In vitro study of ursolic acid combination first-line antituberculosis drugs against drug-sensitive and drug-resistant strains of Mycobacterium tuberculosis

Abstract

Objective: The resurgence of tuberculosis (TB) caused by Mycobacterium TB (MTB) is associated with the rapid spread of multidrug-resistant, therefore, the development of new antimycobacterial agents is necessary. The aim of this study was to evaluate the antimycobacterial activity of ursolic acid (UA) when it using alone and combination with TB drugs. Methods: MTB H37Rv strain, streptomycin-rifampicin resistant strain, and isoniazid-ethambutol resistant strain were evaluated by susceptibility test using a serial number of UA (25-150 µg/mL). Minimum inhibitory concentration (MIC) was read as minimum concentration of drugs that completely inhibit visible growth of organism. Activities of drug combination of UA with TB drug were determined in Lowenstein-Jensen media by calculating the fractional inhibitory concentration index. Results: The results showed that MIC of UA was 50 µg/mL against three different strains of MTB. The combination of UA and TB drugs displayed synergistic interaction, and no antagonism result from the combination was observed for strains of MTB. Conclusion: These results indicate that UA may serve as a promising lead compound for future antimycobacterial drug development.