Ximenia caffra Sond. (Ximeniaceae) in sub-Saharan Africa: A synthesis and review of its medicinal potential.

ETHNOPHARMACOLOGICAL RELEVANCE: Ximenia caffra Sond. (Ximeniaceae), commonly known as "sour plum" is traditionally used, both topically and orally to treat a wide range of human diseases and ailments such as wounds, sexually transmitted infections (STIs), infertility, stomach ache, fever, eye problems, diarrhoea, bilharzia, menorrhagia, malaria, intestinal worms, impotence and coughs. The bark and fruits are used by small-scale farmers as ethnoveterinary medicine to treat dermatophilosis, foot rot, saddle sores and control ectoparasites. Oil from X. caffra seed is traditionally used as a moisturiser, soap and shampoo for dry, fragile and damaged hair.

AIM OF THE REVIEW: The aim of this study was to comprehensively summarize the research that has been done on the botany, ethnomedicinal uses, phytochemistry and biological activities of X. caffra in different locations throughout its geographical range in the sub-Saharan African region so as to understand its importance and potential in primary healthcare systems.

MATERIALS AND METHODS: This study was carried out using a comprehensive and systematic literature search on the ethnomedicinal uses, phytochemistry and biological activities of the species throughout its distributional range. Literature sources included papers published in international journals, reports from international, regional and national organizations, conference papers, books and theses. PubMed and Scopus, search engines such as Google Scholar and online collection ScienceDirect were used.

RESULTS: This study showed that X. caffra is used as traditional medicine in 83.3% of the countries in tropical Africa where it is indigenous. A total of 65 human and animal ailments and diseases are recorded for X. caffra, with a high degree of consensus for wounds, sexually transmitted infections (STIs), infertility, stomach ache, fever, eye problems, diarrhoea, bilharzia, menorrhagia, malaria, intestinal worms and coughs. Phytochemical investigation of X. caffra revealed that the species has various compounds including flavonoids, phenols, phytosterols, tannins and fatty acids. Different plant parts, aqueous and organic extracts exhibited anti-amoebic, antibacterial, antifungal, anti-inflammatory, antioxidant, antiparasitic, antiproliferative, HIV-1 reverse transcriptase (RT) inhibitory, insecticidal, non-mutagenic and toxicity activities.

CONCLUSION: In this review, the ethnomedicinal uses, phytochemistry, biological activities and toxicity of different extracts and compounds of X. caffra have been summarized. Although many of the ethnomedicinal uses of X. caffra have been validated by phytochemical and pharmacological studies, there are still some gaps where current knowledge could be improved. There are very few to nil experimental animal studies, randomized clinical trials and target-organ toxicity studies involving X. caffra and its derivatives that have been carried out so far. At the present moment, there is not sufficient evidence to interpret the specific chemical mechanisms associated with some of the documented biological activities of the species. Therefore, future studies should identify the bioactive components, details of the molecular modes or mechanisms of action, pharmacokinetics and physiological pathways for specific bioactives of X. caffra.