What is "humulene"

n. A naturally-occurring monocyclic sesquiterpene found in the essential oils of ''Humulus lupulus'' (hops).

Humulene, also known as α-humulene or α-caryophyllene, is a naturally occurring monocyclic sesquiterpene (CH), containing an 11-membered ring and consisting of 3 isoprene units containing three nonconjugated C═C double bonds, two of them being triply substituted and one being doubly substituted. It was first found in the essential oils of Humulus lupulus ( hops), from which it derives its name. Humulene is an isomer of β-caryophyllene, and the two are often found together as a mixture in many aromatic plants.