Holy basil (Ocimum tenuiflorum), also known as Tulsi, produces an essential oil dominated by eugenol, (E)-β-caryophyllene, and methyl eugenol—phenylpropanoid and sesquiterpene constituents with documented antioxidant and pesticidal properties. The oil exhibits potent larvicidal activity against disease-transmitting mosquitoes (LC50 15-56 μg/mL) and strongly inhibits acetylcholinesterase,^[1] activities consistent with its eugenol-rich profile and longstanding use in Ayurvedic medicine.