Chemical composition, antioxidant properties, antibacterial, and antifungal activities of essential oils from three basil cultivars in Jordan Valley

Ocimum basilicum L. (basil) is an extensively cultivated aromatic herb characterized by essential oils (EOs) recognized for various biological properties. This study examined the chemical composition of EOs from three basil cultivars (O. basilicum var. minimum, sweet, and Genovese) cultivated in the Jordan Valley and assessed their antioxidant and antimicrobial properties, particularly focusing on antifungal efficacy against eight phytopathogenic fungi. EOs were obtained using hydrodistillation and subsequently determined via GC–MS, and their antioxidant activity was evaluated using the DPPH assay, whereas the antibacterial and antifungal effectiveness was ascertained by minimum inhibitory concentration (MIC) experiments. The O. basilicum var. minimum EO was primarily composed of linalool (45.77%) and methyl chavicol (30.11%), whereas sweet basil EO had E-methyl cinnamate (61.15%). Genovese basil exhibited compositional variations between fresh and dried leaves, with linalool and methyl chavicol predominating in fresh leaves, whereas E-methyl cinnamate was predominant in dried leaves. The antioxidant activity varied from IC50 value of 71.10 ± 3.55–149.41 ± 7.47 µg/mL, with Genovese basil exhibiting the most potent radical scavenging activity. Antimicrobial experiments demonstrated MIC values ranging from 3.125 to 100 µg/mL, with Genovese basil displaying the greatest antibacterial potency. Seven fungal isolates demonstrated susceptibility to the tested oils, with MIC values of 50 and 100 μg/mL, exceeding the inhibitory efficacy of the positive controls, bleach and phenol. The studied basil EOs demonstrate unique chemotypes and significant antioxidant and antibacterial properties, positioning O. basilicum var. Genovese as a viable natural antimicrobial agent for food preservation and agricultural use.