Title : Mosquitocidial and mosquito repellent properties of hyptis suaveolens (l.) Poti in Owerri, Imo state
Abstract:
Hyptis suavelons L. Poti, also called Bush Tea, has been widely acclaimed to possess therapeutic and insecticidal activities. The study, a controlled trial investigation used human volunteers to confirm the effectiveness of crude extracts of bush tea oil as a mosquito repellent and adulticidal agent in Owerri, Nigeria. Volatile oil was extracted using petroleum ether as solvent while coconut oil was used as oil base. The study which started by November, 2023 lasted for 8 weeks, made use of 8 volunteers; 4 from Ihiagwa, a rural community and 4 students of the Federal University of Technology, Owerri. Two lotions were made; 20% and 30% by volume of the volatile oil in coconut oil base, with untreated coconut oil as the control. The lotions were applied on exposed body parts of the volunteers. The biting rate, percentage repellence, complete protection time and whole night protection were measured and recorded. Topical application of the treated oil lotions reduced the biting rate of mosquitoes across the two locations, with the 20% (v /v) exhibiting repellent impact of 153 vs 17 and 214 vs 25 in the university community and Ihiagwa community respectively. The 30% (v /v) formulation had the highest percentage repellence of 91.23 % at Location I (Ihiagwa), offered a whole night protection against mosquito also in location I and Complete Protection Time (CPT) of 19.86 and 16.89 respectively across all two locations. There was significant statistical association, r=0.94 (p<0.05) between concentration of the Hyptis suavelens oil formulation and mean duration protection time against mosquitoes. All formulations exhibited adulticidal activities, with the 30% (v /v) formulation exhibiting higher impact, causing fast paralyzing effect on some mosquitoes that were at close range to treated volunteer’s body. The study concludes that volatile oils of Bush Tea grass possess repellent and adulticidal effects, especially at higher concentrations and can be used to reduce human mosquito contacts and hence mosquito-borne diseases and irritation caused by their bites in Nigeria and other African countries.
