Pharmacognosy with the Basics of Plant Biochemistry - Kovalyov V. M. 2004

Special Part
Essential Oils
Monoterpenes and Monoterpenoids

Monoterpenes and their oxygenated derivatives are widely distributed in the free state and form an integral part of Essential Oils. They are formed from two C5 units According to the HEAD-to-tail isoprene rule. Monoterpenes are classified based on the number of rings into acyclic, monocyclic, and bicyclic.

Acyclic monoterpenes belong to the 2,6-dimethyloctane type and may contain three, two, or one double bond. They are represented by Hydrocarbons (myrcene and its isomer ocimene), alcohols (geraniol, linalool, citronellol), aldehydes (citral, citronellal), and others.

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Variants of the geraniol formula representation

Monocyclic monoterpenes belong to the p-menthane type. Among unsaturated hydrocarbons of the menthane type, limonene, a-, ß-, and y-terpinene, as well as a- and ß-phellandrene, are the most widespread.

Oxygen-containing menthane derivatives are frequently found in essential oils: alcohols (menthol, terpineol), ketones (menthone, pulegone, carvone), oxides (cineole), and peroxides (ascaridole).

Bicyclic monoterpenes possess two condensed non-aromatic rings. Depending on the hydrocarbon Structure, they are subdivided into the following types: thujane, carene, pinane, camphane, fenchane, etc.

Thujane-type compounds:

Thujane derivatives are found in plants of the genera Thuja, Tanacetum (tansy), and Juniperus.

Carene-type compounds:

Carene derivatives are characterized by a main cyclohexane ring and a three-membered side ring formed from the isopropylene group of menthane. Two isomeric forms exist: D3-carene and A4-carene. These compounds are present in birch raw Materials.

Pinane-type compounds:

Bicyclic monoterpenoids of the pinane type have been detected in juniper berries, tansy flowers, and pine needles.

Camphane-type compounds:

Camphane-type monoterpenoids are found in valerian rhizomes and roots, camphor laurel wood, as well as fir needles and oil.



Last update: 06/08/2026

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