Formulation and In vivo evaluation of Perovskia abrotanoides Kar. essential oil nanoemulsion incorporated chitosan gel as a novel paradigm in promoting wound healing

Perovskia abrotanoides (P.a) karel , a medicinal plant with antimicrobial, anti-inflammatory, and antioxidant activities, has traditionally been used to heal wounds. The combination of nanoemulsion (NE) formulation and chitosan gel led to improved bioavailability, physical stability, skin penetration, and wound healing properties of drugs. In this study, the wound healing efficiency of P.a essential oil nanoemulsion incorporated chitosan gel was evaluated on Wister rats with circular full-thickness skin wounds. Nanoemulsion containing the essential oil obtained from the flowering branches of Perovskia abrotanoides was formulated by Ultrasonic Emulsification method and loaded into a chitosan 2 % hydrogel ( P .a-NE-loaded chitosan gel). The characteristics of the optimal formulation including particle size, stability, viscosity and antimicrobial activities were investigated. In vivo studies were conducted on Wister rats with circular full-thickness skin wounds, examining the wound-healing process on days 3, 7, 14, and 21. HE and Masson’s trichrome staining were assessed to compare histological changes in the wound region. P.a-NE at pH 5.5 had an average size of 13 ± 0.5 nm, zeta potential of 2.9 ± 0.95 mV, and a quasi-spherical shape confirmed by TEM. It was stable at 4 and 25°C for three months (P < 0.01) and showed quasi-plastic behavior in viscosity analysis. P.a-NE -loaded chitosan gel demonstrated enhanced antimicrobial activity against Staphylococcus aureus , Candida albicans , and Pseudomonas aeruginosa . In vivo studies indicated significant wound improvement (P < 0.05) at day 21 compared to other treatments and the control group. P .a-NE-Loaded chitosan gel can be beneficial as a wound healer because it prevents infections and accelerates wound healing process. • The nanoemulsion containing essential oil of Perovskia abrotanoides ( P.a-NE ) showed a spherical morphology with average size of 13 nm. • The P.a-NE -Loaded chitosan gel exhibited more accelerating wound-healing process compared to essential oil or chitosan alone. • The combination of P.a-NE in chitosan gel has increased the antimicrobial activity (against P. aeruginosa and S. aureus).