Repellency Effects and Chemical Components of Essential Oils Foeniculum Vulgare and Cinnamomum Verum against Aedes Vexans in Iran

The presence of different climatic conditions in Iran has resulted in the high richness of medicinal plants. The occurrence of adverse side effects was reported following use of the chemical-based repellents which extensively used for personal protection against nuisance mosquitoes. All the efforts are made for exploring new repellents originated from medicinal plants and could be protected safe and whole night against biting arthropods. This will be an effective action for preventing of risk of arthropod-borne diseases.

The fennel seeds and cinnamon bark were chosen due to antibacterial, antioxidant and insecticidal properties. The essential oils were obtained using hydro-distillation using a Clevenger-type apparatus. The chemical components of essential oils were determined by gas chromatography-mass spectrometry. A well-colonized Aedes vexans in insectary was used for repellency assays on the animal model (the white rabbit).

Eighteen and 15 components were identified in the essential oils of fennel and cinnamon and Cadina-1,4-diene and b-Oplopenone were respectively as the main components. The protection time of 50% essential oils was assessed against lab-bred Aedes vexans, and protection time were estimated 3 and 3.5 h for F. vulgare and 1 and 1.5 h for C. verum,. According to a dose-response analysis, the median effective dosage (ED50) of essential oils was 13.7 and 84.2 μl/cm2 for F. vulgare and C. verum.

The essential oil of F. vulgare could provide acceptable protection against dengue fever vectors on the animal subject. It is recommended to be continued the investigation on human volunteers against other medically important arthropods.