2025/08/18 by Nyasvisvo, David Singleton, Sithole, Rudo, Sande, Shadreck +1
paper · doi:10.48347/imist.prsm/ajmap-v11i2.56015
Adansonia digitata L., Vitex payos (Lour.) Merr., and Peltophorum africanum Sond. are traditionally used by communities in malaria-endemic parts of Mazowe district, Zimbabwe to repel host-seeking mosquitoes. The study aimed to identify phytochemicals with proven mosquito repellent activities from selected parts of these plants. Shade-dried plant samples of A. digitata fruit shells, V. payos leaves, and P. africanum leaves were ground into fine powder and extracted using methanol. The extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). Phytochemicals were identified by matching their retention time and mass spectral fragmentation patterns with known compounds recorded in the National Institute of Standards and Technology library. Principal component analysis (PCA) and K-means clustering were used to analyze data on the plants’ phytochemicals percentage peak area. The phytochemicals' repellent activities were confirmed from the literature. GC-MS revealed 54 phytochemicals across seven structural classes, with terpenes/terpenoids (23) and fatty acids (14) being the most abundant. Oleic acid dominated all three extracts (11.2-26.6% peak area). Fourteen compounds in V. payos, twelve in P. africanum, and seven in A. digitata showed literature-confirmed repellent/insecticidal activity against different mosquito species. PCA demonstrated distinct chemoprofiles, with V. payos contributing most to variance (PC1 loading: 0.995). Key phytochemicals included linoleic acid, phytol, caryophyllene oxide, and germacrene D. This study provides the first chemical validation of traditional use, identifying multiple mosquitocidal phytochemicals in these plants. The abundance of fatty acids and terpenoids supports their potential for developing plant-based repellents. Future studies should isolate these compounds for efficacy testing and formulation development.