D^9 -Tetrahydrocannabinolic acid (D^9 -THCA), is the precursor of the primary psy-
choactive agent. This compound is produced as an acid in the glandular trichomes
of the inflorescence bracts and undergoes decarboxylation with age or heating to
D^9 -Tetrahydrocannabinol (D^9 -THC, Fig.3.4a) (Turner et al. 1980 ). An additional
important cannabinoid in Cannabis of current interest is Cannabidiol (CBD,
Fig.3.4b). There has been significant interest in CBD over the last few years
because of its reported activity as an antiepileptic agent, particularly its promise for
the treatment of intractable pediatric epilepsy (Devinsky et al. 2014 ). Researchers
have documented the pharmacologic and therapeutic potency ofCannabisprepa-
rations andD^9 -THC and CBD (Grinspoon and Bakalar 1993 ; Mattes et al. 1994 and
Brenneisen et al. 1996 , Zuardi 2006 ). The detailed pharmacology and therapeutic
potential of phytocannabinoids are described in Chap. 9. Besides,D^9 -THC and
CBD, other major cannabinoids of Cannabis include Tetrahydrocannabivarin
(THCV), Cannabichromene (CBC), Cannabigerol (CBG) and Cannabinol (CBN).
D^8 -THC is another closely related isomer ofD^9 -THC which is much less abundant
and less potent thanD^9 -THC (Small and Marcus 2003 ). A total of 565Cannabis
constituents and 120 phytocannabinoids have been isolated fromCannabis sativa
so far (ElSohly et al. 2017 ). More in-depth details about phytocannabinoids are
given in Chap. 7.
The biosynthesis of cannabinoids inCannabis sativa has been extensively
reviewed (Shoyama et al. 1975 ; Kajima and Piraux 1982 ; Fellermeier and Zenk
Fig. 3.3 Flowering male (a) and female (b) plants ofCannabis sativa
84 S. Chandra et al.