It is a very small botanical family that includes two genera:
HUMULUS (hops) and CANNABIS (hemp).
There is some confusion about the existence or not of several cannabis species, which are sometimes described as mere subspecies or varieties of Cannabis sativa.
Some botanists distinguish several "types" of hemp:
- Cannabis sativa cultivated hemp, main species,
- Cannabis sativa - indica, "Indian" hemp,
- Cannabis sativaruuderalis, wild hemp (Europe)
- Cannabis sativa- afghanica, Afghan hemp
In recent years, cannabis cultivation has become legally possible in some European and North American countries. "Cannabis growers" have improved crop varieties in order to obtain better yields and a higher percentage of active substances, in particular by making cross-breeding, the cultivated species are now almost all hybrids.
Cannabis sativa (the type species) is a plant that provides:
- a plant fiber used on a large scale for a very long time to make the strongest rope, sails for the navy, canvases or nets, the frame of carpets etc ...
- a seed, rich in oil (32%) and protein (22%), used in bird breeding and incidentally by anglers,
- pharmacologically active substances (cannabinoids) contained in the leaves, flowers, resin. in variable quantity and quality.
Cannabis sativa (probably native to Asia) is cultivated or harvested for a very long time in Asia and Europe.
The Chinese have known and used hemp for more than 4000 years.
The people of West Asia, Assyrians, Scythians and Arabs appreciated the intoxicating power of the vapors of hemp resin (burned as incense).
It was during the Islamic expansion that other peoples around the Mediterranean adopted it as a medicinal or intoxicating plant.
Its introduction in Europe dates back to France to the Napoleonic expedition to Egypt and follows the colonization of India by England.
Some European artists have a time adopted cannabis, the famous club of haschishins 1840-1860 (Baudelaire and his friends), but in the 19th century it main interest was its medical use.
In the new world, it was first introduced in Mexico (marijuana) and then in the southern US by European populations.
Cannabis sativa is an annual plant, more or less bushy and up to 5 m high (usually 1 to 2m).
The leaves have a different arrangement and shape depending on the level on the plant, near the base they are opposite and cut into 5 to 10 segments, near the ends they are alternate (spiral) and slightly cut (1 to 3 segments) .
Male plants die after anthesis, while females live 1 to 2 months after pollination.
The male flowers are grouped in axial or terminal panicles, the female flowers are in compacted cymes mixed with leafy bracts.
CHEMICAL COMPOSITION AND PROPERTIES
Many active components have been described and isolated from hemp ( essential oil, alkaloids, flavonoids, sugars, fatty acids ..) but the most important are the CANNABINOIDS present in the leaves, bracts and especially the exuded resin, but they are absent from seeds and stems.
Among these cannabinoids (they are between 60 and 90 according to the specialists), the most important is the delta 9 tetrahydrocannabinol (THC).
It is a lipophilic substance that can be absorbed digestive or respiratory and metabolized by the liver, gives many pharmacologically active and inactive hydroxylated derivatives.
It appears that some of these derivatives are more active than THC, which explains in part the faster and more pronounced effects of cannabis among "regular users" with an hepatic metabolism ready to use THC.
THC and its derivatives are found in the urine after absorption, its elimination is slow.
THC and its derivatives persist in the blood, and thus urine, one to several weeks after cannabis use.
THC (which mainly binds to the endocannabinoid CB1 receptors) and its metabolized derivatives in the body interfere with the NEURO-TRANSMITTERS: serotonin, acetylcholine, gamma aminobutyric acid, noradrenaline and cause significant but varied effects on the psyche, perception sensory and neuro-vegetative system according to the dose ingested and the personality of the subject.
- feeling of well being with light intoxication, relaxation and a strong tendency to laugh,
- or on the contrary slight anxiety and anxiety,
- modification of sensory perception (sounds, colors, distance, shapes),
-modification of the temporal perception (the time is elastic),
- disruption of motor coordination (pay attention to driving),
- alteration more or less controlable of memory with sometimes confusing ideas, sometimes brilliant, often out of the subject in short,
-induction of sleep, for some it may be the only effect,
- improvement or modification of sexual feelings,
- at high doses, anxiety and anxiety are frequent, hallucinations are more marked and lasting, even after the disappearance of THC from the blood.
It is considered that the toxicity of THC is low, the toxicologists do not report fatal intoxication, on the other hand, the overdose can provoke the appearance of acute psychos.
Epidemiologists warn against the use of cannabis in children and young adolescents because there is a risk of higher than normal percentage of severe psychosis in their adulthood.
THC dependence is low, physical dependence also, discontinuation of the drug causes a withdrawal syndrome without need of major medication.
Cannabis and its derivatives are nonetheless banned from trade and consumption in many countries; the cultivation of hemp is very regulated.
But the LEGISLATION CONCERNING CANNABIS CHANGE QUICKLY since the end of the 2000s.
THC has other pharmacological properties:
- it is a bronchodilator (asthma),
- it reduces the intraocular pressure (glaucoma),
- it is analgesic (neuropathic pain, advanced cancer),
- it alleviates disorders related to chemotherapy: vomiting, nausea, loss of appetite,
- its effects on cancers and their metastasis is studied but controversial
- it may interact with hormonal metabolism and possibly modify the immune defense, this remains controversial.
Two other cannabinoids are of interest to the scientific community and cannabis users: CANNABIDIOL or CBD and CANNABINOL or CBN.
CBD has less psychotropic effect but interacts with many receptors in the body.
These global pharmacological effects are not yet well defined, let us quote in a few:
- It acts on the pain, it is an analgesic (in particular the neuropathic pains of the multiple sclerosis),
- on the excitability of the central nervous system, it is an anticonvulsant (convulsions, epilepsy),
- it could delay the dissemination of certain cancer cells (metastasis),
- it modifies the action of THC by delaying its elimination and modulating the anxiety or anxiety related to it,
- evaluations are in progress to know its effect on serious psychosis (schisophrenia).
CBN is a product of the oxidation of THC that forms during the drying of cannabis if it is too prolonged, in the sun and in the open air.
It does not exist in the fresh plant but can dominate the effects of THC in badly dried marijuana.
It is sedative of the central nervous system (tendency to sleep, dizziness) sometimes psychic depression, loss of motivation, indifference, memory disorders in those who consume a lot of cannabis from South America or Central America.
Despite the global ban on its use (but the laws of the countries evolve rather quickly, and the "recreational and medical" use becomes possible in many countries: example Canada and many American states), cannabis sativa is consumed a little all over the world for the sweet drunkenness and sensory changes it induces in the form of:
- cigarettes of leaves pure or mixed with tobacco,
- resin with or without plant debris, smoked or ingested,
- very concentrated forms: essence or extracts.
The purely medicinal use is old (China, India, Europe), it was used as analgesic, anticonvulsant and soporific: menstrual pain, pain of childbirth, migraine, epilepsy, preparation to operations (China), combat readiness (Arabs), meditation aid (India). It was known as an anti-asthmatic, calming cough.
It was also useful as an adjunct treatment in opioid withdrawal.
Cannabis sativa has long been part of the British Pharmacopoeia.
Currently, one recognizes its ANTI-ASTMATIC power by bronchodilatation and many THC derivatives have been tested for their ANTI-CONVULSIVANT, SPASMOLYTIC or ANALGESIC PROPERTIES (soothing pains), but there are often significant side effects on the psyche that limit its use.
Similarly, it has been shown that it has an ANTI-EMETIC effect , especially in cancer CHEMOTHERAPY patients (observations in regular smokers of marijuana); derivatives have been tested for this indication and appear promising.
Recently the "SATIVEX" has been approved in several Western countries (including Spain). In France sativex has been authorized and banned, nothing is clear about it at the legal level.
This drug (based on cannabidiol with little THC) seems interesting to calm, among others, the stubborn NEUROPATHIC PAINS of MULTIPLE SCLEROSIS.
It is a mouth spray, penetration of the product being at the level of the lining of the mouth, the patient himself dosing the number and distribution of spraying in the day according to its painful episodes.
Users of this cannabis extract note the absence or moderation of "psychic" effects.
Other drugs based on cannabinoids exist and are marketed in some European or North American countries: examples MARINOL = dronabinol (synthetic THC), BEDROCAN, BEDIOL, BEDROBINOL, legislation in France remains very restrictive against them.
ANTALGIC, ANTIASTHMATIC , ANTISPASMODIC AND GENERALLY FORBIDDEN
Hemp is widespread around the world. Some varieties secrete a resin that contains very active substances on the nervous system. Their absorption by digestive or respiratory causes according to the dose: a slight drunkenness, a disorientation in time, changes in the perception of noises and colors, incoordination of movements, anxiety, or even a real psychosis. This resin also contains antispasmodic and antiasthmatic compounds. Resin hemp is banned from cultivation and consumption in most countries of the world, but the legislation is changing and MEDICAL USE of cannabis is more and more accepted in many countries especially to calm some rebellious pains.
Copyright 2019: Dr Jean-Michel Hurtel