Hemp

Botanical Profile

Hemp (Cannabis sativa L.) is an annual herbaceous plant of the Cannabaceae with an exceptionally long history as a fibre, seed, oil and cultivated plant. Modern botanical and raw-material assessment must clearly distinguish plant part, cultivar, chemotype and intended use.

The species probably originated in Asia and has been spread by cultivation across large parts of the world. It is fast growing, with palmate leaves divided into narrow serrated leaflets. Plants may be dioecious or monoecious depending on genotype and breeding system.

Female inflorescences are rich in glandular trichomes in which many characteristic secondary metabolites are formed. Seeds, stems, leaves and inflorescences differ fundamentally in composition and technological use. Fibre hemp is selected for long bast fibres and stem yield; seed hemp for seed production; other cultivars for specific cannabinoid profiles.

Botanical identification is complicated by the long domestication history and strong morphological plasticity of the species. Modern taxonomic treatments generally recognise Cannabis sativa as a highly variable species, while historical literature has used additional species or subspecies concepts.

For raw-material quality and regulatory assessment, the exact plant part, authorised cultivar, THC content, harvest stage, processing method, contamination status and legal classification are decisive. Hemp is therefore a plant in which botanical, phytochemical and regulatory descriptions must be kept particularly precise.

Phytochemistry

The phytochemistry of Cannabis sativa varies strongly by plant part and chemotype. Characteristic constituents of glandular aerial tissues are cannabinoids and terpenes, while seeds are dominated by fatty oil, proteins and dietary fibre.

Important cannabinoids include cannabigerolic acid (CBGA), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA) and their neutral forms THC, CBD and CBG, together with numerous minor cannabinoids. In the fresh plant many cannabinoids occur predominantly as carboxylic acids; heat, storage and processing can cause decarboxylation. Relative concentrations determine chemotypic classifications, including fibre and industrial-hemp cultivars with very low THC content.

The terpene profile includes monoterpenes and sesquiterpenes such as myrcene, limonene, alpha-pinene, beta-caryophyllene, humulene and linalool. These volatile constituents contribute to cultivar-specific aroma and are also of chemotaxonomic interest. Flavonoids, including cannflavins, phenolic acids and other secondary metabolites have also been described.

Hemp seeds have a distinctly different composition. Their oil contains linoleic acid, alpha-linolenic acid, oleic acid and other fatty acids; seeds also provide proteins, fibre, tocopherols, phytosterols and mineral fractions. Hemp-seed oil must therefore be clearly distinguished from flower extracts. The interior of the seed naturally contains no relevant cannabinoid levels; contamination can occur through contact with cannabinoid-containing plant material.

Modern analysis employs HPLC, GC-MS, LC-MS and validated residue and cannabinoid methods. Identity, cultivar authorisation, THC limits, plant part, extraction process, pesticides, heavy metals, microbiological quality and contamination control are central to quality and legal compliance. Hemp is a prime example of a botanical raw material in which phytochemistry, quality assessment and regulation are inseparable.

Traditional Uses

Hemp has an exceptionally long history of use. Archaeobotanical and cultural-historical evidence shows that Cannabis sativa has been cultivated for millennia for fibre, oil and seed. In Asia, Europe and later worldwide, hemp fibres were valued for ropes, nets, textiles, sailcloth, paper and technical materials. Before synthetic fibres, hemp was one of the most important fibre crops.

Hemp seeds and hemp oil were also used for food and technical purposes in various regions. Seeds served as food or feed, while the oil was used in foods, lamps, paints, varnishes and soaps. These uses belong to European and Asian agricultural history and should be distinguished from modern cannabinoid-related discussions.

Traditional uses of flowers, resin or other plant parts also existed in different cultural regions. Historical contexts differed substantially between India, Central Asia, the Middle East, Europe and elsewhere; terminology, preparations and social evaluation varied accordingly. A factual profile should preserve this diversity without deriving inappropriate application claims.

In Europe, hemp was for centuries an everyday crop. Hemp fields, retting, fibre processing and rope making were part of rural and craft economies. During the twentieth century, regulatory developments, competition from cotton and synthetic fibres, and changing drug policies contributed to a major decline in cultivation.

Today hemp is again receiving attention as a fibre, seed, oil and industrial crop. Its traditional significance lies above all in the versatility of the plant: fibre, food, oil, technical raw materials and a complex cultural history.

Current Research

Modern research on Cannabis sativa is exceptionally broad. Major fields include genetics, breeding, chemotypes and regulatory control of constituents. Contemporary breeding differentiates fibre hemp, seed hemp, CBD-rich cultivars, medicinal cultivars and other specialised types. Genomic research is clarifying domestication history and the genetic basis of cannabinoid biosynthesis.

Phytochemical research investigates cannabinoids, terpenes, flavonoids and lipid fractions. HPLC is commonly used to determine acidic and neutral cannabinoids, while GC-MS is important for terpene analysis and selected residue questions. Biosynthesis of THCA, CBDA and CBGA is intensively studied, as are the effects of genetics, light, nutrition, stress and harvest time on chemical profiles.

Agronomic research examines fibre yield, seed quality, drought stress, crop ecology, pest pressure and sustainability. Industrial hemp is of interest for fibres, building materials, biocomposites and crop rotations, while regulatory requirements concerning THC levels and cultivar authorisation remain essential.

Food and raw-material research addresses hemp seed, hemp protein, hemp oil, press cake and fibre by-products, focusing on fatty-acid profiles, protein quality, oxidative stability and processing. For flower and extract raw materials, contamination control, decarboxylation, extraction technology and legal classification are additional key topics.

Sources

• Plants of the World Online. Kew Science. Royal Botanic Gardens, Kew.
• European Pharmacopoeia and relevant monographs on Cannabis raw materials.
• PubMed-indexed scientific literature on Cannabis sativa, cannabinoids and terpenes.
• Scientific literature on hemp domestication and agricultural history.
• Scientific literature on hemp seed, hemp oil, fibre hemp and industrial hemp.
• EU and national regulatory frameworks concerning industrial hemp, THC limits and cannabinoid-containing raw materials.