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TABLE 1.5 Cannabinoids Identified in Marijuana

Cannabinoid

Common

No. of Known

Group

Abbreviation

Variants in Each Group

     

D9-Tetrahydrocannabinol

D9-THC

9

D8-Tetrahydrocannabinol

D8-THC

2

Cannabichromene

CBC

5

Cannabicyclol

CBL

3

Cannabidiol

CBD

7

Cannabielsoin

CBE

5

Cannabigerol

CBG

6

Cannabinidiol

CBND

2

Cannabinol

CBN

7

Cannabitriol

CBT

9

Miscellaneous types

 

11

Total

 

66

groups of closely related cannabinoids, many of which differ by only a single chemical moiety and might be midpoints along biochemical path—ways-that is, degradation products, precursors, or byproducts.16,18 D9 -tetrahydrocannabinol (D9-THC) is the primary psychoactive ingredient; depending on the particular plant, either THC or cannabidiol is the most abundant cannabinoid in marijuana (Figure 1.1). Throughout this report, THC is used to indicate D9-THC. In the few cases where variants of THC are discussed, the full names are used. All the cannabinoids are lipophilic—they are highly soluble in fatty fluids and tissues but not in water. Indeed, THC is so lipophilic that it is aptly described as ''greasy."

Throughout this report, marijuana refers to unpurified plant extracts, including leaves and flower tops, regardless of how they are consumed—whether by ingestion or by smoking. References to the effects of marijuana should be understood to include the composite effects of its various components; that is, the effects of THC are included among the effects of marijuana, but not all the effects of marijuana are necessarily due to THC. Discussions concerning cannabinoids refer only to those particular compounds and not to the plant extract. This distinction is important; it is often blurred or exaggerated.

Cannabinoids are produced in epidermal glands on the leaves (especially the upper ones), stems, and the bracts that support the flowers of the marijuana plant. Although the flower itself has no epidermal glands, it has the highest cannabinoid content anywhere on the plant, probably because of the accumulation of resin secreted by the supporting bracteole



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