Development of a gelatin-based delivery system for Citrus medica essential oil to improve antioxidant and antibacterial efficacy against burn pathogens

Background: Burns are one of the most common accidents that mainly because of the ongoing war daily burn injuries occur due to bombings and landmines in many areas. Burn infections often result in fatal outcomes due to multidrug resistant bacteria, especially Staphylococcus aureus. The main objective of this research was to determine the antibacterial and antioxidant properties of Citrus medica essential oil before and after polymerization with natural polymer gelatin, for enhancing their biological activity against resistant S. aureus isolates. Methods: From March 2024 to July 2024; during which 120 swab samples were obtained from Iraqi patients' suffering from wound and burn infections. The emergence of bacterial resistance has emphasized the need to find new sources of antibacterial agents, including natural products like essential oils. S. aureus strains were isolated and identified with the Vitek 2 system. Sensitivity to the antibiotics was determined by disc agar diffusion method. The MICs of C. medica EOs and gelatin polymer were assessed by the agar dilution assay. Antioxidant activities of both compounds were analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) by free radical scavenging assay. Results: Of the tested S. aureus isolates, strains 1, 6, 8, 20, 22 and 30 showed the maximum resistance towards antibiotics. The MIC values of C. medica essential oil and its gelatin polymer were 40,000 ppm against the resistant bacteria isolates. In the DPPH assay, gelatin polymer presented a higher anti-oxidative activity than the essential oil. Conclusion: the antibacterial and antioxidant activities of C. medica oil and gelatin polymer were significant. The polymerization increased the antioxidant activity of the oil, which might be used as a natural alternative for treatment of antibiotic-resistant S. aureus infection.