Cannabidiol (CBD) is a psychoactive cannabinoid found in Cannabis. It is a major constituent of the plant, representing up to 40% in its extracts.
CBD alone is not intoxicating but displayed sedative effects in animal tests. Some research, however, indicates that CBD can increase alertness. It may decrease the rate of THC clearance from the body, perhaps by interfering with the metabolism of THC in the liver. CBD appears to affect both the CB1 and CB2 receptors- with higher affinity for the CB2 receptors .Cannabis indica dominant strains of the plant are known to be higher in CBD than Cannabis sativa strains.
Medically, it appears to relieve convulsion, inflammation, anxiety, and nausea, and to inhibit cancer cell growth. Recent studies have shown cannabidiol to be as effective as atypical antipsychotics in treating schizophrenia.
In November 2007 it was reported that CBD reduces growth of aggressive human breast cancer cells in vitro and reduces their invasiveness. It thus represents the first non-toxic exogenous agent that can lead to down-regulation of tumor aggressiveness. It is also a neuroprotective antioxidant.
A 2008 study published in the British Journal of Psychiatry showed significant differences in Oxford-Liverpool Inventory of Feelings and Experiences scores between three groups: The first consisted of non-cannabis users, the second of users who tested positive for Δ9-THC only, and the third consisted of users who tested positive for both Δ9-THC and CBD. The Δ9-THC only subset scored significantly higher for unusual experiences, while users of both Δ9-THC and CBD had much lower introvertive anhedonia scores .
Contents |
Medicinal use
In April 2005, Canadian authorities approved the marketing of Sativex, a mouth spray for multiple sclerosis to alleviate pain. Sativex contains tetrahydrocannabinol together with cannabidiol. It is marketed in Canada by GW Pharmaceuticals.
Initial research is showing that CBD has an effect in reducing schizophrenic symptoms in patients. Further research has verified these results. Leweke et al., (2009) performed a double blind, 4 week, explorative study controlled clinical trial, to compare the effects of purified cannabidiol and the atypical antipsychotic amisulpride on improving the symptoms of schizophrenia in 42 patients with acute schizophrenia. ‘Both treatments were associated with a significant decrease of psychotic symptoms after 2 and 4 weeks as assessed by BPRS and PANSS. However, there was no statistical difference between both treatment groups. In contrast, cannabidiol induced significantly less side effects (EPS, increase in prolactin, weight gain) when compared to amisulpride’. The authors conclude cannabidiol revealed substantial antipsychotic properties in acute paranoid schizophirenia (Leweke et al., 2009). This led the authors to suggest the endocannabinoid system plays an adaptive role in the development of paranoid schizophirenia and that this research provides evidence that this mechanism may be a valuable target for ‘antipsychotic treament strategies’ .
Pharmacology
Cannabidiol has no affinity for CB1 and CB2 receptors but acts as an indirect antagonist of cannabinoid agonists. Recently it was found to be an antagonist at the putative new cannabinoid receptor, GPR55, a GPCR expressed in the caudate nucleus and putamen.
Cannabidiol has also been shown to inhibit cancer cell growth with low potency in non-cancer cells. Although the inhibitory mechanism is not yet fully understood, Ligresti et al. suggest that “cannabidiol exerts its effects on these cells through a combination of mechanisms that include either direct or indirect activation of CB2 and TRPV1 receptors, and induction of oxidative stress, all contributing to induce apoptosis.” In November 2007, researchers at the California Pacific Medical Center reported that CBD shows promise for controlling the spread of metastatic breast cancer. In vitro CBD downregulates the activity of the gene Id-1 which is responsible for tumor metastasis.
Chemistry
Cannabidiol is insoluble in water but soluble in organic solvents. At room temperature it is a colorless crystalline solid. In strongly basic medium and the presence of air it is oxidized to a quinone. Under acidic conditions it cyclizes to THC. The synthesis of cannabidiol has been accomplished by several research groups.
Legal Status
In Canada Cannabadiol is a Schedule 2 Drug, a category that encompasses quantities of cannabis less than 30 grams, and various related synthetic derivatives and preparations. In the United States it is a Schedule I Drug.
See also
- Cannabinoids
- Cannabinoid receptors
- Cannabis
- Health issues and the effects of cannabis
- Medical marijuana
References | External Links
Related Reading:
