The antimycobacterial activity and potential herb-drug interactions of selected South African plants

Abstract

Tuberculosis (TB) has plagued humanity for centuries, ranking as one of the leading causes of death globally. It surpasses even HIV/AIDS in mortality caused by a single infectious biological agent. Since 1997, the World Health Organization (WHO) has released an annual report on tuberculosis worldwide. Recent data from 2021 estimates that approximately 10.6 million individuals contracted TB, and this number steadily increased compared to previous years. Numerous public health strategies have saved millions of lives across different regions; however, progress remains modest while cases resistant to drugs continue to rise. The global decline rate in tuberculosis incidence stood at only 1.5% in 2017 but must increase significantly – by around ten times – before reaching the target set forth by WHO's End TB Strategy by the year 2025. In addition to these challenges, efforts made toward reducing the burden of TB face setbacks due to the COVID-19 pandemic. In 2020 alone, the number of people dying from tuberculosis was predicted to rise by 0.2 – 0.4 million (World Health Organization, 2020). Hence, it is imperative to explore novel methods and sources of remedies.

Plants have long been recognized as valuable sources of medicine and have been extensively studied in literature and research. Medicinal plants such as aspirin, ephedrine, morphine, digoxin, and atropine have played a significant role in the history of medicine and drug discoveries (Gilani & Atta-ur-Rahman., 2005). The global market for herbal medicines was valued at approximately US $83 billion in 2019 and is projected to reach US $550 billion by 2030. Herbs are plant-based substances used in medicine for their scent, taste or medicinal properties. Herbal remedies are popular health supplements that aim to treat illnesses and enhance overall well-being (insightSLICE.,2021). One emerging trend is the simultaneous use of herbal remedies alongside conventional medications. Herb-drug interactions may be more common than drug-drug interactions due to pharmaceuticals typically being composed of isolated chemical compounds, while natural herbal products contain multiple active phytochemicals with pharmacological effects. Fugh-Berman & Ernst (2001) emphasized thoroughly evaluating herb-drug interactions when treating patients to optimize therapeutic outcomes without any potential harm. Many tuberculosis patients often turn towards using herbal remedies; however, there exists insufficient information regarding these potentially risky combinations within various databases. Moe et al.(2018) argue that it is crucial we provide clinicians with comprehensive knowledge about herb–drug interactions. This would enable them to offer accurate advice and avoid any negative impacts on the effectiveness of prescribed pharmaceutical treatments.