Exploring African Medicinal Plants for Potential Tuberculosis Treatments

Jenn Hoskins
26th June, 2024

Exploring African Medicinal Plants for Potential Tuberculosis Treatments

Study found that fractions from the bulb of the medicinal plant Crinum asiaticum (pictured) demonstrated the most potent antimycobacterial activity of all species tested, identifying it as a key source for potential new tuberculosis drug leads.

Photographer: Jean-Paul Boerekamps

Key Findings

  • The study by the University of Pretoria explored medicinal plants from Ghana and South Africa for their potential to fight drug-resistant TB
  • Crinum asiaticum (bulb) was identified as the most potent plant, showing strong activity against non-pathogenic Mycobacterium species
  • Specific fractions of Crinum asiaticum also showed moderate activity against the infectious M. tuberculosis strain, suggesting potential for new TB treatments
The emergence of drug-resistant strains of Mycobacterium tuberculosis (M. tuberculosis) presents a significant threat to global health, underscoring the urgent need for new chemotherapeutic agents. A recent study conducted by the University of Pretoria investigates the antimycobacterial properties of medicinal plants from Ghana and South Africa, aiming to discover novel compounds that could potentially combat these resistant strains[1]. Historically, natural products have been a rich source of new drugs, including the rifamycins, which are crucial in tuberculosis (TB) treatment[2]. The renewed interest in natural products is driven by the growing incidence of multidrug-resistant TB (MDR-TB) and the adverse effects associated with current TB drugs. This study aligns with previous research that emphasizes the need for innovative approaches to TB drug discovery[2]. The study evaluated 36 plant extracts and their 252 corresponding solid phase extraction (SPE) generated fractions against non-pathogenic Mycobacterium species, specifically Mycobacterium smegmatis and Mycobacterium aurum. These species serve as models due to their non-pathogenic nature and similarity to M. tuberculosis in terms of drug susceptibility. The most potent fraction was further tested against the infectious M. tuberculosis strain. Crinum asiaticum (bulb) from the Amaryllidaceae family emerged as the most potent plant species. Specific fractions of this plant showed exceptional activity against the non-pathogenic Mycobacterium species with minimum inhibitory concentrations (MICs) ranging from 0.39 µg/ml to 25 µg/ml. One fraction exhibited moderate activity against M. tuberculosis with an MIC of 32.6 µg/ml. Metabolomic analysis identified eight compounds predicted to be active against M. smegmatis and M. aurum. This study provides valuable insights into the antimycobacterial properties of Ghanaian and South African plants, highlighting the potential of Crinum asiaticum as a source of new antimycobacterial agents. The findings are particularly relevant given the global burden of latent TB infection (LTBI), which affects approximately 1.7 billion people[3]. Addressing this latent reservoir is crucial for achieving the End TB Strategy's goal of eliminating TB by 2050[3]. Furthermore, the study's focus on natural products aligns with the need for new and novel antitubercular leads to combat the increasing incidence of MDR-TB. In 2018, the United Nations High-Level Meeting (UNHLM) on tuberculosis declared DR-TB a global public health priority, emphasizing the need for bold targets and innovative solutions[4]. Despite progress in some high-burden countries, the COVID-19 pandemic has posed significant challenges to DR-TB care, making the discovery of new drugs even more critical[4]. The prevalence of drug-resistant TB, including MDR and extensively drug-resistant (XDR) TB, remains a significant concern. In South Africa, for instance, the prevalence of rifampicin-resistant TB nearly doubled between 2001-02 and 2012-14, highlighting the need for new therapeutic options[5]. The current study's identification of active compounds from Crinum asiaticum offers a promising avenue for developing new treatments to address these resistant strains. In conclusion, the University of Pretoria's study underscores the potential of medicinal plants from Ghana and South Africa in the fight against TB. By identifying specific fractions of Crinum asiaticum with potent antimycobacterial activity, the research provides a foundation for future work focused on isolating and evaluating these compounds. Such efforts are essential to combat the global threat of drug-resistant TB and achieve long-term public health goals.

MedicineBiochemPlant Science

References

Main Study

1) Investigation of the antimycobacterial activity of African medicinal plants combined with chemometric analysis to identify potential leads.

Published 25th June, 2024

https://doi.org/10.1038/s41598-024-65369-7

Related Studies

2) Current perspectives in drug discovery against tuberculosis from natural products.

https://doi.org/10.1016/j.ijmyco.2015.05.004

3) The Global Burden of Latent Tuberculosis Infection: A Re-estimation Using Mathematical Modelling.

https://doi.org/10.1371/journal.pmed.1002152

4) Situational analysis of 10 countries with a high burden of drug-resistant tuberculosis 2 years post-UNHLM declaration: progress and setbacks in a changing landscape.

https://doi.org/10.1016/j.ijid.2021.06.022

5) Prevalence of drug-resistant tuberculosis and imputed burden in South Africa: a national and sub-national cross-sectional survey.

https://doi.org/10.1016/S1473-3099(18)30222-6


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