Repellent efficacy of the nanogel containing Acroptilon repens essential oil in comparison with DEET against Anopheles stephensi

Abstract

Objective: Malaria is a vector-borne disease that causes many deaths worldwide; repellents are a practical approach to malaria prevention, especially in endemic regions. Results: Gas chromatography-mass spectrometry analysis was used to identify compounds in Acroptilon repens essential oil (EO). Alpha-copaene (15.67%), α-cubenen (3.76%), caryophyllene oxide (14.00%), 1-heptadecane (5.61%), and δ-cadinene (2.84) were five major compounds. After that, the nanoemulsion containing the EO with a particle size of 46 ± 4 nm, SPAN 0.85, PDI 0.4, and zeta potential − 5.7 ± 0.4 mV was prepared. Then, it was gellified by adding CMC (carboxymethyl cellulose) to the nanoemulsion. Besides, ATR-FTIR analysis (Attenuated Total Reflection-Fourier Transform InfraRed) was used to confirm the EO’s successful loading in the nanogel. Finally, the protection time and repellent activity of nanogel compared to DEET (N, N-diethyl-meta-toluamide) were investigated against Anopheles stephensi. Interestingly, the nanogel with a protection time of 310 ± 45 min was significantly more potent than DEET (160 ± 17 min). It could thus be considered for future investigation against other mosquitoes.