The Analytical Chemistry of Cannabis

Quality Assessment, Assurance, and Regulation of Medicinal Marijuana and Cannabinoid Preparations

Brian F. Thomas, Mahmoud A. ElSohly, Mahmoud Elsohly

• Publisher: Elsevier
• Year: 2015
• Print ISBN: 9780128046463
• eBook ISBN: 9780128046708
• Topic: Physical Sciences
• Subtopic: Biochemistry

A volume in the Emerging Issues in Analytical Chemistry series, The Analytical Chemistry of Cannabis: Quality Assessment, Assurance, and Regulation of Medicinal Marijuana and Cannabinoid Preparations provides analytical chemistry methods that address the latest issues surrounding cannabis-based products. The plethora of marketed strains of cannabis and cannabinoid-containing products, combined with the lack of industry standards and labelling requirements, adds to the general perception of poor quality control and limited product oversight. The methods described in this leading-edge volume help to support the manufacturing, labelling, and distribution of safe and consistent products with known chemical content and demonstrated performance characteristics. It treats analytical chemistry within the context of the diverse issues surrounding medicinal and recreational cannabis in a manner designed to foster understanding and rational perspective in non-scientist stakeholders as well as scientists who are concerned with bringing a necessary degree of order to a field now characterized by confusion and contradiction. - Addresses current and emerging analytical chemistry methods - an approach that is unique among the literature on this topic - Presents information from a broad perspective of the issues in a single compact volume - Employs language comprehensible to non-technical stakeholders as well as to specialists in analytical chemistry

Chapter 1

The Botany of Cannabis sativa L.

Abstract

Cannabis sativa L. is among the oldest known cultivated plants, with a long history of medical use. Cannabis produces a unique class of terpenophenolic compounds called cannabinoids, 104 of which have been isolated, the major biologically active one being Δ⁹-tetrahydrocannabinol. Cannabidiol, an antiepileptic, is also important. Cannabis is an annual, normally dioecious and occasionally monoecious, wind-pollinated species and is highly allogamous (cross-fertilization) in nature. Therefore, maintaining the efficacy of selected high Δ⁹-tetrahydrocannabinol-yielding elite varieties grown from seeds under field or greenhouse conditions is very difficult. Thus, a careful screening of elite mother clones using GC-FID and their propagation using vegetative cuttings or advanced biotechnological approaches, including micropropagation, is the most suitable way to maintain quality. This chapter describes the botany, species debate, phenotype, screening of high-yielding clones using GC-FID, indoor and outdoor cultivation, micropropagation, quality assurance of propagated plants, harvesting, processing, and storage.

Keywords

Cannabis sativa L.; cannabidiol; Δ⁹-tetrahydrocannabinol; indoor growing; micropropagation; outdoor growing

Cannabis sativa L. is a widespread species in nature. It is found in various habitats ranging from sea level to the temperate and alpine foothills of the Himalayas, from where it was probably spread over the last 10,000 years.^1,2 The age-old cultivation makes its original distribution difficult to pinpoint.³ Cannabis has a long history of medicinal use in the Middle East and Asia, with references as far back as the 6th century BCE, and it was introduced in Western Europe as a medicine in the early 19th century to treat epilepsy, tetanus, rheumatism, migraine, asthma, trigeminal neuralgia, fatigue, and insomnia.^4,5

As a plant, it is valued for its hallucinogenic and medicinal properties, more recently being used for pain, glaucoma, nausea, asthma, depression, insomnia, and neuralgia.^6,7 Derivatives are used in HIV/AIDS⁸ and multiple sclerosis.⁹ The pharmacology and therapeutic efficacy of cannabis preparations and its main active constituent Δ⁹-tetrahydrocannabinol (Δ⁹-THC) have been extensively reviewed.^10–12 The other important cannabinoid constituent 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.^13,14 Other than Δ⁹-THC and CBD, tetrahydrocannabivarin (THCV), cannabinol (CBN), cannabigerol (CBG), and cannabichromene (CBC) are major isolates. Fig. 1.1 shows chemical structures.

Figure 1.1 Chemical structures of major cannabinoids present in Cannabis sativa. Δ⁹-THC, Δ⁹-tetrahydrocannabinol; THCV, tetrahydrocannabivarin; CBN, cannabinol; CBG, cannabigerol; CBC, cannabichromene; CBD, cannabidiol.

Cannabis is also one of the oldest sources of food and textile fiber.^15–17 Hemp grown for fiber was introduced in Western Asia and Egypt and subsequently in Europe between 1000 and 2000 BCE. Cultivation of hemp in Europe became widespread after 500 CE. The crop was first brought to South America (Chile) in 1545, and to North America (Port Royal, Acadia) in 1606.¹⁸ Now its cultivation is prohibited or highly regulated in the United States.

Botanical Description

Table 1.1 describes the botanical nomenclature of C. sativa L. Cannabis is a highly variable species in terms of botany, genetics, and chemical constituents. The number of species in the Cannabis genus has long been controversial. Some reports proposed Cannabis as a polytypic genus.^19–22 However, based on morphological, anatomical, phytochemical, and genetic studies, it is generally treated as having a single, highly polymorphic species, C. sativa L.^23–26 Other reported species are Cannabis indica Lam. and Cannabis ruderalis Janisch, but plants considered to have belonged to these species are now recognized as varieties of C. sativa L. (var. indica and var. ruderalis, respectively). Cannabis sativa and indica are widely cultivated and economically important; Cannabis ruderalis is hardier and grows in the northern Himalayas and the southern states of the former Soviet Union but is rarely cultivated for drug content.

Table 1.1

Botanical Nomenclature of Cannabis sativa L.

Category	Botanical Nomenclature
Kingdom	Plantae—Plants
Subkingdom	Tracheobionta—Vascular plants
Superdivision	Spermatophyta—Seed plants
Division	Magnoliophyta—Flowering plants
Class	Magnoliopsida—Dicotyledons
Subclass	Hamamelididae
Order	Urticales
Family	Cannabaceae
Genus	Cannabis
Species	Cannabis sativa L.

The main morphological difference between indica and sativa is in their leaves. The leaves of sativa are much smaller and thinner, whereas those of indica have wide fingers and are deep green, often tinged with purple; at maturity, they turn dark purple. Indica plants are shorter and bushier, usually under 6 ft tall and rarely over 8 ft Indica has short branches laden with thick, dense buds, which mature early, usually at the beginning of September in the Northern Hemisphere. Indica buds also vary in color from dark green to purple, with cooler conditions inducing more intense coloration. Indica flowers earlier. The natural distribution of indica is Afghanistan, Pakistan, India, and surrounding areas. The plants of sativa have long branches, with the lower ones spreading 4 ft or more from the central stalk, as on a conical Christmas tree. Height varies from 6 ft to more than 20 ft, with 8–12 ft being the most common. Buds are long and thin and far less densely populated than in indica, but longer, sometimes 3 ft or more. Maturation time varies considerably depending on the variety and environmental conditions. Low Δ⁹-THC Midwestern sativa varieties (ditchweed) mature in August and September, while equatorial varieties mature from October to December. Buds of sativa require intense light to thicken and swell; indica does not. Sativa tends to be higher in Δ⁹-THC and lower in CBD than indica. Sativa is found all over the world and comprises most of the drug type equatorial varieties such as Colombian, Mexican, Nigerian, and South African, where marijuana plants can be very potent. Cannabis has many local common names, some of which are given in Table 1.2.

Table 1.2

Common Cannabis Names in Different Languages

Language	Common Names
Arabic	Bhang, hashish qinnib, hasheesh kenneb, qinnib, tîl
Chinese	Xian ma, ye ma
Danish	Hemp
Dutch	Hennep
English	Hemp, marihuana
Finnish	Hamppu
French	Chanvre, chanvre d’Inde, chanvre indien, chanvrier
German	Hanf, haschisch, indischer hanf
Hindi	Bhang, charas, ganja
Japanese	Mashinin
Nepalese	Charas, gajiimaa, gaanjaa
Portuguese	Cânhamo, maconha
Russian	Kannabis sativa
Spanish	Cáñamo, grifa, hachís, mariguana, marijuana
Swedish	Porkanchaa

Normally, cannabis exhibits a dioecious (male and female flowers develop on separate plants) and occasionally a monoecious (hermaphrodite) phenotype. It flowers in the shorter days (below 12-h photoperiod) and continues growing vegetatively in the longer photoperiod. Sex is determined by heteromorphic chromosomes (males being heterogametic XY, females homogametic XX). Male flowers can be differentiated from female by their different morphological appearance. At the vegetative stage, differentiation is difficult because of morphological similarities. Molecular techniques, however, can differentiate at an early stage...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• List of Contributors
• Foreword
• Preface
• Acknowledgments
• Chapter 1. The Botany of Cannabis sativa L.
• Chapter 2. Biosynthesis and Pharmacology of Phytocannabinoids and Related Chemical Constituents
• Chapter 3. Medical Cannabis Formulations
• Chapter 4. Analytical Methods in Formulation Development and Manufacturing
• Chapter 5. Quality Control and Stability Assessment
• Chapter 6. The Roles of Research and Regulation
• Chapter 7. The Future of Cannabinoid Therapeutics