Table 2.

Classification of terpenes and terpenoids on the basis of their isoprene units.

Class	Isoprene Units	Carbon Atoms	Examples
Monoterpene	2	10	Canphor, eucalyptol, geraniol, lavandulol, limonene, menthol, pinene, thymol
Sesquiterpene	3	15	Abscisic acid, bergamotene, cedrol, curcumene, patchoulol, vetivone
Diterpene	4	20	Abietic acid, cafestol, caffeol, carnosol, gibberellin, phytol
Triterpene	6	30	Betulinic acid, morolic acid, oleanolic acid, ursolic acid, brassinosteroids, saponins
Tetraterpene	8	40	Carotenoids (e.g., α-carotene, β-carotene, crocin, licopene) and xanthophylls (e.g., lutein, zeaxanthin, α-cryptoxanthin, β-cryptoxanthin)
Polyterpene	>8	>40	Cytokinines, gutta-percha, rubber