Review on the secondary metabolites, biological properties, and ethnomedicinal uses of the component species of the buheri wa afya formula used to treat COVID-19 in Tanzania

•Viral infectious diseases like COVID-19 have shown limited response to current medications necessitating the need for alternative strategies for effective viral infection treatment.•This review explores the chemical composition, biological properties, and ethnomedicinal uses of the constituents of Buheri wa Afya, meaning "good health", a plant-fungi complex formula used in Tanzania for the treatment of COVID-19.•The efficacy in treating COVID-19 patients at different stages of the illness justified the choice of Buheri wa Afya over the other formulations.•This study has highlighted the effectiveness of Buheri wa Afya's constituents in combating COVID-19, citing their antioxidant, anti-inflammatory, antiviral, immunomodulating and other biological properties, which justify its use in Tanzania. It has proven difficult to treat viral infections like SARS-CoV, MERS-CoV, and SARS-CoV-2 that cause severe respiratory disorders with the currently available medications. Alternative strategies for combating viral infections are required to adequately treat infectious diseases like COVID-19. The most potent of them all may be plant-based products or herbal remedies. Following the advent of the COVID-19 epidemic, a number of alternative medicine practitioners in Tanzania developed herbal medicine formulations, claiming that they were effective in treating COVID-19 patients. One among the formulations is Buheri wa Afya, meaning "good health". The rationale for choosing Buheri wa Afya over the other formulations was justified by its efficacy in treating COVID-19 patients at different stages of the illness. This review aimed to collect information on the chemical composition, biological properties, and ethnomedicinal uses of the constituents of Buheri wa Afya formula, a plant-fungi complex formula made of Adansonia digitata L., Ficus sur Forssk, Securidaca longipedunculata Fresen, Syzygium cumini (L.) Skeels, and Zanthoxylum chalybeum Engl., and a fungus, Ganoderma tsugae Murrill, that was and is still used for the treatment of COVID-19 in Tanzania. All information regarding ethnomedical applications, chemical compositions, and biological properties related to the constituents of the herbal formula was collected from PubMed, Research4Life, Google Scholar, Science Direct, Web of Science, Wiley Online Library, Springer, Research Gate link, and published books. The search, which mostly focused on COVID-19 and other viral infectious diseases produced a total of 183 publicat