Cannabidiol

Abstract: Δ9-Tetrahydrocannabinol (THC) is the main source of the pharmacological effects caused by the consumption of cannabis, both the marijuana-like action and the medicinal benefits of the plant. However, its acid metabolite THC-COOH, the non-psychotropic cannabidiol (CBD), several cannabinoid analogues and newly discovered modulators of the endogenous cannabinoid system are also promising candidates for clinical research and therapeutic uses. Cannabinoids exert many effects through activation of G-protein-coupled cannabinoid receptors in the brain and peripheral tissues. Additionally, there is evidence for nonreceptor-dependent mechanisms. Natural cannabis products and single cannabinoids are usually inhaled or taken orally; the rectal route, sublingual administration, transdermal delivery, eye drops and aerosols have only been used in a few studies and are of little relevance in practice today. The pharmacokinetics of THC vary as a function of its route of administration. Pulmonary assimilation of inhaled THC causes a maximum plasma concentration within minutes, psychotropic effects start within seconds to a few minutes, reach a maximum after 15–30 minutes, and taper off within 2–3 hours. Following oral ingestion, psychotropic effects set in with a delay of 30–90 minutes, reach their maximum after 2–3 hours and last for about 4–12 hours, depending on dose and specific effect. At doses exceeding the psychotropic threshold, ingestion of cannabis usually causes enhanced well-being and relaxation with an intensification of ordinary sensory experiences. The most important acute adverse effects caused by overdosing are anxiety and panic attacks, and with regard to somatic effects increased heart rate and changes in blood pressure. Regular use of cannabis may lead to dependency and to a mild withdrawal syndrome. The existence and the intensity of possible long-term adverse effects on psyche and cognition, immune system, fertility and pregnancy remain controversial. They are reported to be low in humans and do not preclude legitimate therapeutic use of cannabis-based drugs. Properties of cannabis that might be of therapeutic use include analgesia, muscle relaxation, immunosuppression, sedation, improvement of mood, stimulation of appetite, antiemesis, lowering of intraocular pressure, bronchodilation, neuroprotection and induction of apoptosis in cancer cells.

Abstract: BackgroundThe Dravet syndrome is a complex childhood epilepsy disorder that is associated with drug-resistant seizures and a high mortality rate We studied cannabidiol for the treatment of drug-resistant seizures in the Dravet syndrome MethodsIn this double-blind, placebo-controlled trial, we randomly assigned 120 children and young adults with the Dravet syndrome and drug-resistant seizures to receive either cannabidiol oral solution at a dose of 20 mg per kilogram of body weight per day or placebo, in addition to standard antiepileptic treatment The primary end point was the change in convulsive-seizure frequency over a 14-week treatment period, as compared with a 4-week baseline period ResultsThe median frequency of convulsive seizures per month decreased from 124 to 59 with cannabidiol, as compared with a decrease from 149 to 141 with placebo (adjusted median difference between the cannabidiol group and the placebo group in change in seizure frequency, −228 percentage points; 95% confidence i

Abstract: (−)-Cannabidiol (CBD) is a non-psychotropic component of Cannabis with possible therapeutic use as an anti-inflammatory drug. Little is known on the possible molecular targets of this compound. We investigated whether CBD and some of its derivatives interact with vanilloid receptor type 1 (VR1), the receptor for capsaicin, or with proteins that inactivate the endogenous cannabinoid, anandamide (AEA). CBD and its enantiomer, (+)-CBD, together with seven analogues, obtained by exchanging the C-7 methyl group of CBD with a hydroxy-methyl or a carboxyl function and/or the C-5′ pentyl group with a di-methyl-heptyl (DMH) group, were tested on: (a) VR1-mediated increase in cytosolic Ca2+ concentrations in cells over-expressing human VR1; (b) [14C]-AEA uptake by RBL-2H3 cells, which is facilitated by a selective membrane transporter; and (c) [14C]-AEA hydrolysis by rat brain membranes, which is catalysed by the fatty acid amide hydrolase. Both CBD and (+)-CBD, but not the other analogues, stimulated VR1 with EC50=3.2 – 3.5 μM, and with a maximal effect similar in efficacy to that of capsaicin, i.e. 67 – 70% of the effect obtained with ionomycin (4 μM). CBD (10 μM) desensitized VR1 to the action of capsaicin. The effects of maximal doses of the two compounds were not additive. (+)-5′-DMH-CBD and (+)-7-hydroxy-5′-DMH-CBD inhibited [14C]-AEA uptake (IC50=10.0 and 7.0 μM); the (−)-enantiomers were slightly less active (IC50=14.0 and 12.5 μM). CBD and (+)-CBD were also active (IC50=22.0 and 17.0 μM). CBD (IC50=27.5 μM), (+)-CBD (IC50=63.5 μM) and (−)-7-hydroxy-CBD (IC50=34 μM), but not the other analogues (IC50>100 μM), weakly inhibited [14C]-AEA hydrolysis. Only the (+)-isomers exhibited high affinity for CB1 and/or CB2 cannabinoid receptors. These findings suggest that VR1 receptors, or increased levels of endogenous AEA, might mediate some of the pharmacological effects of CBD and its analogues. In view of the facile high yield synthesis, and the weak affinity for CB1 and CB2 receptors, (−)-5′-DMH-CBD represents a valuable candidate for further investigation as inhibitor of AEA uptake and a possible new therapeutic agent. Keywords: Cannabinoid, endocannabinoid, vanilloid, receptors, FAAH, anandamide transporter Introduction Among the bioactive constituents of Cannabis sativa, (−)-cannabidiol (CBD, Figure 1) is one of those with the highest potential for therapeutic use (Mechoulam, 1999). Although the pharmacological properties of the other major Cannabis component, (−)-Δ9-tetrahydrocannabinol (THC), have been more thoroughly investigated (Mechoulam, 1999; Pertwee, 1999, for reviews), THC, unlike CBD, exhibits potent psychotropic effects, which have complicated the full assessment of its therapeutic potential. Little is known of the molecular mechanism(s) of action of CBD, which, unlike THC, has very little affinity for either cannabinoid receptor subtypes identified so far, the CB1 and CB2 receptors (Pertwee, 1997, for review). Recent studies, together with the earlier finding of the anti anxiety (Guimaraes et al., 1994), neuro-protective and anti-convulsive activity of CBD and some of its analogues (Consroe et al., 1981; Martin et al., 1987), indicate that CBD may also exert cyto-protective effects by inhibiting the release of inflammatory cytokines from blood cells (Srivastava et al., 1998; Malfait et al., 2000), thus producing an anti-inflammatory action, for example against rheumatoid arthritis (Malfait et al., 2000). These effects of CBD may be due to its anti-oxidant properties (Hampson et al., 1998), to its direct interaction with cytochrome p450-enzymes (Bornheim & Correia, 1989) and other enzymes of the ‘arachidonate cascade' (Burstein et al., 1985), or to an action at a specific receptor. Recent studies have investigated whether CBD interacts with proteins of the ‘endocannabinoid signalling system' other than the CB1/CB2 receptors. These proteins are: (i) fatty acid amide hydrolase (FAAH) (Cravatt et al., 1996), the intracellular enzyme catalysing the hydrolysis of the endogenous cannabinoid ligand, anandamide (arachidonoylethanolamide, AEA) (Ueda et al., 2000, for review); and (ii) the ‘anandamide membrane transporter' (AMT) (Di Marzo et al., 1994), which facilitates the transport of AEA across the cell membrane and, subsequently, its intracellular degradation (Hillard & Jarrahian, 2000, for review). It was found that CBD inhibits both AEA hydrolysis by FAAH-containing membrane preparations (Watanabe et al., 1996), and AEA uptake by RBL – 2H3 cells via the AMT (Rakhshan et al., 2000). Although these effects were observed at high μM concentrations, these findings raised the possibility that some of the pharmacological actions of CBD might be due to inhibition of AEA degradation, with subsequent enhancement of the endogenous levels of this mediator, for which neuroprotective (Hansen et al., 1998) and anti-inflammatory (Di Marzo et al., 2000a) properties have been previously suggested. Figure 1 Chemical structures of cannabidiol and capsaicin. The numbering for cannabidiol carbon atoms, and a possible cannabidiol-like conformation for capsaicin are shown. Many pharmacological activities of CBD have been established only in vivo, hence some of them may be due to CBD metabolites. The metabolism of CBD is well established. The primary step is hydroxylation on C-7, leading to (−)-7-hydroxy-CBD, followed by further oxidation to (−)-7-carboxy-CBD (Agurell et al., 1986). Although the metabolism of the dimethyl-heptyl homologue of CBD and of the (+) enantiomer of CBD has not been investigated, it is reasonable to assume that it follows the same pathways. Hence we prepared these CBD metabolites, their DMH homologues and some of the respective metabolites in the unnatural (+) series. In particular, in the present study we have examined whether the stereochemistry and the presence of certain chemical groups on the C-5′ and C-1 of CBD affect its capability of influencing AEA inactivation via the AMT and FAAH. Furthermore, we have addressed the question of the possible molecular transducer of CBD by studying the possibility that this natural compound, its (+)-enantiomer and some of its synthetic analogues, interact with another proposed target for AEA, i.e. the vanilloid receptor type 1 (VR1) for capsaicin (Holzer, 1991, Figure 1). This protein is a ligand-, heat- and proton-activated non-specific cation channel acting as a molecular integrator of nociceptive stimuli (Tominaga et al., 1998). Recently, it was discovered that AEA is a full, albeit weak, VR1 agonist (Zygmunt et al., 1999; Smart et al., 2000) and that synthetic capsaicin analogues can interact with either CB1 receptors or the AMT, or both (Di Marzo et al., 1998). Thus, there appears to be some overlap between the ligand recognition properties of VR1 and CB1 receptors and, in particular, of VR1 and the AMT (de petrocellis et al., 2000; Szallasi & Di Marzo, 2000). Although VR1, via the release of inflammatory and algesic peptides, is involved in inflammatory hyperalgesia (Davis et al., 2000; Caterina et al., 2000), the stimulation of this receptor by capsaicin and some of its analogues leads to rapid desensitization, with subsequent paradoxical analgesic and anti-inflammatory effects (Holzer, 1991; Szallasi & Blumberg, 1999). As a consequence of this tachyphylactic effect, capsaicin, like CBD, has been used to treat arthritis (Lorton et al., 2000) and convulsions (Dib & Falchi, 1996). We report data suggesting that VR1 is a possible molecular target for CBD, and that inhibitors of the AMT can be developed by chemical modification of this natural product.

Abstract: Cannabidiol is a component of marijuana that does not activate cannabinoid receptors, but moderately inhibits the degradation of the endocannabinoid anandamide. We previously reported that an elevation of anandamide levels in cerebrospinal fluid inversely correlated to psychotic symptoms. Furthermore, enhanced anandamide signaling let to a lower transition rate from initial prodromal states into frank psychosis as well as postponed transition. In our translational approach, we performed a double-blind, randomized clinical trial of cannabidiol vs amisulpride, a potent antipsychotic, in acute schizophrenia to evaluate the clinical relevance of our initial findings. Either treatment was safe and led to significant clinical improvement, but cannabidiol displayed a markedly superior sideeffect profile. Moreover, cannabidiol treatment was accompanied by a significant increase in serum anandamide levels, which was significantly associated with clinical improvement. The results suggest that inhibition of anandamide deactivation may contribute to the antipsychotic effects of cannabidiol potentially representing a completely new mechanism in the treatment of schizophrenia. Translational Psychiatry (2012) 2, e94; doi:10.1038/tp.2012.15; published online 20 March 2012