Ocimene

Aroma and sensory profile

Ocimene is the green, sweet, slightly tropical note that sits on top of basil, lavender, and mango before the heavier terpenes arrive. Fragrance references type it floral with medium strength and describe the mixed-isomer material neat as citrus, tropical, green, terpene, and woody, and its flavor at 40 parts per million as green, tropical, and woody with floral and vegetable nuances [1]. It is lighter and more diffusive than myrcene, its acyclic isomer, and lacks myrcene's musty, resinous base; where myrcene reads like hops and mango skin, ocimene reads like the flower and the green leaf.

The molecule is an acyclic monoterpene with three double bonds, 3,7-dimethylocta-1,3,6-triene, and it has no stereocenter, so there are no enantiomers to compare. What it has instead are geometric isomers around the central double bond, and they do smell different. (E)-beta-ocimene, the trans form that dominates in most plants and in commerce, is described as sweet and herbal [2]. (Z)-beta-ocimene, the cis form, is typed floral and described as warm, floral, herb, flower, and sweet, with a green, tropical, nasturtium-like flavor [3].

Effects and research

No human trial of ocimene was found. The best-known biology of ocimene is ecological, not pharmacological. A 2017 review describes it as a very common plant volatile released in important amounts from the leaves and flowers of many species, acting as a generalist pollinator attractant and as a herbivore-induced signal that recruits the predators and parasitoids of the insects feeding on the plant [4]. Honey bee larvae use it as a hunger pheromone: starving larvae raise their (E)-beta-ocimene output and workers respond by visiting and provisioning the cells [5].

Pharmacological data are recent and animal-based. In rats with adjuvant-induced arthritis, oral ocimene at 50, 100, and 200 milligrams per kilogram for 28 days significantly decreased paw edema and lowered interleukin-1 beta and interleukin-18 while raising glutathione, catalase, and superoxide dismutase [6]. A companion study reported reduced formalin-evoked paw licking, acetic-acid writhing, and carrageenan edema, with gastric protection comparable to omeprazole rather than the mucosal damage typical of standard anti-inflammatory drugs [7].

One inhalation result runs against the calming reputation terpenes usually carry. In a 2026 mouse study comparing two wintersweet flower scents, exposure to the beta-ocimene-rich scent was anxiogenic, particularly in females, reducing light-box exploration and social preference, while the linalool-rich scent did the opposite [8]. It is one study, but it is a reminder that "floral" does not mean sedative.

Natural sources

Ocimene is everywhere in the plant world but rarely the lead compound. The 2017 review calls it one of the most frequent constituents of floral scent across plant families and notes large leaf emissions triggered by herbivory in many species [4]. Fragrance databases record it in basil oil, coriander seed, black currant buds and leaves, elder flower, hop oil, kumquat, lemon leaf, mandarin, mango fruit, marjoram, mint, and a long list of citrus oils [1]; the E isomer is logged in basil oils at 0.31 to 0.76 percent and in curry leaf oil at 7.1 percent [2], and the Z isomer in lavender, bergamot, and geranium oils and in guava at up to 13.6 milligrams per kilogram [3]. In lavender flowers, linalyl acetate and the ocimene isomer mix dominate the volatile fraction [9]. In cannabis it is a minor to moderate terpene in the sweeter, greener chemotypes.

Boiling point and vaporization

PubChem compiles the boiling point of (E)-beta-ocimene as 174 to 175 °C at 760 mmHg and of the Z isomer as 177 °C, both imported from fragrance industry data [10]; the mixed-isomer material is listed at 176 to 178 °C [1]. This profile uses 175 °C (347 °F). That puts ocimene a few degrees above myrcene and just below limonene, in the volatile top-note band. Its practical instability is chemical rather than thermal. With three double bonds, two of them conjugated, ocimene is one of the fastest-reacting terpenes toward atmospheric oxidants, with hydroxyl-radical rate constants measured alongside myrcene and the farnesenes [11], so it fades from an opened basil leaf, hop cone, or lavender bottle within hours to days. No thermal degradation study of ocimene was found.

Safety and regulation

Ocimene is listed by the US Food and Drug Administration as a permitted synthetic flavoring substance at 21 CFR 172.515, as "Ocimene; trans-β-ocimene; 3,7-dimethyl-1,3,6-octatriene" [12]. No cancer classification applies.

Its hazard record is thin, and thin in a reassuring direction. Under Europe's classification inventory, nearly all notifications flag the (E) isomer as a flammable liquid, about half as a skin irritant, and about a third as an eye and respiratory irritant; no majority flags skin sensitization, and only a minority list the aspiration hazard common to the hydrocarbon terpenes [10]. No patch-test series or fragrance-industry safety assessment naming ocimene as a sensitizer was found. The caution that does apply follows from its chemistry: a triene this reactive autoxidizes quickly [11], and the oxidation products of related terpenes are the usual culprits in essential oil allergy. Treat aged basil, lavender, or hop extracts as the exposure to watch on skin.

Industries and uses

Fragrance: ocimene supplies green, sweet, diffusive top notes in floral, herbal, and tropical accords and is stocked in E, Z, and mixed-isomer grades [1][2][3]. Culinary: it holds FDA flavoring status and contributes green, tropical, floral nuances at parts-per-million levels; it is a natural constituent of basil, mango, and citrus flavor [1][12]. Aromatherapy: lavender and basil oils are its carriers; the oxidation caution above applies to aged oils on skin [3][11].