A Fenchone Derivative Effectively Abrogates Joint Damage Following Post-Traumatic Osteoarthritis in Lewis Rats.

BACKGROUND: In a previous report, we have identified the cannabinoid receptor 2 (CB2) agonist HU308 to possess a beneficial effect in preventing age and trauma-induced osteoarthritis (OA) in mice. The effects of HU308 were largely related to the capacity of this compound to induce cartilage anabolism which was dependent on the CREB/SOX9 axis, and exhibited pro-survival and pro-proliferative hallmarks of articular cartilage following treatment. Here, we utilized the novel cannabinoid-fenchone CB2 agonists (1B, 1D), which were previously reported to render anti-inflammatory effects in a zymosan model. METHODS: Initially, we assessed the selectivity of CB2 using a Gs-protein receptor cAMP potency assay, which was also validated for antagonistic effects dependent on the Gi-protein receptor cAMP pathway. Based on EC50 values, 1D was selected for a zymosan inflammatory pain model. Next, 1D was administered in two doses intra-articularly (IA), in a post-traumatic medial meniscal tear (MMT, Lewis rats) model, and compared to sham, vehicle, and a positive control consisting of fibroblast growth factor 18 (FGF18) administration. The histopathological assessment was carried out according to the Osteoarthritis Research Society International (OARSI) guidelines for rat models following 28 days post-MMT. RESULTS: The G protein receptor assays confirmed that both 1B and 1D possess CB2 agonistic effects in cell lines and in chondrocytes. Co-administering a CB2 antagonists to 25 mg/kg 1D in a paw inflammatory pain model abolished 1D-related anti-swelling effect and partially abolishing its analgesic effects. Using an MMT model, the high dose (i.e., 24 µg) of 1D administered via IA route, exhibited reduced cartilage damage. Particularly, this dose of 1D exhibited a 30% improvement in cartilage degeneration (zonal/total tibial scores) and lesion depth ratios (44%), comparable to the FGF18 positive control. Synovitis scores remained unaffected and histopathologic evaluation of subchondral bone damage did not suggest that 1D treatment changed the load-bearing ability of the rats. Contrary to the anabolic effect of FGF18, synovial inflammation was observed and was accompanied by increased osteophyte size. CONCLUSION: The structural histopathological analysis supports a disease-modifying effect of IA-administered 1D compound without any deleterious effects on the joint structure.

Fenchone Derivatives as a Novel Class of CB2 Selective Ligands: Design, Synthesis, X-ray Structure and Therapeutic Potential.

A series of novel cannabinoid-type derivatives were synthesized by the coupling of (1S,4R)-(+) and (1R,4S)-(-)-fenchones with various resorcinols/phenols. The fenchone-resorcinol derivatives were fluorinated using Selectfluor and demethylated using sodium ethanethiolate in dimethylformamide (DMF). The absolute configurations of four compounds were determined by X-ray single crystal diffraction. The fenchone-resorcinol analogs possessed high affinity and selectivity for the CB2 cannabinoid receptor. One of the analogues synthesized, 2-(2',6'-dimethoxy-4'-(2″-methyloctan-2″-yl)phenyl)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol (1d), had a high affinity (Ki = 3.51 nM) and selectivity for the human CB2 receptor (hCB2). In the [35S]GTPγS binding assay, our lead compound was found to be a highly potent and efficacious hCB2 receptor agonist (EC50 = 2.59 nM, E(max) = 89.6%). Two of the fenchone derivatives were found to possess anti-inflammatory and analgesic properties. Molecular-modeling studies elucidated the binding interactions of 1d within the CB2 binding site.

Avidekel Cannabis extracts and cannabidiol are as efficient as Copaxone in suppressing EAE in SJL/J mice.

Multiple sclerosis (MS) is an autoimmune disease leading to the destruction of myelin with consequent axonal degeneration and severe physical debilitation. The disease can be treated with immunosuppressive drugs that alleviate the symptoms and retard disease aggravation. One such drug in clinical use is glatiramer acetate (Copaxone). The non-psychotropic immunosuppressive cannabinoid compound cannabidiol (CBD) has recently been shown to have beneficial effects on experimental autoimmune encephalomyelitis (EAE). The aim of our study was to compare the efficacy of CBD and standardized extracts from a CBD-rich, ∆9-THClowCannabis indica subspecies (Avidekel) with that of Copaxone. Our data show that CBD and purified Avidekel extracts are as efficient as Copaxone to alleviate the symptoms of proteolipid protein (PLP)-induced EAE in SJL/J mice. No synergistic effect was observed by combining CBD or Avidekel extracts with Copaxone. Our data support the use of Avidekel extracts in the treatment of MS symptoms.

The Anti-Inflammatory Properties of Terpenoids from Cannabis.

Introduction: Cannabinoids are well known to have anti-inflammatory effects in mammalians; however, the Cannabis plant also contains other compounds such as terpenoids, whose biological effects have not yet been characterized. The aim of this study was to compare the anti-inflammatory properties of terpenoids with those of cannabidiol (CBD). Materials and Methods: Essential oils prepared from three monoecious nonpsychoactive chemotypes of Cannabis were analyzed for their terpenoid content and subsequently studied pharmacologically for their anti-inflammatory properties in vitro and in vivo. Results: In vitro, the three essential oils rich in terpenoids partly inhibited reactive oxygen intermediate and nitric oxide radical (NO•) production in RAW 264.7 stimulated macrophages. The three terpenoid-rich oils exerted moderate anti-inflammatory activities in an in vivo anti-inflammatory model without affecting tumor necrosis factor alpha (TNFα) serum levels. Conclusions: The different Cannabis chemotypes showed distinct compositions of terpenoids. The terpenoid-rich essential oils exert anti-inflammatory and antinociceptive activities in vitro and in vivo, which vary according to their composition. Their effects seem to act independent of TNFα. None of the essential oils was as effective as purified CBD. In contrast to CBD that exerts prolonged immunosuppression and might be used in chronic inflammation, the terpenoids showed only a transient immunosuppression and might thus be used to relieve acute inflammation.