Antimicrobial potential of mentha spp. essential oils as raw and loaded solid lipid nanoparticles against dental caries

Objective: This study evaluates the antimicrobial potential of Mentha spp. (M. spicata L., M. xpiperita L. and M. pulegium L.) essential oils as raw and loaded solid lipid nanoparticles (SLNs)against dental caries. Design: Essentials oils extraction from fresh aerial parts of Mentha spp. was carried out using hydro distillation technique. Solid lipid nanoparticles of Mentha essential oil were prepared by w/o/w type double emulsification method. The antimicrobial activity of both pure Mentha spp. essential oils and Mentha spp. SLNs was determined against bacteria presented in saliva collected from 12 patients using agar diffusion assay. Results: Mentha spp. essential oils loaded solid lipid nanoparticles (MSLNs) were spherical shaped with sizes ranged from 111 to 202 nm and with PDI from 0.43 to 0.76, EE% between 85 and 88, and ZP of −11.8 to -40 mV. Antimicrobial results showed that MSLNs exhibited higher in vitro antimicrobial activity than pure Mentha spp. essential oil. Particularly, with an inhibition zone of 20 mm. These both MSLNs were even more active than the reference compound novobiocin. Conclusion: Our findings demonstrate that Mentha spp. essential oils as a nanostructure increase the efficiency of these natural products as antibacterial agents against caries.