Chitosan nanoparticles containing Elettaria cardamomum and Cinnamomum zeylanicum essential oils; repellent and larvicidal effects against a malaria mosquito vector, and cytotoxic effects on a human skin normal cell line

Malaria is still a public health concern, with around half-million deaths annually. On the other hand, excessive use of chemical insecticides led to resistance in mosquitoes and environmental pollutions. In this study, compounds of essential oils of Elettaria cardamomum and Cinnamomum zeylanicum were first identified. Chitosan nanoparticles containing each essential oil were then prepared using the ionic gelation method. The repellent effect of the essential oils and as-prepared nanoformulations was in the range of 3–34 min, compared to DEET (N, N-diethyl-meta-toluamide) with a protection time of 62 ± 5 min. Moreover, chitosan nanoparticles containing E. cardamomum and C. zeylanicum essential oils with particle sizes of 204 ± 10 and 178 ± 7 nm induced 100% larval mortality against Anopheles stephensi at 25 µg.mL−1 concentration; their LC50 values were obtained at 7.58 and 2.98 µg.mL−1. Interestingly, the nanoformulations showed no cytotoxicity on the human skin normal cell line, HFFF2. The prepared nanoformulations could thus be used as extremely effective and safe larvicides against the malaria mosquito vector.