Antimicrobial and Antioxidant Activity of Essential Oils Treated by Gamma Irradiation Extracted from Citrus Peels.

Orange and lemon peels was used as a source for essential oil (EO). Gamma radiation at does (0, 2, 4, 6, 8 and 10 kGy) were submitted to essential oils then essential oils were analyzed for their physicochemical properties and for chemical composition using GC/MS. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and Ferric-reducing antioxidant power (FRAP) were measured to examine the antioxidant activity of essential oils. Agar-well diffusion method was used to estimate antimicrobial activity. Chromatographic examination revealed that the primary constituent of orange and lemon peels EO was d-limonene. Antioxidant activity was significantly increased when essential oils were exposed to increasing levels of gamma irradiation up to 4 kGy. DPPH and FRAP values at 4 kGy were (51.16 and 76.81%) and (246.28 and 661.54 µM TE/mg) of orange and lemon peels EO, respectively. The maximum inhibition zone was shown with essential oils irradiated at a dose 4 kGy. Our study showed that lemon essential oils had the best antioxidant and antimicrobial activities compared to orange essential oils.