Comparative in vitro wound-healing activity of individual and blended black seed, coconut, sesame, and olive oil nanoemulsions

Abstract This study aimed to evaluate and correlate the in vitro wound-healing efficacy of black seed (BS), coconut (COCO), sesame (SMS), and olive (OVO) oils and their corresponding nanoemulsions using a normal human skin fibroblast (NHSF) cell line. The regenerative potential of the oils and their nanoemulsions was comparatively investigated alongside their antioxidant activity. Cytocompatibility was assessed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and acridine orange staining, confirming the non-toxic nature of all tested oils at the applied concentrations. Wound-healing activity was evaluated using a scratch assay. Native oils exhibited moderate wound closure rates of 32.5% and 35.1% for COCO + BS, respectively. In contrast, oil nanoemulsions demonstrated significantly enhanced wound-healing efficacy, achieving closure rates of 48.3%, 51.3% (SMS), 47.8% (COCO), and 27.0% (BS), compared to the untreated control (38.3%). Notably, the combined OVO + SMS formulation achieved a wound closure rate of 40.6%, which improved to 65.3% upon nanoemulsification. Meanwhile, nanoemulsions of the COCO + BS oil mixture resulted in a wound closure rate of 34.7%. Generally, the results indicate that nanoemulsification markedly enhances the wound-healing potential of natural oils, particularly olive and sesame oils. The observed effects are likely attributable to improved bioavailability and antioxidant activity, highlighting COCO and OVO oil-based nanoemulsions as promising natural candidates for wound-healing and regenerative applications.