Mosquito repellent propensity of hexane extract of <i>Cymbopogon citratus</i> Stapf. (Poaceae), lemongrass, cream and emulgel formulations

Malaria is a global threat affecting majorly the African continent with Nigeria having the highest burden of deaths from the disease. Prophylactic measures in addition to curative treatments are strategies used for eradication of malaria. This study aims to develop topical mosquito repellent from lemongrass (Cymbopogon citratus). Lemongrass extract was obtained by Soxhlet extraction using n-hexane, it was formulated as lemongrass extract cream (LGCM) and emugel (LGEM) at 1 and 2% w/w concentrations. Organoleptic properties, spreadability, pH and skin irritation test were evaluated. Percentage mosquito repellency (R) and complete protection time (CPT) assay using the animal (rodent) model were determined and compared with N, N-diethyl-meta-toluamide (DEET). Results showed all the formulations were non-gritty, homogenous, relatively stable upon storage for 30 days at room temperature except forLGCM 1. They were non-irritant to the skin; pH was in range of 5.3 – 8. Spreadability was optimum with LGCM, LGEM 1 and 2% w/w. Mosquito repellency was concentration dependent and ˃ 80% in LGCM 2 and LGEM 2 but emulgels exhibited better repellency. CPT was 4, 5 and 8h for LGCM 2, LGEM 2 and DEET respectively. This study shows that LGEM 2% may be considered as an efficient topical mosquito-repelling formulation.