Nootkatin is a naturally occurring organic compound classified as a sesquiterpenoid with the molecular formula . The compound belongs to the nootkatone family of natural products derived from grapefruit and other citrus sources, distinguished by its special structure featuring multiple double bonds, cycloheptatriene ring, and a ketone functional group. Nootkatin was initially isolated in 1952 from the steam-volative oil of the heartwood of yellow cedar by Carlsson et al.
Nootkatin occurs as a minor component in the essential oils of grapefruit (Citrus paradisi) and Alaskan yellow cedar (Callitropsis nootkatensis), formed via oxidative degradation of nootkatone. Biosynthetically, the compound is formed from farnesyl pyrophosphate through cyclization pathways typical of sesquiterpenes, with enzymatic oxidation yielding the ketone functionality.
The compound is also found in such taxons as Juniperus communis, Juniperus thurifera, Juniperus osteosperma, Juniperus taiwaniana, Cupressus torulosa, among others.
Nootkatin displays diverse bioactivities, including potential antimicrobial, antiinflammatory, and insect-repellent properties akin to nootkatone, which is a biopesticide against ticks and mosquitoes.