Medicinal plants of Lesotho: A review of ethnomedicinal, pharmacological and conservation studies

Abstract

Background: Of the approximately 2,076 plant species occurring in Lesotho, about 355 are used for medicinal purposes. Many communities in the country, mainly in rural areas with limited access to health facilities, rely on traditional medicine as primary healthcare. Several publications provide helpful information on plants used for medicinal purposes in Lesotho. These include documentation of the plants, investigation of their therapeutic potential to provide scientific validation for their use, and conservation status. However, a synthesis of all the studies conducted so far has hitherto not been undertaken. The current study aimed to provide a systematic review of ethnomedicinal, pharmacological, and conservation studies undertaken on medicinal plants of Lesotho. The synthesis brings together published and unpublished literature sources, thus providing a comprehensive database for studies conducted on Lesotho medicinal plants. Furthermore, it identifies existing knowledge gaps on research that has been carried out on the species and thus provides opportunities for further research, especially in the search for new natural products. Methods: Information was gathered from published and unpublished literature sources, with the earliest publication dating back to 1917. Information was gathered through keyword search using accessible literature sources from Google Scholar, Science Direct, Scopus and PubMed. Books, dissertations, theses, technical reports were also searched. Keywords used for the search were Lesotho, in conjunction with medicinal plant and traditional medicine. To be eligible for inclusion in the current review, a literature source was expected to have assessed ethnomedicinal use, biological/pharmacological activity (e.g., antimicrobial activity), phytochemistry, toxicology) or conservation status of any Lesotho plant species used in traditional medicine. Results: A total of 116 records were identified, of which 76 were included in the review. Thirty-one ethnomedicinal, 14 pharmacological (nine antioxidant, three anti-inflammatory, five antimicrobial activities), six phytochemical, and 15 conservation studies on medicinal plants of Lesotho were scrutinized. It is important to note that some studies evaluated more than one pharmacological activity. Ethnomedicinal studies show that numerous plants are used for medicinal purposes in Lesotho, however studies to scientifically validate their traditional use has remained far behind. Conclusion: Many of Lesotho’s important medicinal plants have been assessed for pharmacological activity, providing scientific proof for their use. However, there are numerous gaps in the number and type of pharmacological and phytochemical studies that have been conducted. These gaps offer endless opportunities for researchers working in these fields. In addition, the conservation status for most of these plants is unknown., therefore, a detailed red data listing of Lesotho plants, particularly those used in traditional medicine, is recommended. Keywords: ailments; ethnomedicine; safety; traditional medicine, treatment toxicology