Evaluation of the Repellent Activity of Essential Oils Extracted from Some Selected Medicinal Plants in Ethiopia Against Adult Anopheles Arabienasis Patton (Diptera: Culicidae) Under Laboratory Conditions
| dc.contributor.advisor | Emana Getu | |
| dc.contributor.advisor | Araya Gebresilassie | |
| dc.contributor.author | Tilanew Getie | |
| dc.date.accessioned | 2025-09-05T23:09:15Z | |
| dc.date.available | 2025-09-05T23:09:15Z | |
| dc.date.issued | 2022-04 | |
| dc.description.abstract | Mosquitoes are vectors of several important pathogens and parasites, including malaria, which is transmitted by a bite of an infected female mosquito of the genus Anopheles. Malaria remains the leading cause of morbidity and mortality around the world mainly in sub-Saharan African countries including Ethiopia. Even though different controlling methods of malaria vectors have been used, it becomes more difficult to malaria expansion due to the rapid resistance development of mosquitoes to insecticides and synthetic repellents. Toxic reactions of the chemicals have also been reported in some circumstances. Therefore, this study was designed to evaluate the repellent efficacy of six selected traditionally used medicinal plants including Citrus limon, Kleinia odora, Securidaca longepedunculata, Warburgia ugandensis, Rosmarinus officinalis, and Lavandula angustifolia as repellents against Anopheles arabiensis in Ethiopia. Also, to evaluate dermal and oral toxicity on animals.Plant parts were collected from different parts of the country. Essential oils (EOs) were extracted using Clevenger hydro distillation by heating at 120 0C.. Serial dilutions of each plant repellent were made with ethanol and tested to identify an effective dose range and tested on volunteers using laboratory-reared An. arabienasis. 5% and 10% (W/V) ointment were formulated by combining 0.25 and 0.5 mls of EOs in 5 g of petroleum jelly respectively for skin irritation assessment Skin irritation was examined on adult guinea pigs using half a gram of 5% and 10% EO ointment of W.ugandensis since it was found to have the best repellent effect. Acute oral toxicity was also tested on albino mice at different concentrations of W. ugandensis essential oils. At 5% (W/V) concentration, W. ugandensis showed lowest ED50 (0.019%) and ED95 (0.410%) values against An. arabiensis showing the highest repellent activity among the candidate plants. While, S. longepedunculata scored the least repellent power. However, no significant difference was observed in all plants for both doses. Essential oils of all plants had >89% mosquito repellant ability for 2.5 hours and W. ugandensis lasted its complete repellent power for up 4 hours. Skin irritation assessment of W. ugandensis essential oils showed the absence of any dermal effect. However, an acute oral toxicity test showed the presence of some symptoms like diarrhea, drowsiness, and erection of fur starting from the doses of 2400 mg/Kg body weight of mice, and death was observed at 4800 mg/Kg seven days after treatment. Significant body weight loss was also observed at the dose of 4800 mg/Kg. This showed a slight toxicity effect of the oils extracted from the leaves of the plant. In general, essential oils from all the plants under study showed to have remarkable mosquito repellent power although variation was observed in between. Possibilities to stabilize the essential oils for their prolonged repellent effect should be developed by changing the type of solvents used. Further studies on the optimization of doses for repellency tests and does for skin irritation should be conducted. | |
| dc.identifier.uri | https://etd.aau.edu.et/handle/123456789/7390 | |
| dc.language.iso | en_US | |
| dc.publisher | Addis Ababa University | |
| dc.subject | An. Arabiensis | |
| dc.subject | Essential Oils | |
| dc.subject | Malaria | |
| dc.subject | Mosquito Repellents | |
| dc.title | Evaluation of the Repellent Activity of Essential Oils Extracted from Some Selected Medicinal Plants in Ethiopia Against Adult Anopheles Arabienasis Patton (Diptera: Culicidae) Under Laboratory Conditions | |
| dc.type | Thesis |