Overcoming the Bell‐Shaped Dose‐Response of Cannabidiol by Using Cannabis Extract Enriched in Cannabidiol

Ruth Gallily, Zhannah Yekhtin, Lumír Ondřej Hanuš

Pharmacology & Pharmacy, 2015, 6, 75-85

http://dx.doi.org/10.4236/pp.2015.62010

Abstract :
Cannabidiol (CBD), a major constituent of Cannabis, has been shown to be a powerful anti inflammatory and anti‐anxiety drug, without exerting a psychotropic effect. However, when given either intraperitoneally or orally as a purified product, a bell‐shaped dose‐response was observed, which limits its clinical use. In the present study, we have studied in mice the anti‐inflammatory and anti nociceptive activities of standardized plant extracts derived from the Cannabis sativa L., clone 202, which is highly enriched in CBD and hardly contains any psychoactive ingredients. In stark contrast to purified CBD, the clone 202 extract, when given either intraperitoneally or orally, provided a clear correlation between the anti‐inflammatory and anti‐nociceptive responses and the dose, with increasing responses upon increasing doses, which makes this plant medicine ideal for clinical uses. The clone 202 extract reduced zymosan‐induced paw swelling and pain in mice, and prevented TNFα production in vivo. It is likely that other components in the extract synergize with CBD to achieve the desired anti‐inflammatory action that may contribute to overcoming the bell‐shaped dose‐response of purified CBD. We therefore propose that Cannabis clone 202 (Avidekel) extract is superior over CBD for the treatment of inflammatory conditions.

Keywords : Cannabis sativa L. Clone 202, Cannabidiol, Anti‐Inflammation, Anti‐Nociceptive, TNFα

1. Introduction
Inflammation and pain have accompanied human life for ages. Many anti-inflammation and anti-pain medications and various approaches have been employed through the centuries and in recent time. Many of used drugs, however, impose severe side effects. Cannabis from various origins and species has been employed in various forms as anti-pain agents for thousands of years [1]-[3]. One example is the legitimated drug Sativex® (Nabiximols) that is used in the treatment of severe spasticity in patients with multiple sclerosis [4]. Two other drugs, Marinol (Dronabinol) and Cesamet, have been approved for use in cancer-related anorexia-cachexia syndrome as well as for nausea and vomiting [3]. But a major disadvantage of Cannabis phytomedicine is its psychoactive effects due to the presence of 9-Tetrahydrocannabinol (THC). Recently, a science-based approach is being conducted to specify the benefits of Cannabis and its many constituents. A Cannabis plant contains hundreds of different chemicals with about 60 – 80 chemicals known as cannabinoids [5]. The major Cannabis psychoactive molecule is the -tetrahydrocannabinol, known as THC, which binds with high affinity (Ki = 3 – 5 nM) [6] to both the cannabinoid CB1 receptor expressed in the brain and the CB2 receptor expressed on cells of the immune system [7]. Another major constituent is Cannabidiol (CBD) which is devoid of psychotropic effects and binds only with very low affinity (Ki > 10 μM) [6] to the CB1/CB2 receptors. The other cannabinoids are present in minute amounts. Stimulation of CB1 receptor is responsible for the Cannabis psychoactivity, while activation of the CB2 receptor leads to attenuated inflammation, decreased injury and accelerated regeneration in many disease states [7]. CBD has been shown to activate central nervous system’s limbic and paralimbic regions, which can reduce autonomic arousal and feeling of anxiety [3]. This is in contrast to THC which can be anxiogenic [3]. CBD has also been shown to have anti-emetic, anti-inflammatory and anti-psychotic effects [3]. Studies are looking for potential benefits of phytocannabinoids in management of neuropathic pain, hypertension, post-stroke neuroprotection, multiple sclerosis, epilepsy and cancer [3]. Doses up to 1500 mg per day as well as chronic use of CBD have been reported as being well tolerated by humans [3]. During the last 10 – 15 years, many studies have focused on the anti-inflammatory effects of purified CBD in various animal models, including rheumatoid arthritis, diabetes type 1, inflammatory bowel disease and multiple sclerosis [8]-[13]. These studies showed that purified CBD gives a bell-shaped dose-response curve. Healing was only observed when CBD was given within a very limited dose range, whereas no beneficial effect was achieved at either lower or higher doses. This trait of purified CBD imposes serious obstacles in planning human and animal studies. The aim of the present study was to find a CBD source that could eliminate the bell-shaped dose-response of purified CBD. We found that by using standardized plant extracts from the Cannabis clone 202 obtained from Tikun Olam, Israel, which is highly enriched in CBD and barely contains THC, a correlative antiinflammatory and anti-pain dose-response could be achieved when applied either intraperitoneally or orally in an inflammatory mouse model.

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pp-6-75-2015