Solid-lipid nanoparticles (SLN)s containing Zataria multiflora essential oil with no-cytotoxicity and potent repellent activity against Anopheles stephensi.

Malaria is still a global health concern with more than 400,000 death annually. Personal protection using mosquitoes' repellent is an effective prevention strategy, especially in endemic areas. The toxic effects of synthetics repellents and their adverse effects on fabricated goods have made the development of green repellent critical. In this study, ingredients of Zataria multiflora essential oil (ZMEO) were identified using GC-MS analysis. Solid-lipid nanoparticles containing ZMEO (1%) were prepared (SLN-ZMEO) using the high-pressure homogenizer method. The repellent activity of ZMEO and SLN-ZMEO was investigated using Klun and Debboun method and compared together. Besides, their cytotoxicity on a human skin normal cell line (HFFF2) was evaluated. Five major components of ZMEO were carvacrol (27.05%), thymol (26.452%), γ-terpinene (15.144%), o-cymene (13.584%), and α-pinene (9.483%). The SLN-ZMEO showed a spherical shape with a particle size of 134 ± 7 nm. Moreover, their polydispersity index (PDI), zeta potential and entrapment efficiency were determined as 0.24 ± 0.1, - 9.82 ± 0.95 mV and 64.6 ± 3.8%, respectively. Interestingly, the protection time of nanoformulation (93 ± 5 min) was three times longer than that of the non-formulated essential oil (29 ± 2 min). Interestingly, both samples did not show cytotoxicity on HFFF2. Therefore, the prepared nanoformulation can be used as a green and potent repellent.