Humulene

Humulene, commonly referred to as α-humulene, is a naturally occurring monocyclic sesquiterpene with the chemical formula C15H24. It is a major constituent of the essential oil of hops (Humulus lupulus) and is found in a variety of other plants, including cannabis and numerous essential oils. In plants, humulene is produced by the cyclization of farnesyl pyrophosphate through dedicated sesquiterpene synthases.

Structurally, humulene is a hydrocarbon that contributes to the characteristic aroma of hop-derived products. It is valued in perfumery and flavoring for its woody, earthy, and slightly spicy notes, and it can be present as a trail component in beer and other beverages due to its abundance in hops.

Biosynthesis occurs from the common isoprenoid precursor farnesyl pyrophosphate (FPP) via a cyclization reaction catalyzed by humulene synthase enzymes, which convert FPP into the cyclic sesquiterpene framework that characterizes humulene.

In addition to its role in aroma, humulene has been studied for biological activity. Laboratory studies have reported anti-inflammatory and antimicrobial effects, among other activities, but clinical evidence is limited and its pharmacological potential remains an area of ongoing research. As with many essential oil components, humulene is typically used in small quantities in fragrance and flavor applications, and products containing it should be handled with ordinary safety considerations for essential oils.