Origanum oil

Chemical properties

Origanum oils are produced from the flowering herb of Mediterranean Origanum (Lamiaceae) species, mainly Origanum vulgare L. ssp. hirtum. Spanish origanum oil is derived from Coridothymus capitatus Rchb., syn. Thymbra capitata (L.) Cav. The oils differ mainly in their content of carvacrol and thymol, which are major constituents. Oil with a high carvacrol content is a yellowish-red to dark brown liquid with a spicy, herbaceous odor, reminiscent of thyme.The color quickly turns to blackwhen in contact with iron.
d²⁰₂₀ 0.930–0.955; n²⁰_D 1.500–1.513; α²⁰_D ?5 ° to +2 °; solubility: 1 vol in ≤4 vol of 70% ethanol; solutions may become opalescent. Composition: ??-terpinene 3.5–10%; p-cymene 5.5–9%, thymol 0–5%, carvacrol 60–75% (Spanish type).
Annually, some 10 t each of Spanish origanum oil and of O. vulgare oil are produced, the latter mainly in Hungary. Origanum oils are used in perfume compositions for herbal, spicy, leathery notes and in seasoning mixtures.

Chemical properties

Mexican oregano is, for all practical purposes, organoleptically indistinguishable from the species Origanum vulgare L. or Coleus ambionica. Thus, the name oregano is a general term applying to a particular herb flavor, rather than to a particular species of plant. Oregano is a perennial herb that is either common or wild and is a vigorous grower with oval leaves on stems up to 30 in. high. It has purple flowers that appear in late summer. The part used is the leaf.

Occurrence

Found in the herb Thymus capitatus Hoffmgg. et Link and various other species of Origanum (Fam. Labiatae).

Preparation

By steam distillation of the flowering herb.

Definition

Extractives and their physically modified derivatives. Thymus capitatus, Labiatae.

Essential oil composition

Screening of antimicrobial activity compounds in Lippia graveolens showed that most of compounds were flavonoids mono- and dihydroxylated in the B ring.* Volatile oil from oregano contains carvacrol.

Safety Profile

Poison by skin contact. Moderately toxic by ingestion. A severe skin irritant. When heated to decomposition it emits acrid smoke and irritating fumes. See also CARVACROL