The flowers and leaves of some 'industrial' hemp strains may be a viable source of CBD, but hemp is by no means an optimal source. Hemp typically contains far less CBD than CBD-rich cannabis. Huge amounts of industrial hemp are required to extract small amounts of CBD, raising the risk of toxic contaminants (hemp is a 'bio-accumulator'; drawing heavy metals from the soil). Single-molecule CBD synthesised in a lab or extracted and refined from industrial hemp lacks critical medicinal terpenes and secondary cannabinoids found in cannabis strains. These compounds interact with CBD and THC to enhance their therapeutic benefits.
CBD indirectly stimulates endogenous cannabinoid signalling by suppressing the enzyme 'fatty acid amide hydroxylase' (FAAH). This enzyme breaks down anandamide, a naturally occurring endogenous cannabinoid neurotransmitter, or 'endogenous ligand' which binds CB1 receptors which are concentrated in the brain and central nervous system. Because FAAH is responsible for breaking down anandamide, less FAAH means more anandamide (and greater CB1 activation) in the body for longer. By inhibiting the enzyme that metabolises and destroys anandamide, CBD enhances the body’s innate protective endocannabinoid response. At the same time, CBD powerfully opposes the action of THC at the CB1 receptor, thereby muting the psychoactive effects of THC. CBD also stimulates the release of 2-AG, another endocannabinoid that activates both CB1 and CB2 receptors. CB2 receptors are predominant in the peripheral nervous and immune systems.
♋ Anti-proliferative - inhibits the growth of tumours / cancer cells. A study published in 2007 showed that CBD inhibited a particular gene, Id-1, which is responsible for the growth of cancer cells in the body. By inhibiting this gene CBD shuts down the growth of cancer cells, potentially stopping or even reversing tumour growth. Researchers at the California Pacific Medical Center have shown that CBD reduces brain cancer and breast cancer cell proliferation and metastasis by inhibiting the expression of the Id-1 gene. GPR55, a G protein-coupled receptor that some researchers postulate may actually be a third cannabinoid receptor type (CB-3?), when activated, promotes cancer cell proliferation, according to a 2010 study by researchers at the Chinese Academy of Sciences. CBD is a GPR55 antagonist, as University of Aberdeen discovered, also in 2010. By blocking GPR55 signalling, CBD might act to decrease both bone re-absorption and cancer cell proliferation. This is one of many molecular pathways through which CBD exerts an anti-cancer effect. Best results were obtained when CBD was administered in combination with THC. ID-1 expression is implicated in several kinds of aggressive cancer.
♋ Anti-psioratic – CBD is the only cannabinoid identified to treat psoriasis.
♋ Anti-psychotic – tranquilising effects relieve symptoms of psychosis; two terpenoids, Linalool and Myrcene, also help. CBD is a powerful anti-psychotic currently being considered for use in treating schizophrenia and other psychoses. CBD appears to have a very similar chemical profile to certain atypical anti-psychotic drugs. PPAR-alpha agonists in particular are indicated as an adjunct treatment for schizophrenia. Polymorphisms or mutations in the gene encoding PPAR-alpha are associated with schizophrenia. Furthermore, PPAR-alpha activation is both anti-inflammatory and can decrease dopamine release, thereby minimising schizophrenic symptoms. This may help to explain how and why CBD has anti-psychotic effects.
♋ Anxiolytic (anti-anxiety) / Anti-depressant – CBD is the only cannabinoid identified that relieves anxiety, but two terpenoids also help (Linalool and Limonene). CBD may exert its anti-anxiety effect by activating adenosine receptors. Adenosine receptors play significant roles in cardiovascular function, regulating myocardial oxygen consumption and coronary blood flow. The adenosine (A2A) receptor has broad anti-inflammatory effects throughout the body. Adenosine receptors also play a significant role in the brain as they down-regulate release of other neurotransmitters (dopamine and glutamate). CBD also stimulates the 5-HT1a (hydroxytryptamine) receptor in the brain involved in the re-uptake of serotonin and other processes that aid depression and anxiety. The anti-depressant properties of CBD are very similar to the trycyclic anti-depressant Imipramine (also being evaluated for panic disorder). At the University of San Paulo in Brazil and King’s College in London, pioneering research into CBD and the neural correlates of anxiety have been studied. At high concentrations, CBD directly activates the 5-HT1A serotonin receptor, thereby conferring an anti-depressant effect. This receptor is implicated in a range of biological and neurological processes, including, but not necessarily limited to, anxiety, addiction, appetite, sleep, pain perception, nausea and vomiting. 5-HT receptors are activated by the neurotransmitter serotonin, found in both the central and peripheral nervous systems. 5-HT receptors trigger various intracellular cascades of chemical messages to produce either an excitatory or inhibitory response, depending on the chemical context of the message. CBD triggers an inhibitory response that slows down 5-HT1A signalling. In comparison, LSD, mescaline, magic mushrooms and several other hallucinogenic drugs activate a different type of 5-HT receptor that produces an excitatory response.