Combined Cytotoxic Effects of Carvacrol-Based Essential Oil Formulations

Carvacrol, a phenolic monoterpene predominantly found in Origanum species, has been reported to exhibit antimicrobial, anti-inflammatory, antioxidant, and cytotoxic effects. Formulations such as Vacrol and S-Mix, enriched with carvacrol and complementary essential oil compounds, may enhance therapeutic efficacy while reducing toxicity. Essential oil components were analyzed via GC-MS. Cell viability was assessed using the sulforhodamine B (SRB) assay at different concentrations and incubation periods. An in ovo chorioallantoic membrane (CAM) assay was performed to investigate tumor volume changes and histopathological alterations. Vacrol and S-Mix demonstrated concentration- and time-dependent cell viability-attenuating effects in MDA-MB-231 cells, with significant reductions in viability at higher concentrations (1–10 mM). In ovo, S-Mix induced ~40% reduction in tumor volume and promoted apoptotic morphology compared to controls. Combined effects of carvacrol with α-pinene, eugenol, and β-terpineol likely contributed to enhanced bioactivity. These findings support further preclinical and mechanistic investigations to validate their therapeutic potential.