How do basil's essential oils exert their notable antimicrobial activity?

By inhibiting the growth of certain bacteria and fungi

The essential oils contained within basil demonstrate significant biological activity against microscopic organisms, manifesting as antimicrobial properties. This capability is inherent to the plant, serving as a natural defense mechanism in the garden against potential microbial threats. In the context of human health potential, this translates to the documented ability of basil extracts to actively inhibit the proliferation and growth of specific strains of bacteria and fungi. This property is what drives exploration into using basil oil for topical applications or as a natural food preservative, although this internal use is secondary to medically recommended infection treatments.