A review of Zanthoxylum chalybeum Engl: Ethnomedicinal uses, pharmacology, phytochemistry and toxicology

Background: Zanthoxylum chalybeum Engl. is a traditional medicinal plant, which is native to Eastern and Southern Africa. Commonly known as the ‘Knob wood’, it has been used for centuries by several traditional healers in Kenya, Tanzania, Uganda, Zambia and Zimbabwe. The species is very well known to local communities by its common names such as ‘Kundanyoka’ (Shona), ‘Mjafari’ (Swahili) and ‘Ntaleyedungu’ (Uganda), and it grows naturally in the tropics and subtropics. Aim: The present review describes information on the ethnomedicinal uses, phytochemical constituents, pharmacology and toxicology of Z. chalybeum . Method: Collection of data was based on literature research from several sources including electronic databases such as Google scholar, Web of Science, Science Direct, Pubmed, books, book chapters and theses. Results: Z. chalybeum is widely used in the treatment of malaria, cancer and diabetes. Pharmacological studies revealed that crude extracts and some isolated chemical compounds from Z. chalybeum demonstrated biological activities such as antibacterial, antidiabetic and antimalarial activities. Studies in phytochemical analysis of Z. chalybeum revealed the presence of new compounds such as 6-benzo (1, 3) dioxol-5-yl-hexa-2,5 dienoic acid isobutylamide, 4-methoxy-N-(2-methoxy-phenyl)-N methyl-benzamide, N-(2-hydroxy-methyl-propyl)-3 phenyl-acrylamide and 4-(isoprenyloxy)-3-methoxy,4-deoxymethylenedioxyfagaramide. Toxicology studies revealed moderate to high toxicity, depending on the type of cells and the extraction solvent used. Conclusion: Z. chalybeum is a valued medicinal plant used in Eastern and Southern Africa. Contribution: The properties of Z. chalybeum revealed in previous studies can be used to guide research scientists in future drug formulations.