Phytocannabinoids

“Phytocannabinoids, also called ”natural cannabinoids”, ”herbal cannabinoids”, and ”classical cannabinoids”, are only known to occur naturally in significant quantity in the cannabis plant, and are concentrated in a viscous resin that is produced in glandular structures known as trichomes.

In addition to cannabinoids, the resin is rich in terpenes, which are largely responsible for the odour of the cannabis plant.

Phytocannabinoids are nearly insoluble in water but are soluble in lipids, alcohols, and other non-polar organic solvents. However, as phenols, they form more water-soluble phenolate salts under strongly alkaline conditions.

All-natural cannabinoids are derived from their respective 2-carboxylic acids (2-COOH) by decarboxylation (catalyzed by heat, light, or alkaline conditions).

Types

At least 66 cannabinoids have been isolated from the cannabis plant. To the right the main classes of natural cannabinoids are shown. All classes derive from cannabigerol-type compounds and differ mainly in the way this precursor is cyclized.

Tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) are the most prevalent natural cannabinoids and have received the most study. Other common cannabinoids are listed below:

  • CBG Cannabigerol
  • CBC Cannabichromene
  • CBL Cannabicyclol
  • CBV Cannabivarin
  • THCV Tetrahydrocannabivarin
  • CBDV Cannabidivarin
  • CBCV Cannabichromevarin
  • CBGV Cannabigerovarin
  • CBGM Cannabigerol Monoethyl Ether

Tetrahydrocannabinol

Tetrahydrocannabinol (THC) is the primary psychoactive component of the plant. It appears to ease moderate pain (analgetic) and to be neuroprotective. THC has approximately equal affinity for the CB1 and CB2 receptors. Its effects are perceived to be more cerebral.

”Delta”-9-Tetrahydrocannabinol (Δ9-THC, THC) and ”delta”-8-tetrahydrocannabinol (Δ8-THC), mimic the action of anandamide, a neurotransmitter produced naturally in the body. The THCs produce the ”high” associated with cannabis by binding to the CB1 cannabinoid receptors in the brain.

Cannabidiol

Cannabidiol (CBD) is not psychoactive, and was thought not to affect the psychoactivity of THC. However, recent evidence shows that smokers of cannabis with a higher CBD/THC ratio were less likely to experience schizophrenia-like symptoms.

This is supported by psychological tests, in which participants experience less intense psychotic effects when intravenous THC was co-administered with CBD (as measured with a PANSS test).

It has been hypothesized that CBD acts as an allosteric antagonist at the CB1 receptor and thus alters the psychoactive effects of THC.

It appears to relieve convulsion, inflammation, anxiety, and nausea. CBD has a greater affinity for the CB2 receptor than for the CB1 receptor.

Cannabigerol

Cannabigerol (CBG) is non-psychotomimetic but still affects the overall effects of Cannabis. It acts as an α2-adrenergic receptor agonist, 5-HT1A receptor antagonist, and CB1 receptor antagonist. It also binds to the CB2 receptor.

Tetrahydrocannabivarin

Tetrahydrocannabivarin (THCV) is prevalent in certain South African and Southeast Asian strains of Cannabis. It is an antagonist of THC at CB1 receptors and attenuates the psychoactive effects of THC.

Cannabichromene

Cannabichromene (CBC) is non-psychoactive and does not affect the psychoactivity of THC It is found in nearly all tissues in a wide range of animals.

Two analogs of anandamide, 7,10,13,16-docosatetraenoylethanolamide and ”homo”-γ-linolenoylethanolamine, have similar pharmacology.

All of these are members of a family of signalling lipids called ”N”-acylethanolamides, which also includes the noncannabimimetic palmitoylethanolamide and oleoylethanolamine, which possess anti-inflammatory and orexigenic effects, respectively. Many ”N”-acylethanolamines have also been identified in plant seeds and in molluscs.

  • 2-arachidonoyl glycerol (2-AG)

Another endocannabinoid, 2-arachidonoyl glycerol, binds to both the CB1 and CB2 receptors with similar affinity, acting as a full agonist at both, and there is some controversy over whether 2-AG rather than anandamide is chiefly responsible for endocannabinoid signalling ”in vivo”.

In particular, one ”in vitro” study suggests that 2-AG is capable of stimulating higher G-protein activation than anandamide, although the physiological implications of this finding are not yet known.

  • 2-arachidonyl glyceryl ether (noladin ether)

In 2001, a third, ether-type endocannabinoid, 2-arachidonyl glyceryl ether (noladin ether), was isolated from porcine brain.

Prior to this discovery, it had been synthesized as a stable analog of 2-AG; indeed, some controversy remains over its classification as an endocannabinoid, as another group failed to detect the substance at “any appreciable amount” in the brains of several different mammalian species.

It binds to the CB1 cannabinoid receptor (”K”i = 21.2 nmol/L) and causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. It binds primarily to the CB1 receptor, and only weakly to the CB2 receptor.

Like anandamide, NADA is also an agonist for the vanilloid receptor subtype 1 (TRPV1), a member of the vanilloid receptor family.

  • Virodhamine (OAE)

A fifth endocannabinoid, virodhamine, or ”O”-arachidonoyl-ethanolamine (OAE), was discovered in June 2002. Although it is a full agonist at CB2 and a partial agonist at CB1, it behaves as a CB1 antagonist ”in vivo”.

In rats, virodhamine was found to be present at comparable or slightly lower concentrations than anandamide in the brain, but 2- to 9-fold higher concentrations peripherally.

Function

Endocannabinoids serve as intercellular ‘lipid messengers’, signaling molecules that are released from one cell and activate the cannabinoid receptors present on other nearby cells.

Although in this intercellular signaling role they are similar to the well-known monoamine neurotransmitters, such as acetylcholine and dopamine, endocannabinoids differ in numerous ways from them. For instance, they use retrograde signaling.

Furthermore, endocannabinoids are lipophilic molecules that are not very soluble in water. They are not stored in vesicles, and exist as integral constituents of the membrane bilayers that make up cells. They are believed to be synthesized ‘on-demand’ rather than made and stored for later use.

The mechanisms and enzymes underlying the biosynthesis of endocannabinoids remain elusive and continue to be an area of active research.

The endocannabinoid 2-AG has been found in bovine and human maternal milk.

Retrograde signal

Conventional neurotransmitters are released from a ‘presynaptic’ cell and activate appropriate receptors on a ‘postsynaptic’ cell, where presynaptic and postsynaptic designate the sending and receiving sides of a synapse, respectively.

Endocannabinoids, on the other hand, are described as retrograde transmitters because they most commonly travel ‘backwards’ against the usual synaptic transmitter flow.

They are, in effect, released from the postsynaptic cell and act on the presynaptic cell, where the target receptors are densely concentrated on axonal terminals in the zones from which conventional neurotransmitters are released.

Activation of cannabinoid receptors temporarily reduces the amount of conventional neurotransmitter released.

This endocannabinoid mediated system permits the postsynaptic cell to control its own incoming synaptic traffic.

The ultimate effect on the endocannabinoid-releasing cell depends on the nature of the conventional transmitter being controlled.

For instance, when the release of the inhibitory transmitter GABA is reduced, the net effect is an increase in the excitability of the endocannabinoid-releasing cell.

On the converse, when release of the excitatory neurotransmitter glutamate is reduced, the net effect is a decrease in the excitability of the endocannabinoid-releasing cell.

Range

Endocannabinoids are hydrophobic molecules. They cannot travel unaided for long distances in the aqueous medium surrounding the cells from which they are released, and therefore act locally on nearby target cells. Hence, although emanating diffusely from their source cells, they have much more restricted spheres of influence than do hormones, which can affect cells throughout the body.

Other thoughts

Endocannabinoids constitute a versatile system for affecting neuronal network properties in the nervous system.

”Scientific American” published an article in December 2004, entitled “The Brain’s Own Marijuana” discussing the endogenous cannabinoid system.

The current understanding recognizes the role that endocannabinoids play in almost every major life function in the human body.

U.S. Patent # 6630507

In 2003 The U.S.A.’s Government as represented by the Department of Health and Human Services was awarded a patent on cannabinoids as antioxidants and neuroprotectants. U.S. Patent 6630507.”

http://www.news-medical.net/health/Phytocannabinoids.aspx

Antidepressant-like effect of Δ9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L

“The antidepressant action of cannabis as well as the interaction between antidepressants and the endocannabinoid system has been reported. This study was conducted to assess the antidepressant-like activity of Δ9-THC and other cannabinoids… Results of this study show that Δ9-THC and other cannabinoids exert antidepressant-like actions, and thus may contribute to the overall mood-elevating properties of cannabis.”

“Cannabis sativa L. is one of the most widely used plants for both recreational and medicinal purposes. To date a total of 525 natural constituents covering several chemical classes have been isolated and identified from C. sativa. The cannabinoids belong to the chemical class of terpenophenolics, of which 85 have been uniquely identified in cannabis, including the most psychoactive cannabinoid, Δ9-tetrahydrocannabinol (Δ9-THC). The most common natural plant cannabinoids (phytocannabinoids) are: Δ9-THC, cannabidiol (CBD), cannabigerol (CBG), cannabichromene (CBC), and cannabinol (CBN). Several of the identified cannabinoids are both chemically and pharmacologically poorly characterized due to insufficient isolated amounts; however, the pharmacology of Δ9-THC has been widely studied, and it is regarded as the main psychoactive constituent of cannabis.”

“The psychological and physiological effects of cannabis have been extensively characterized, including euphoria, analgesia, sedation, memory and cognitive impairment, appetite stimulation, and anti-emesis. Most of these effects have been primarily attributed to Δ9-THC. Major advances in the field of cannabinoid research were achieved following the unraveling of the molecular mechanism underlying the actions of Δ9-THC and the discovery of the endocannabinoid system. The endocannabinoid system is regarded as a neuromodulator, and is comprised of cannabinoid receptors (primarily CB1 and CB2 receptors), their endogenous ligands, and enzymes responsible for the synthesis and metabolism of these ligands.”

“In addition to the established effects of cannabis, it is well recognized that mood elevation is one of the components of the complex experience elicited by cannabis. Much of our knowledge regarding cannabis effect on mood and anxiety is based on individual reports following cannabis use for medicinal or recreational purposes. Several anecdotal reports describe the antidepressant effect of cannabis, with patients confirming beneficial outcomes from its use in primary or secondary depressive disorders…”

“In conclusion, our results show that phytocannabinoids, including Δ9-THC, CBD, and CBC, exert antidepressant-like actions in animal models of behavioral despair. The exact mechanism underlying such activity is still unclear and confounded by the fact that these compounds have varying binding profiles to the established cannabinoid CB1 as well as to non CB1 receptors. The results support the effect of phytocannabinoids on mood disorders and provide potential leads for further studies.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866040/

Inhibitory effect of cannabichromene, a major non-psychotropic cannabinoid extracted from Cannabis sativa, on inflammation-induced hypermotility in mice.

“BACKGROUND AND PURPOSE:

Cannabichromene (CBC) is a major non-psychotropic phytocannabinoid that inhibits endocannabinoid inactivation and activates the transient receptor potential ankyrin-1 (TRPA1). Both endocannabinoids and TRPA1 may modulate gastrointestinal motility. Here, we investigated the effect of CBC on mouse intestinal motility in physiological and pathological states.”

“CONCLUSION AND IMPLICATIONS:

CBC selectively reduces inflammation-induced hypermotility in vivo in a manner that is not dependent on cannabinoid receptors or TRPA1.”

http://www.ncbi.nlm.nih.gov/pubmed/22300105

Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects

“The roots of cannabis synergy.”

“Tetrahydrocannabinol (THC) has been the primary focus of cannabis research since 1964, when Raphael Mechoulam isolated and synthesized it. More recently, the synergistic contributions of cannabidiol to cannabis pharmacology and analgesia have been scientifically demonstrated. Other phytocannabinoids, including tetrahydrocannabivarin, cannabigerol and cannabichromene, exert additional effects of therapeutic interest. Innovative conventional plant breeding has yielded cannabis chemotypes expressing high titres of each component for future study. This review will explore another echelon of phytotherapeutic agents, the cannabis terpenoids: limonene, myrcene, α-pinene, linalool, β-caryophyllene, caryophyllene oxide, nerolidol and phytol. Terpenoids share a precursor with phytocannabinoids, and are all flavour and fragrance components common to human diets that have been designated Generally Recognized as Safe by the US Food and Drug Administration and other regulatory agencies. Terpenoids are quite potent, and affect animal and even human behaviour when inhaled from ambient air at serum levels in the single digits ng·mL−1. They display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts. Particular focus will be placed on phytocannabinoid-terpenoid interactions that could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus). Scientific evidence is presented for non-cannabinoid plant components as putative antidotes to intoxicating effects of THC that could increase its therapeutic index. Methods for investigating entourage effects in future experiments will be proposed. Phytocannabinoid-terpenoid synergy, if proven, increases the likelihood that an extensive pipeline of new therapeutic products is possible from this venerable plant.”

“Cannabis has been a medicinal plant of unparalleled versatility for millennia, but whose mechanisms of action were an unsolved mystery until the discovery of tetrahydrocannabinol (THC), the first cannabinoid receptor, CB1, and the endocannabinoids, anandamide (arachidonoylethanolamide, AEA) and 2-arachidonoylglycerol (2-AG). While a host of phytocannabinoids were discovered in the 1960s: cannabidiol (CBD), cannabigerol (CBG), cannabichromene (CBC) (Gaoni and Mechoulam, cannabidivarin (CBDV) and tetrahydrocannabivarin (THCV), the overwhelming preponderance of research focused on psychoactive THC. Only recently has renewed interest been manifest in THC analogues, while other key components of the activity of cannabis and its extracts, the cannabis terpenoids, remain understudied. The current review will reconsider essential oil (EO) agents, their peculiar pharmacology and possible therapeutic interactions with phytocannabinoids.”

“Should positive outcomes result from such studies, phytopharmaceutical development may follow. The development of zero-cannabinoid cannabis chemotypes has provided extracts that will facilitate discernment of the pharmacological effects and contributions of different fractions. Breeding work has already resulted in chemotypes that produce 97% of monoterpenoid content as myrcene, or 77% as limonene (E. de Meijer, pers. comm.). Selective cross-breeding of high-terpenoid- and high-phytocannabinoid-specific chemotypes has thus become a rational target that may lead to novel approaches to such disorders as treatment-resistant depression, anxiety, drug dependency, dementia and a panoply of dermatological disorders, as well as industrial applications as safer pesticides and antiseptics. A better future via cannabis phytochemistry may be an achievable goal through further research of the entourage effect in this versatile plant that may help it fulfil its promise as a pharmacological treasure trove.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165946/