The name hemp is thought to originate from the biblical Hebrew term “qeneh bosem”, which can be translated as “aromatic cane”. The term was later adopted by Germanic peoples and resulted in words like “henep” and “hanf” that were later transformed to the English word hemp. Nowadays, the term hemp refers to plants of Cannabis Sativa L. that exhibit a cannabinoid profile different to that of plants referred to as cannabis. The distinction is based on the level of tetrahydrocannabinol (THC) found in the dry plant material. Legally speaking, the boundary between hemp and cannabis is at 0.3 weight percent of THC in the USA and 0.2 weight percent of THC in most European countries. Hemp plants are known to contain a higher amount of cannabidiol (CBD) with the CBD-to-THC ratio usually being around 30:1.
Cannabis sativa L. is an annual flowering plant, meaning that it completes its entire life cycle from seed germination to seed production and death within one growing season. Most plants are dioecious, meaning that female and male flowers appear on separate plants and the pollination most often occurs with the assistance of wind and, rarely, animals. In some cases, cannabis or hemp plants can grow as hermaphrodites, meaning that a single plant contains both female and male flowers. The general morphological features of Cannabis sativa L. plants are a long thin stem, big fingered fan leaves, and relatively thick flowers with so-called glandular trichomes growing on their surface. These glandular trichomes can be considered as “biofactories” where the specific chemicals, such as cannabinoids, are formed.
The first to attract the attention of humans were the seeds and the stem. The seeds were used as food because of their high nutritional value and the stems were used for different building and reinforcing purposes. The stem of Cannabis sativa L. consists of a woody inner part surrounded by the outer epidermis that contains fiber cells. Throughout the years cultivars that were grown exclusively for stems have been developed, most of which nowadays fall into the category of hemp, meaning the plants with a lower amount of THC and a higher amount of CBD.
The known uses of hemp, for what we today call “industrial purposes”, date back to 8000 BCE, when the Chinese used hemp fibers for clothing. The first ropes based on hemp fibers were made in 5000–4000 BCE and the first paper based on hemp was discovered in a tomb from roughly 2500 BCE.
Throughout history, hemp has contributed to many branches of industry:
• Food industry: Hemp seeds are rich in essential fatty acids and protein, also containing considerable amounts of vitamin E, phosphorus, potassium, sodium, magnesium, iron and zinc. Particularly popular is cold-pressed hemp-seed oil that many people regularly use in their daily diet.
• Textile industry: Fibers obtained from hemp stalks have a long tradition of use in the textile industry. In the past, famous designer names such as Ralph Laurent and Calvin Klein have used hemp fibers in their clothing. Also, major companies like Adidas used hemp fibers for parts of their sports shoes. Recently, the use of hemp fibers has been returning to the textile industry.
• Construction: The material obtained from hemp stalk is a rich source of tough raw material for different construction purposes. An example is the use of hemp-lime-based materials that can be used for the construction of a house. The basic building material is marketed under the name hempcrete, which is a biocomposite of hemp shives (the woody, inner portion of the hemp stalk), lime and sand. Furthermore, insulation can be based on hemp wool produced using hemp fibers from the outer epidermis of the hemp stalk.
Industrial hemp can easily become an important part of a future sustainable economy. The inner and outer parts of the stem are used for construction materials, the seeds are for dietary purposes, the flowers and leaves are utilized as sources of cannabinoids, such as CBD, which have been shown to exhibit anti-inflammatory properties, reduce anxiety, help with pain relief and sleep-deprivation disorders. Even the juices from hemp roots have therapeutic values, such as the relief of stiffness in joints and gout, according to ancient Chinese pharmacopeia.