A nanoemulsion-based nanogel of Citrus limon essential oil with leishmanicidal activity against Leishmania tropica and Leishmania major.

Cutaneous leishmaniasis is one of the diseases that severely affects human skin. Nanogels are the well-known formulation for topical drug delivery due to easy usage, high loading capacity, and physical and chemical stabilities. In this study, the toxicity effect of three essential oils, including Mentha piperita, Anethum graveolens, and Citrus limon (CLEO), was evaluated against Leishmania major and Leishmania tropica. Ingredients of CLEO as the most potent essential oil were identified using GC-MS analysis. The five major components were limonene (61.83%), sabinene (16.99%), trans-limonene oxide (3.08%), cis-limonene oxide (2.27%), and 1,2-cyclohexane diol, 1-methyl-4-(1-methylethenyl) (1.50%). The nanogel of CLEO (CLNgel) was prepared by the addition of carbomer 940 (1% w/v) to the prepared nanoemulsion with a droplet size of 146 ± 12 nm. The viscosity of CLNgel was fitted with a regression of non-Newtonian materials, Carreau-Yasuda. Interestingly, CLNgel at a concentration of 80 µg/mL reduced the viability of both species to 0%. Therefore, the prepared prototype can/could/would be used as an excellent nanoformulation for in vivo studies.