Harnessing antimicrobial and antioxidant-rich emulsions from citronella (Cymbopogon nardus) oil enriched with plant extract mixture for effective wound healing

Plant essential oils with remarkable antimicrobial, and antioxidant properties have been used for decades in treating various skin ailments. However, their high volatility and cytotoxicity limit their efficacy as therapeutic agents compared to synthetic medications. To overcome such limitations, the present study investigates the bioactive potential of emulsion formulated from citronella essential oil with an oil-surfactant-water ratio of 88:6:6 wt%. Additionally, a plant extract mixture prepared from methanolic extraction of six different medicinal plants was also incorporated to prepare plant-extract loaded emulsions and was evaluated for their bioactivities. The antimicrobial activities of all emulsions against wound pathogens exhibited a bactericidal nature with the highest zone of inhibitions in the range of 18 ± 0.18 – 21 ± 0.08 (S. aureus) and 19 ± 0.05 – 25 ± 0.02 (C. albicans). The emulsions also exhibited potent scavenging activities and reduced 95 % of dermatophyte (Trichophyton mentagrophytes) growth within 7 days. Accelerated stability studies and thermal analysis data indicated their resilience against phase separation. Cytotoxicity analysis on HaCaT cells showed IC50 concentration from 0. 1983 ± 0. 0016 µl/ml to 0. 4685 ± 0. 0022 µl/ml. Furthermore, an in vitro scratch wound healing assay on HaCaT cells showed 98 % cell migration in 24 h, highlighting their wound healing potential.