Phytochemical Analysis and Antimicrobial Activity of Medicinal Plants Commonly Used in the Treatment of Tuberculosis in the Eastern Free State, South Africa

Abstract

Background: Tuberculosis (TB), an airborne infectious disease that mainly infects the lungs, caused by Mycobacterium tuberculosis. South Africa is one of the countries with the highest TB and multi-drugresistant TB burden. Objective: This study aimed at screening eight medicinal plants that are frequently used by herbalists and traditional healers of the eastern Free State for the treatment of TB. Methods: Thirty-two plant extracts were screened for the presence of phytochemicals, antibacterial, antifungal and antimycobacterial activities using standard methods. Results: Extracts prepared from Hermannia depressa and Senecio harveianus displayed the best antibacterial activity against all test microorganisms ranging between 0.098 and 0.781 mg/ml while Drimia depressa and Lotononis lanceolata extracts displayed the best antifungal activity between 0.049 and 0.781 mg/ml. The good antimycobacterial activity was observed with organic extracts prepared from Dicoma anomala, H. depressa, L. lanceolata and S. harveianus between 0.195 and 0.781 mg/ml. Discussion: All plants displayed the presence of tannins and saponins and the absence of alkaloids, anthraquinones and steroids. Plants under this study demonstrated significant antibacterial, antifungal and antimycobacterial activities, with extracts prepared from H. depressa and S. harveianus displaying the best activity against all the test microorganisms with MIC values ranging between 0.098 and 0.781 mg/ml, respectively. Conclusion: The selected medicinal plants that are used in the treatment of TB and related respiratory ailments in the eastern Free State revealed the presence of phytochemicals and significant antimicrobial activities, which explain and justify their frequent use by traditional healers.