In vitro antimycobacterial activity of medicinal plants Lantana camara, Cryptolepis sanguinolenta, and Zanthoxylum leprieurii

Naasson Tuyiringire; Ivan Taremwa Mugisha; Deusdedit Tusubira; Jean-Pierre Munyampundu; Claude Mambo Muvunyi; Yvan Vander Heyden

doi:10.1016/j.jctube.2022.100307

In vitro antimycobacterial activity of medicinal plants Lantana camara, Cryptolepis sanguinolenta, and Zanthoxylum leprieurii

J Clin Tuberc Other Mycobact Dis. 2022 Mar 3:27:100307. doi: 10.1016/j.jctube.2022.100307. eCollection 2022 May.

Authors

Naasson Tuyiringire^{1

2}, Ivan Taremwa Mugisha³, Deusdedit Tusubira⁴, Jean-Pierre Munyampundu⁵, Claude Mambo Muvunyi⁶, Yvan Vander Heyden⁷

Affiliations

¹ Pharm-BioTechnology and Traditional Medicine Centre (PHARMBIOTRAC), Department of Pharmacy, Mbarara University of Science & Technology, P. O. Box 1410, Mbarara, Uganda.
² School of Nursing and Midwifery, College of Medicine and Health Sciences, University of Rwanda, KG11 Ave, 47St/P.O. Box 3286, Kigali, Rwanda.
³ Institute of Applied Health Sciences, Clarke International University, P.O. Box 7782, Kampala, Uganda.
⁴ Department of Biochemistry, Mbarara University of Science and Technology, P. O. Box 1410, Mbarara, Uganda.
⁵ School of Science, College of Science and Technology, University of Rwanda, KN 67 Street Nyarugenge, P.O. Box 3900, Kigali, Rwanda.
⁶ College of Medicine and Health Sciences, University of Rwanda, KG11 Ave, 47St/P.O. Box 3286, Kigali, Rwanda.
⁷ Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090 Brussels, Belgium.

Abstract

Background: Imperative need exists to search for new anti-TB drugs that are safer, and more effective against drug-resistant strains. Medicinal plants have been the source of active ingredients for drug development. However, the slow growth and biosafety level requirements of M. tuberculosis culture are considerable challenges. M. smegmatis can be used as a surrogate for M. tuberculosis. In the current study, preliminary phytochemical screening and antimycobacterial activity evaluation of crude methanolic extracts of medicinal plants against M. smegmatis, and two M. tuberculosis strains, were conducted.

Materials and methods: Crude methanolic extracts, obtained from the leaves of L. camara, roots of C. sanguinolenta, and stem barks of Z. leprieurii, were tested for antimycobacterial activity against M. smegmatis (mc²155), pan-sensitive (H37Rv), and rifampicin-resistant (TMC-331) M. tuberculosis, using visual Resazurin Microtiter Assay (REMA) on 96 well plates. Preliminary qualitative phytochemical screening tests were performed using standard chemical methods.

Results: The three methanolic extracts inhibited mycobacterial growth in vitro. They were more active against rifampicin-resistant strain with MICs of 176, 97, and 45 µg/mL for L. camara, C. sanguinolenta, and Z. leprieurii extracts, respectively. The lowest activity was observed against M. smegmatis with MICs of 574, 325, and 520 µg/mL, respectively. Against H37Rv, activity was intermediate to those of TMC-331 and mc²155. However, L. camara extract showed the same activity against H37Rv and M. smegmatis. Preliminary phytochemical analysis revealed alkaloids, flavonoids, phenolic compounds, saponins, tannins, and terpenoids.

Conclusions: Leaves of L. camara, roots of C. sanguinolenta, and stem barks of Z. leprieurii exhibit antimycobacterial activity against M. smegmatis, pan-sensitive, and rifampicin-resistant M. tuberculosis. This offers the possibilities for novel therapeutic opportunities against TB including multidrug-resistant TB. Further investigations on safety and mechanisms of action are required. These studies could be done using M. smegmatis as a surrogate for the highly pathogenic M. tuberculosis.

Keywords: C. sanguinolenta; In vitro activity; L. camara; M. smegmatis; M. tuberculosis; Medicinal plants; Minimum inhibitory concentration; Resazurin microtiter assay; Z. leprieurii.