Management of Diabetes Mellitus and Hypertension by the Yorubas in Southwest Nigeria: An Inventory of Useful Ethnobotanicals

The prevalence and consequential mortality rate of diabetes mellitus and hypertension are concerning; thus, this study explored the traditional knowledge of medicinal plants used in their management by the Yoruba people of Southwest Nigeria. A descriptive cross-sectional survey was conducted across the six states of the region, involving 180 respondents, comprising herb sellers and traditional medicine practitioners. Using structured questionnaires and key informant interviews, data were documented and analysed with the aid of descriptive statistics, inferential statistics and ethnobotanical indices, viz, Use Value (UV), Relative Frequency of Citation (RFC), and Cultural Importance Index (CII). Fifty-five (55) plant species belonging to 36 families were identified, with Fabaceae and Apocynaceae being predominant. Leaves were the most commonly utilised plant part (43–54%). Frequently cited and culturally significant species included Picralima nitida, Aristolochia ringens, Gymnanthemum amygdalinum, Rauwolfia vomitoria, Pyrus communis, and Garcinia kola. While the Use Value (UV) differed among states (p ­≤ 0.05), RFC and CII values were consistent, indicating shared ethnomedicinal traditions. Herbal Knowledge was primarily passed down within families, with women serving as the principal custodians. The majority of respondents advocated for collaboration between traditional and modern healthcare systems and emphasized conservation through cultivation and government protection. The study underscores the ethnobotanical richness of the region and its potential contribution to healthcare and biodiversity management. It provides a baseline for phytochemical and pharmacological validation of priority species and advocates for integration of validated herbal remedies into complementary healthcare systems and conservation frameworks.