Tetrahydrocannabinol, chemical structure

Endocannabinoids. Figure 1 Chemical structures of the two most studied endocannabinoids, anandamide and 2-arachidonoylglycerol, of Cannabis sativa psychoactive principle, A9-tetrahydrocannabinol, and of the CB-i receptor antagonist/inverse agonist, rimonabant. 

FIGURE 18.2 Chemical structures of A9-tetrahydrocannabinol (A9-THC) derived from marijuana, and the endogenous cannabimimetic eicosanoid, anadamide (arachidonylethanolamide), identified in the human brain. 

Figure 19.1. Chemical structure of main active ingredient of Cannabis sativa, A9-tetrahydrocannabinol (THC) and the naturally occurring ligand for cannabinoid receptors anandamide (arachidonyl ethanolamide).

Several investigations have been carried out over the years to isolate THC from the plant material, mostly to determine its chemical structure or to investigate the phytochemistry of the plant. In 1942, Wollner, et al., (11) reported the isolation of tetrahydrocannabinol from cannabis extract red oil . Red oil was prepared by extraction of the plant material with ether, followed by distillation of the concentrated extract at room pressure followed by redistillation under reduced pressure (15-50 mm Hg). 

FIGURE 20.1 Chemical structures of exogenous (A -tetrahydrocannabinol, A -THC) and endogenous (anan-damide, AEA, and iV-stearoylethanolamine, SIiA) cannabinoids, and of some oxygenated derivatives of AIiA. 

Cannabis sativa is the genus and species name of a flowering plant which has been used medicinally for thousands of years. Delta-9-tetrahydrocannabi-nol (A -THC) is responsible for almost all the psychoactive effects of cannabis, but is only one of more than 60 similar compounds found in cannabis which, together, are collectively known as cannabi-noids. Cannabinoid agonists that share the basic chemical structure of delta-9-tetrahydrocannabinol have been increasingly studied in recent years for potential benefits in various types of pain and pain syndromes. 

The chemical structure of A -tetrahydrocannabinol, determined by Gaoni and Mechoulam in 1964, is illustrated in Figure 6.3. Unlike many other biologically active chemicals of plant origin, A -tetrahydrocannabinol is a highly hydrophobic molecule, a property that has hindered the progress on its mode of action for nearly three decades. Indeed, not only was A -tetrahydrocannabinol more difficult to handle experimentally than such hydrophylic alkaloids as cocaine or morphine, but also its preference for lipid... 

The psychoactive and medicinal chemical compounds found in the resin of the marijuana plant are known as cannabinoids. The cannabis plant contains more than 460 known compounds over 60 of these have a cannabinoid structure. The only cannabinoid that is highly psychoactive and present in large amounts in the resin of the cannabis plant is tetrahydrocannabinol, or THC. The other two major cannabinoids are the cannabidiols and the cannabinols. It appears that the cannabis plant first produces the mildly active cannabidiols, which are converted to the more psychoactive THCs and then broken down to relatively inactive... 

Flere are the structures of the three principal tetrahydrocannabinols and of the parent, which differ mainly in chemical bonding ... 

Figure 6-6a). Tetrahydrocannabinol (THC), the active constituent of marijuana, also has the molecular formula CjiHjqOj (Figure 6-6b). Progesterone and THC are isomers they have the same chemical formula but veiy different structures. Does this mean that they have similar effects on the human body No The different structures result in different effects-structure is everything. Nature can take exactly the same atoms in exactly the same numbers and make two different molecules with drastically different properties and functions. One of them, progesterone, makes pregnancy possible the other, THC, alters the way the brain processes stimuli. 

By definition, cannabinoids comprise a variety of distinct chemical classes which bind to the cannabinoid receptor. These include the classical cannabinoids structurally related to tetrahydrocannabinol, the non-classical cannabinoids, the aminoalkylindoles, the eicosanoids related to the endocannabinoids, 1,5-diarylpyrazoles, quinolines and atylsulphonamides and additional compounds that do not fall into these standard classes. According to their production and origin, there are three types of cannabinoids phytocannabinoids, endogenous cannabinoids, and synthetic cannabinoids. 

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