Mosquito-repellent activities of a north central Nigeria local Hyptis suaveolens Essential oil and its toxicity evaluation in mice

Abstract

Aim: Mosquito-repellent activities of Hyptis suaveolens essential oil (EO) obtained from Kwara State, north central Nigeria; and its toxicity in mice were evaluated.

Materials and Methods: Hyptis suaveolens plants were collected from University of Ilorin premises. Fresh leaves were weighed, pound, hydrodistilled and the EO characterised using GCMS. Mosquitoes (female anopheles and culex) 150 were bred from larva stage in the laboratory against which the repellency activities were determined. Fifteen (15) adult mice with the average weight of (25 ±2.21 g) were randomly assigned into three (3) groups (A-C), of five (5) mice each. Daily administration of distilled water, EO 100 mg/kg body weight and 500 mg/kg body weight were done oropharyngeally for seven days to groups A, B and C respectively. The mice were sacrificed, and the blood, liver and kidney of the animals were collected. Blood, tissues, and serum parameters were assayed for in the mice.

Results: Caryophyllene oxide, caryophyllene, spathulenol, alloaromadendrene, benzaldehyde and bornanone were some of the compounds confirmed present in the EO. The EO in water (1:99) is 100% efficacious, for up to 60 minutes. The EO induced significant increase (p<0.05) the blood levels of WBC, RBC, HCT, HGB in all treated groups. Serum albumin, total and direct bilirubin, and the total protein in all the treated groups were significantly reduced while no significant difference in the activities of ALP, ALT and AST in the liver, kidney and serum of treated groups occurred when compared with the control. The levels of the serum urea and creatinine, increased significantly in all the treated groups (p<0.05).

Conclusion: The Hyptis suaveolens essential oil possesses mosquito-repellent activities but may cause adverse on the enzymatic and haematological, liver and kidney functions at 500 mg/kg body weight in mice.