chinensis extracts showed their anti-M. tuberculosis activity by strongly inhibiting the growth of M. tuberculosis in a concentration-dependent manner in the REMA and the MGIT 960 system assay. Particularly, the methanol extract of M. azedarach and n-hexane extract of L. chinensis consistently exhibited their effects by effectively inhibiting the growth of M. tuberculosis in MGIT 960 system for 4 weeks with a single-treatment, indicating higher anti-M. tuberculosis activity than other extracts,and their minimum inhibitory concentrations were measured as 400 mg/m L and 800 mg/m L, respectively.Conclusions: These results demonstrate that M. azedarach and L. chinensis extracts not only have unique anti-M. tuberculosis activity, but also induce the selective antiM. tuberculosis effects by consistently inhibiting or blocking the growth of M. tuberculosis through a new pharmacological action. Therefore, this study suggests the potential of them as effective candidate agents of next-generation for developing a new anti-tuberculosis drug, as well as the advantage for utilizing traditional medicinal plants as one of effective strategies against tuberculosis.