Hillig ( 2005 ) and Clarke and Merlin ( 2013 ) accept a two (or three) species inter-
pretation; while Small ( 2015 ) claims one species system with different varieties
(Hillig 2005 ; Clarke and Merlin 2013 ; Small 2015 ). Initially,Cannabis sativawas
categorized in two distinct chemotype/phenotype varieties by Fetterman et al.
( 1971 ) namely, drug type andfiber types based on the presence of the most
abundant cannabinoids in its leaves and buds (Fetterman et al. 1971 ). Plants were
classified as‘drug phenotype’if THC/CBD ratio exceeded one, otherwise as‘fiber
phenotype’ distinguished C. sativa in three phenotypes namely drug type
(THC/CBD ratio >>1), intermediate type (THC/CBD ratio close to 1.0) andfiber
type (THC/CBD ratio <<1) (Small and Beckstead 1973 ).
Cannabis is considered as a chemically complex species based on its numerous
natural constituents. It contains a unique class of terpenophenolic compounds called
cannabinoids, which have been extensively studied since the discovery of the
chemical structure of tetrahydrocannabinol (D^9 -THC) commonly known as THC,
the main constituent responsible for the psychoactive effects. A total of 565 con-
stituents including 120 cannabinoids have been reported fromC. sativa, so far
(ElSohly et al.2016a, b). The pharmacological and therapeutic properties of
preparations ofC. sativaL. as well as THC have been extensively reviewed
(Grotenhermen and Müller-Vahl 2012 ). An additional important cannabinoid in
cannabis of current interest is cannabidiol (CBD). There has been a 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 ). Besides, D^9 -THC and CBD, other major
cannabinoids have been reported from cannabis include tetrahydrocannabivarin
(THCV), cannabichromene (CBC), cannabigerol (CBG) and cannabinol (CBN).
Numerous natural constituents representing many chemical classes have been
isolated and identified as a result of chemical investigation ofC. sativa. 423 com-
pounds were reported to be isolated and identified in 1980 by Turner et al. ( 1980 ).
This number was increased in 1995 to 483 compounds (Ross and ElSohly 1995 ).
Extra seven compounds were added to the list between 1995 and 2005 (ElSohly and
Slade 2005 ). The total number of isolated and identified compounds fromC. sativa
reached 565 in 2016 which was reviewed by ElSohly et al.2016a,b. These
compounds could be classified into cannabinoids and non-cannabinoids (alkaloids,
flavonoids, terpenoids, amino acids and others).
Cannabinoids are a group of C21 terpenophenolic compounds, related to the
terpenes with their ring structure derived from geranyl pyrophosphate, which rep-
resent the most specific group of compounds in this plant. Many synthetic
cannabinoids have been produced and widely spread, this prompted the use of the
term“Phytocannabinoids”as a description for the naturally isolated ones (Pate
1999 ). Chemically, cannabinoids could be divided into 11 subclasses (Table7.1),
the Δ^9 -tetrahydrocannabinol (D^9 -THC) type is the most important type of
cannabinoids that will be discussed in this chapter. Studying the chemistry of the
D^9 -THC type cannabinoids as well as the analysis of the plant material for quali-
tative and quantitative determination of the cannabinoids content is the main focus
of this chapter.
162 M.M. Radwan et al.