Gamma Irradiation-Induced Modulation of the Chemical Profile, Antimicrobial Activity, and Antioxidant Potential of Myrtus communis

Gamma irradiation is one of the potential methods of increasing the biological potential of medicinal and aromatic plants. This paper assessed the impact of gamma irradiation at various doses (5, 15, and 25 kGy) on Myrtus communis L. leaves, using the non-irradiated sample (0 kGy) as a control. The Essential Oil (EO) was obtained by carrying out hydrodistillation using a Clevenger apparatus. Gas chromatography-mass spectrometry was used to analyze the chemical composition of the oils. DPPH, ABTS, and FRAP assays were used to measure antioxidant activity, whereas antibacterial potential was measured against five microbial strains by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The findings showed that gamma irradiation had a strong effect on the chemical composition of the EO, especially by raising the concentration of oxygenated monoterpenes like 1,8-cineole and linalool, and lowering monoterpene hydrocarbons like α-pinene. Antioxidant assays revealed that radical scavenging activity increased in a dose-dependent manner with maximum activity at 25 kGy. Similarly, antimicrobial tests showed better performance of irradiated oils, particularly against Pseudomonas aeruginosa and Bacillus subtilis, since MIC and MBC values were lower at higher doses. These results indicate that gamma irradiation may alter the phytochemical profile and bioactivity of Myrtus communis EO.