Development of a self-nanoemulsifying system for the oil extract of Mentha spicata L. and evaluation of its anticancer efficacy in vitro

Nanocarriers based on (natural) lipids have been extensively studied to improve the oral bioavailability of anticancer compounds/drugs with poor water solubility. Self-nanoemulsifying drug delivery systems (SNEDDSs) are a route to improve the solubility and bioavailability of lipophilic compounds. In a present study, an SNEDDS using the oil extract of Mentha spicata L. leaves, Tween 80, and PEG 600 (SMO) was prepared. Pseudo-ternary phase diagrams were constructed to find suitable surfactant, solubilizer with the oil extract that form self-nanoemulsion after dilution in water. SMO comprised Tween 80:PEG 600:the oil with 2:3:5 in volume ratios or 2.1:3.4:4.5 in mass ratios. It comprised nanodroplets of 82.5 ± 4.7 nm in diameter and had a stability of >45 days. SMO led to enhanced cytotoxicity of the oil extract with IC-50 values of 1.9 ± 0.1 and 2.0 ± 0.1 mg mL⁻¹ for MDA-MB-231 and MCF-7 cells, respectively. SMO would be applicable for delivery of either water insoluble chemotherapeutic drugs or natural anticancer oils upon more investigations.