Chemical profiling, antioxidant, and antimicrobial potential of Algerian thyme, garlic, and lemon essential oils: In vitro and in silico evaluations

Abstract

This study evaluated the potential of essential oils (EOs) from Citrus limon L., Allium sativum L., and Thymus vulgaris L. as natural food preservatives by investigating their chemical composition, antioxidant and antimicrobial activities, and molecular interactions with microbial targets. Gas chromatography–mass spectrometry revealed distinct chemical profiles, with thyme and lemon oils dominated by monoterpenes (95.55% and 98.25%), particularly thymol (42.63%) and D-limonene (74.40%), respectively, whereas garlic oil was characterized by organosulfur compounds (83.16%), mainly diallyl trisulfide (35.94%) and diallyl disulfide (21.59%). In the DPPH assay, thyme oil exhibited the highest radical-scavenging activity (91%), followed by garlic (88%) and lemon (75%) oils, although all showed lower activity than vitamin C and BHT (p < 0.05). Thyme oil demonstrated the strongest antibacterial activity against the tested bacterial strains, particularly Escherichia coli and Staphylococcus aureus, with inhibition zones comparable to gentamicin. Garlic oil showed notable antifungal activity against Candida albicans and Saccharomyces cerevisiae, whereas lemon oil exhibited moderate antimicrobial effects. Molecular docking further indicated favorable interactions of thymol and diallyl trisulfide with S. aureus ParE and C. albicans CYP51, respectively. Overall, the findings highlight the complementary antimicrobial and antioxidant properties of these EOs and support their potential as natural preservatives for food applications.