Comparable efficacy of carvacrol-containing nanogel to DEET as standard mosquitoes’ repellent

Aim and Background: Malaria with a half-million deaths annually is still a major public health concern. Anopheles stephensi is the major vector of malaria in Iran, and it distributed in Middle east, Indian peninsula, and even China. Especially in endemic regions, using repellents is a practical approach to preventing such diseases. In addition to the side effects of synthetic repellents, resistance to them is also common due to frequent use. Attempts to development of natural repellents using nanotechnology has received much attention in recent years Methods: In this study, nanoemulsions containing carvacrol, was first prepared. The nanoemulsion weas then gellified by adding carboxymethyl cellulose (CMC). Besides, viscosity and successful loading were investigated using viscometry and Attenuated Total Reflection-Fourier Transform InfraRed (ATR-FTIR) analyses. After that, the complete protection time of the nanogel compared to DEET (N, N-diethyl-meta-toluamide) was evaluated against the A. stephensi. Results and discussion: The repellent activity of commercial DEET (40% w/v) was 480 ± 30 min; interestingly, nanogel-containing carvacrol (2.4% w/v) showed 470 ± 17 min protection time. The straightforward, repeatable preparation method and no need for advanced devices are some advantages of the developed nanogels. Conclusion: Results suggested that nanogel, could be considered novel natural repellents against A. stephensi and other species of vector mosquitoes