OH
O
H
Geraniol
An acyclic monoterpene
(+)-α-Pinene
A cyclic monoterpene
(−)-Menthol
A monoterpene alcohol
CHO
O
H
(+)-α-Phellandrene
A monoterpene hydrocarbon
(+)-Citronellal
A monoterpene aldehyde
(+)-Camphor
A monoterpene ketone
COOH
OH
(+)-trans-Chrysanthemic acid
A monoterpene acid
Carvacrol
A phenolic sesquiterpene
Botanical sources
A number of plants produce a variety of monoterpenes. The following
table lists just a few of these sources, and their major monoterpene
components.
Source
Major monoterpenes
Common name
Botanical name (Family)
Black pepper
Piper nigrum (Piperaceae)
a- and b-pinene, phellandrene
Peppermint leaf
Mentha piperita (Lamiaceae)
Menthol, menthone
Oil of rose
Rosa centifolia (Rosaceae)
Geraniol, citronellol, linalool
Cardamom
Elettaria cardamomum
a-terpineol, a-terpinene
(Zingiberaceae)
Rosemary
Rosmarinus officinalis
Borneol, cineole, camphene
(Lamiaceae)
Bitter orange
Citrus aurantium (Rutaceae)
(þ)-limonene, geranial
Camphor
Cinnamomum camphora
(þ)-camphor
(Lauraceae)
Caraway
Carum carvi (Apiaceae)
(þ)-carvone, (þ)-limonene
Thyme
Thymus vulgaris (Lamiaceae)
Thymol, carvacrol
6.5.4 Sesquiterpenes
Sesquiterpenes, 15-carbon-containing terpenoids, are composed of three
isoprene units, and found abundantly in plants, e.g. artemisinin from
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CH6 NATURAL PRODUCT CHEMISTRY