Mosquito and tick repellency of two

Area of Science:

• Phytochemistry
• Medical Entomology
• Natural Product Chemistry

Background:

• Essential oils (EOs) are aromatic compounds extracted from plants, known for diverse biological activities.
• The Asteraceae family, including Anthemis species, is a rich source of bioactive compounds.
• Mosquitoes (Aedes aegypti) and ticks (Amblyomma americanum) are significant vectors of disease, necessitating effective repellents.

Purpose of the Study:

• To investigate the chemical composition of essential oils from Anthemis melampodina (Am) and Anthemis scrobicularis (As).
• To evaluate the repellent efficacy of Am and As EOs against Aedes aegypti mosquitoes and Amblyomma americanum ticks.

Main Methods:

• Hydrodistillation was used to extract EOs from the aerial parts of Am and As.
• Gas Chromatography-Flame Ionization Detection (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) analyzed EO chemical profiles.
• Laboratory bioassays assessed the repellency of EOs against mosquitoes and ticks, comparing results with DEET.

Main Results:

• The Am EO was primarily composed of α-pinene (17.1%) and β-eudesmol (13.8%), while As EO was dominated by β-eudesmol (12.8%).
• Both Am and As EOs demonstrated repellent activity against Aedes aegypti, with Minimum Effective Doses (MEDs) of 0.187 mg/cm² and 0.312 mg/cm², respectively.
• As EO exhibited greater repellency against nymphal ticks compared to Am EO, though both were less effective than DEET.

Conclusions:

• Anthemis melampodina and Anthemis scrobicularis essential oils possess repellent properties against disease vectors.
• β-eudesmol is a significant component in both analyzed essential oils.
• These findings suggest potential for developing plant-based repellents, although further research is needed to enhance efficacy.