Formulation and characterization of tea tree and jojoba oils nano-emulgel for in-vivo wound healing assessment

Abstract

Cutaneous wounds are the most common surgical affections among living organisms worldwide, and their healing may be interrupted by several factors. This study aimed to formulate and evaluate the antioxidant, anti-inflammatory, and antimicrobial activity of tea tree and jojoba oils nano-emulsions, additionally, investigating the cytotoxicity of the optimized formula was investigated on normal human lung fibroblast cells (WI-38) by MTT colorimetric assay, additionally its in-vivo wound healing. Nano-emulsions (NEs) were prepared using a high-energy method and characterized by Transmission electron microscopy (TEM), Zeta potential, droplet size, and poly dispersive index (PDI). Nano-emulgel (NEG) was formulated by mixing the standard NE with carbopol® 940. For in-vivo wound healing, thirty adult female albino rats were assigned into control, moist exposed burn ointment (Mebo), and NEG-treated groups. The healing was assessed by analysis of superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and histopathology in healed wound tissues. All formulations demonstrated antioxidant, anti-inflammatory, and antimicrobial activity against Bacillus Subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Enterococcus faecalis, and Candida albicans. The CC₅₀ of the optimized formula was 453.82± 3.87 µg/mL, with a mean droplet size of 105.4 nm and a zeta potential of -39.2 ± 2.1 mV. NEG enhanced wound closure compared to Mebo-treated and control groups. Also, MDA significantly decreased and SOD significantly increased in NEG and Mebo-treated groups compared to the control (p ˂ 0.05). TNF-α, and IL-1β significantly decreased in NEG and Mebo-treated compared to the control (p < 0.05). Histopathology revealed reduced inflammatory cell infiltration, rapid epithelization, and increased collagen deposition in NEG-treated wound tissues compared to the control and Mebo-treated wounds. In conclusion, the NEG containing tea tree and jojoba oils demonstrated significant antioxidant, anti-inflammatory, antimicrobial, and wound healing activities.

Keywords: Antioxidant; Jojoba oil; Nano-emulgel; Tea tree oil; Wound healing.