A review of ethnobotanical plants that are used for HIV management in Southern Africa

Background

HIV infections are one of the major health issues affecting southern African countries. HIV infections in southern African countries are managed by antiretroviral medications (ARVs) and ethnobotanical plants with anti-HIV properties. The development of HIV viral resistance to current ARVs necessitates the search for new and novel compounds with anti-HIV properties. Southern Africa is rich in biodiversity and phytochemicals with proven anti-viral, bacterial, and fungal properties, and therefore has a good reservoir of novel compounds that can be developed into highly active antiretroviral therapy, or HAART.

Aim of the study

The review aims to survey the literature that reported the use of ethnobotanical plants by traditional healers to treat HIV infections and opportunistic infections caused by HIV (a) without screening for active phytochemicals and (b) coupled with screening using crude extracts, and (c) screening and identification of active phytochemicals.

Materials and methods

Peer-reviewed, original research, and review publications published from 2007 to 2024 were considered in this review. Articles used in this review were searched in Science Direct, Springer Link, PubMed Central, and Google Scholar. Papers were categorized into three groups: plants used or identified by traditional healers and not screened for active phytochemicals; active phytochemicals were screened for active phytochemicals using crude extract; and purified and screened. Other parameters that were identified and noted were the cell types, anti-HIV assays, and toxicity assays that were used to model HIV infection and inhibition, as well as other viral, bacterial, and fungal infections identified in the articles.

Results

Between the years 2018 and 2024, a total of 22 publications and 6264 ethnobotanical plants were reported to be used for treating HIV infections and HIV co-infections in Southern Africa. These numbers are higher than the numbers reported between the years 2007 and 2018 which were 19 publications and a total of 1664 ethnobotanical plants. Most of the publications were survey studies that reported the use of ethnobotanical plants for the management of HIV infections and co-infections without screening and identification of active metabolites followed by survey studies that were coupled with screening of active metabolites using crude extracts. Very few studies went beyond survey studies and used the crude extract to test for the presence of phytochemicals with anti-HIV properties. Only one publication was found that reported the isolation and purification of active metabolite for anti-HIV properties in the year between 2018 and 2024 and only five studies in the years 2007 and 2018. Crude extracts of Croton. dichogamus plant was found to have the lowest IC₅₀ of 0.06 ± 0.01 μg/mL. IC₅₀ of the pure compound was found in the Peltophorum afrianum plant with IC₅₀ of 0.002 μg/ml. The literature review suggests a duplication of efforts and missed opportunities. Multiple publications screened the same plants for anti-HIV properties using identical methodologies and assays. Most of the publications screened for only HIV inhibition while survey studies accompanied the publications identified the use of plants for HIV, fungal, and bacterial infections. Commonly used cell type, HIV assays, and toxicity assays that were used to model HIV infection, progression, and inhibition of phytochemicals were found to be MT-4 cells, MTT assays, and HIV-1 reverse transcriptase enzyme (RT).

Conclusion

Southern Africa has diverse plant species with medicinal properties. These plants contain phytochemicals that interfere with HIV infection to host cells and replication cycles and therefore a potential source of novel molecules that can be potent into potent HIV drugs. More efforts are needed to couple survey studies that report the use of ethnobotanical plants with screening studies that identify the active phytochemicals to ascertain that the plants used by traditional healers do have the "advertised" properties.