Prospects for cannabinoids as anti-inflammatory agents

Cannabinoids and triple-negative breast cancer treatment

Triple-negative breast cancer (TNBC) accounts for about 10-20% of all breast cancer cases and is associated with an unfavorable prognosis. Until recently, treatment options for TNBC were limited to chemotherapy. A new successful systemic treatment is immunotherapy with immune checkpoint inhibitors, but new tumor-specific biomarkers are needed to improve patient outcomes. Cannabinoids show antitumor activity in most preclinical studies in TNBC models and do not appear to have adverse effects on chemotherapy. Clinical data are needed to evaluate efficacy and safety in humans. Importantly, the endocannabinoid system is linked to the immune system and immunosuppression. Therefore, cannabinoid receptors could be a potential biomarker for immune checkpoint inhibitor therapy or a novel mechanism to reverse resistance to immunotherapy. In this article, we provide an overview of the currently available information on how cannabinoids may influence standard therapy in TNBC.

Phytocannabinoids: Exploring Pharmacological Profiles and Their Impact on Therapeutical Use

Phytocannabinoids, a diverse group of naturally occurring compounds extracted from the Cannabis plant, have attracted interest due to their potential pharmacological effects and medicinal uses. This comprehensive review presents the intricate pharmacological profiles of phytocannabinoids while exploring the diverse impacts these substances have on biological systems. From the more than one hundred cannabinoids which were identified in the Cannabis plant so far, cannabidiol (CBD) and tetrahydrocannabinol (THC) are two of the most extensively studied phytocannabinoids. CBD is a non-psychoactive compound, which exhibits potential anti-inflammatory, neuroprotective, and anxiolytic properties, making it a promising candidate for a wide array of medical conditions. THC, known for its psychoactive effects, possesses analgesic and antiemetic properties, contributing to its therapeutic potential. In addition to THC and CBD, a wide range of additional phytocannabinoids have shown intriguing pharmacological effects, including cannabichromene (CBC), cannabigerol (CBG), and cannabinol (CBN). The endocannabinoid system, made up of the enzymes involved in the production and breakdown of endocannabinoids, cannabinoid receptors (CB1 and CB2), and endogenous ligands (endocannabinoids), is essential for preserving homeostasis in several physiological processes. Beyond their effects on the endocannabinoid system, phytocannabinoids are studied for their ability to modify ion channels, neurotransmitter receptors, and anti-oxidative pathways. The complex interaction between phytocannabinoids and biological systems offers hope for novel treatment approaches and lays the groundwork for further developments in the field of cannabinoid-based medicine. This review summarizes the state of the field, points out information gaps, and emphasizes the need for more studies to fully realize the therapeutic potential of phytocannabinoids.

Effects of cannabidiol on anandamide levels in individuals with cannabis use disorder: findings from a randomised clinical trial for the treatment of cannabis use disorder

Cannabidiol (CBD) has shown promise in treating psychiatric disorders, including cannabis use disorder - a major public health burden with no approved pharmacotherapies. However, the mechanisms through which CBD acts are poorly understood. One potential mechanism of CBD is increasing levels of anandamide, which has been implicated in psychiatric disorders including depression and cannabis use disorder. However, there is a lack of placebo-controlled human trials investigating this in psychiatric disorders. We therefore assessed whether CBD affects plasma anandamide levels compared to placebo, within a randomised clinical trial of CBD for the treatment of cannabis use disorder. Individuals meeting criteria for cannabis use disorder and attempting cannabis cessation were randomised to 28-day administration with placebo (n = 23), 400 mg CBD/day (n = 24) or 800 mg CBD/day (n = 23). We estimated the effects of each CBD dose compared to placebo on anandamide levels from baseline to day 28. Analyses were conducted both unadjusted and adjusted for cannabis use during the trial to account for effects of cannabis on the endocannabinoid system. We also investigated whether changes in plasma anandamide levels were associated with clinical outcomes relevant for cannabis use disorder (cannabis use, withdrawal, anxiety, depression). There was an effect of 800 mg CBD compared to placebo on anandamide levels from baseline to day 28 after adjusting for cannabis use. Pairwise comparisons indicated that anandamide levels unexpectedly reduced from baseline to day 28 in the placebo group (-0.048, 95% CI [-0.089, -0.007]), but did not change in the 800 mg CBD group (0.005, 95% CI [-0.036, 0.047]). There was no evidence for an effect of 400 mg CBD compared to placebo. Changes in anandamide levels were not associated with clinical outcomes. In conclusion, this study found preliminary evidence that 28-day treatment with CBD modulates anandamide levels in individuals with cannabis use disorder at doses of 800 mg/day but not 400 mg/day compared to placebo.

Cannabis smoking and age-related macular degeneration in the UK Biobank cohort

BACKGROUND

A major cause of blindness in older persons is age-related macular degeneration (AMD). Cigarette smoking is one of the major risk factors for AMD. In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to AMD.

METHODS

Our UK Biobank application was approved as UKB project 57245 (S.L., P.H.R.). Our analysis included all subjects with AMD and cannabis smoking information. The diagnosis of AMD was ascertained based on the 10th Revision of the International Classification of Diseases (ICD10), H35.3. Age at time of diagnosis of AMD was obtained from data field 5923. Cannabis information was recorded in UKB category 143, data field 20453, ever taken cannabis. A touch screen posed the question, "Have you taken CANNABIS (cannabis, grass, hash, ganja, blow, draw, skunk, weed, spliff, dope), even if it was a long time ago?" Possible answers were no, yes, 1-2 times, yes 3-10 times, yes, 11-100 times, yes, more than 100 times.

RESULTS

Subjects who had used marijuana more than 100 times had a significantly reduced risk of AMD, compared to subjects who had never used marijuana, and use of marijuana every day was associated with less AMD than use of marijuana less than once a month. But subjects who used cannabis 100 times or more were significantly younger (8years) when they developed AMD than subjects who never used cannabis.

CONCLUSION

Drusen, deposits of lipids, proteins, and cellular debris, accumulate in Bruch's membrane, limiting transport between the retinal pigment epithelium and the vasculature, triggering an inflammatory reaction. Marijuana can retard the inflammatory process because it is a powerful anti-inflammatory agent. Therefore, marijuana could reduce the risk of AMD. At the same time, blood vessels in the choriocapillaris below Bruch's membrane become more sparse with age. This phenomenon is believed to be a starting point for AMD. Marijuana can accelerate the loss of blood vessels due to its anti-angiogenic properties. Therefore, marijuana use might cause AMD to develop sooner in younger people.

The Current and Potential Application of Medicinal Cannabis Products in Dentistry

Oral and dental diseases are a major global burden, the most common non-communicable diseases (NCDs), and may even affect an individual's general quality of life and health. The most prevalent dental and oral health conditions are tooth decay (otherwise referred to as dental caries/cavities), oral cancers, gingivitis, periodontitis, periodontal (gum) disease, Noma, oro-dental trauma, oral manifestations of HIV, sensitive teeth, cracked teeth, broken teeth, and congenital anomalies such as cleft lip and palate. Herbs have been utilized for hundreds of years in traditional Chinese, African and Indian medicine and even in some Western countries, for the treatment of oral and dental conditions including but not limited to dental caries, gingivitis and toothaches, dental pulpitis, halitosis (bad breath), mucositis, sore throat, oral wound infections, and periodontal abscesses. Herbs have also been used as plaque removers (chew sticks), antimicrobials, analgesics, anti-inflammatory agents, and antiseptics. Cannabis sativa L. in particular has been utilized in traditional Asian medicine for tooth-pain management, prevention of dental caries and reduction in gum inflammation. The distribution of cannabinoid (CB) receptors in the mouth suggest that the endocannabinoid system may be a target for the treatment of oral and dental diseases. Most recently, interest has been geared toward the use of Cannabidiol (CBD), one of several secondary metabolites produced by C. sativa L. CBD is a known anti-inflammatory, analgesic, anxiolytic, anti-microbial and anti-cancer agent, and as a result, may have therapeutic potential against conditions such burning mouth syndrome, dental anxiety, gingivitis, and possible oral cancer. Other major secondary metabolites of C. sativa L. such as terpenes and flavonoids also share anti-inflammatory, analgesic, anxiolytic and anti-microbial properties and may also have dental and oral applications. This review will investigate the potential of secondary metabolites of C. sativa L. in the treatment of dental and oral diseases.

The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems. In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development. The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development. The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases. This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as "C. sativa L." or "medical cannabis"), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.

Can Cannabidiol Affect the Efficacy of Chemotherapy and Epigenetic Treatments in Cancer?

The success of cannabinoids with chronic neuropathic pain and anxiety has been demonstrated in a multitude of studies. With the high availability of a non-intoxicating compound, cannabidiol (CBD), an over-the-counter medication, has generated heightened interest in its use in the field of oncology. This review focuses on the widespread therapeutic potential of CBD with regard to enhanced wound healing, lowered toxicity profiles of chemotherapeutics, and augmented antitumorigenic effects. The current literature is sparse with regard to determining the clinically relevant concentrations of CBD given the biphasic nature of the compound’s response. Therefore, there is an imminent need for further dose-finding studies in order to determine the optimal dose of CBD for both intermittent and regular users. We address the potential influence of regular or occasional CBD usage on therapeutic outcomes in ovarian cancer patients. Additionally, as the development of chemoresistance in ovarian cancer results in treatment failure, the potential for CBD to augment the efficacy of conventional chemotherapeutic and epigenetic drugs is a topic of significant importance. Our review is focused on the widespread therapeutic potential of CBD and whether or not a synergistic role exists in combination with epigenetic and classic chemotherapy medications.

Effects of topical treatment of cannabidiol extract in a unique manuka factor 5 manuka honey carrier on second intention wound healing on equine distal limb wounds: a preliminary study

OBJECTIVE

Evaluate the effect of topical 1% cannabidiol on second intention wound healing in distal limb wounds of horses.

DESIGN

Experimental.

ANIMALS

Six Standardbred horses.

METHODS

A total of five 2.5 cm × 2.5 cm full thickness skin wounds were created on the dorsomedial aspect of the metacarpi of 6 horses. Wounds were contaminated with faeces on the day of wound creation. Each wound was then assigned to a treatment group; compounded 1% cannabidiol in unique manuka factor (UMF) 5 manuka honey, UMF 5 manuka honey, UMF 20 manuka honey or saline. Each treatment was applied topically daily for a total of 42 days. Legs were bandaged and bandages were changed, daily, for 13 days postoperatively. Digital photographs of each wound were taken on day 1 then weekly for 6 weeks. Wound size, daily healing rate and total time to healing were recorded and compared statistically.

RESULTS

Irrespective of the treatment, wounds did not retract as expected in the first 7 days after wound creation. There was no difference in wound area, daily healing rate, days to complete healing between treatment groups.

CONCLUSIONS

This preliminary study failed to demonstrate any difference in wound healing variables between treatment groups in this model of second intention wound healing. This was unexpected due to the established effects of UMF 20 manuka honey on wound healing using the same model. This may be due to systemic effects of cannabidiol and study design. Further research into the use of cannabidiol in equine wounds is warranted.

Supercritical carbon dioxide Cannabis sativa L. and Humulus lupulus extracts and their influence on human macrophages inflammatory state*

Herbal extracts are promising immunomodulating compounds. Their standardization may improve clinical outcome in various conditions related to inflammatory state. The aim of this study was to assess the utility of Cannabis sativa L. and Humulus lupulus extracts obtained by supercritical carbon dioxide (scCO2) in the reduction of pro-inflammatory cytokines release after LPS stimulation in the in vitro model. After scCO2 extraction, the cytotoxic potential of the obtained compounds was determined. The highest non-cytotoxic concentrations were selected for further inflammatory testing. PMA-differentiated U937 cells were used as an LPS induced model of the inflammation to assess the extracts potential to decrease the level of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α. Either individually tested or in combination scCO2 extracts markedly reduced the level of released pro-inflammatory cytokines in comparison to LPS stimulated positive control. Our results show that the usage of standardized Cannabis sativa L. and Humulus lupulus extracts might be beneficial in reducing the inflammatory state. Application of the mixed extracts not only reduces the need for a high concentration of pure compounds, but also broadens the possible therapeutic effect. Moreover, scCO2 extraction may serve as the efficient method of obtaining functional anti-inflammatory extracts from either hop cones or cannabis.

Marijuana-Derived Cannabinoids Trigger a CB2/PI3K Axis of Suppression of the Innate Response to Oral Pathogens

Cannabis use is an emergent risk factor for periodontitis, a chronic bacterial-induced disease of the supporting structures of the teeth. However, the mechanisms by which marijuana exposure predisposes to periodontal tissue destruction have yet to be elucidated. Therefore, we examined the influence of physiologically relevant doses of major marijuana-derived phytocannabinoid subtypes (cannabidiol [CBD]; cannabinol [CBN]; and tetrahydrocannabinol [THC], 1.0 μg/ml) on the interactions of three ultrastructurally variant oral pathogens, Porphyromonas gingivalis, Filifactor alocis, and Treponema denticola with the immune system. CBD, CBN, and THC each suppressed P. gingivalis-induced IL-12 p40, IL-6, IL-8, and TNF release while enhancing the anti-inflammatory cytokine, IL-10, from human innate cells. Similar phenomena were observed in F. alocis- and T. denticola-exposed human monocytes and human gingival keratinocytes. Higher phytocannabinoid doses (≥5.0 μg/ml) compromised innate cell viability and inhibited the growth of P. gingivalis and F. alocis, relative to unexposed bacteria. T. denticola, however, was resistant to all cannabinoid doses tested (up to 10.0 μg/ml). Pharmaceutical inhibition and efficient gene silencing indicated that a common CB2/PI3K axis of immune suppression is triggered by phytocannabinoids in vitro. This pathway does not appear to perpetuate through the canonical GSK3β-dependent cholinergic anti-inflammatory pathway, the predominant endogenous inflammatory control system. In a repetitive, transient oral infection model, CBD also suppressed P. gingivalis-induced innate immune markers in wild-type mice, but not in CB2^−/− mice. If such phenomena occur in humans in situ, environmental cannabinoids may enhance periodontitis via direct toxic effects on specific oral bacteria; by compromising innate cell vitality; and/or through a suppressed innate response to periodontal pathogens involving a CB2/PI3K signaling lineage.

Pure Δ9-tetrahydrocannabivarin and a Cannabis sativa extract with high content in Δ9-tetrahydrocannabivarin inhibit nitrite production in murine peritoneal macrophages

Historical and scientific evidence suggests that Cannabis use has immunomodulatory and anti-inflammatory effects. We have here investigated the effect of the non-psychotropic phytocannabinoid Δ⁹-tetrahydrocannabivarin (THCV) and of a Cannabis sativa extract with high (64.8%) content in THCV (THCV-BDS) on nitric oxide (NO) production, and on cannabinoid and transient receptor potential (TRP) channel expression in lipopolysaccharide (LPS)-stimulated murine peritoneal macrophages. THCV-BDS and THCV exhibited similar affinity in radioligand binding assays for CB₁ and CB₂ receptors, and inhibited, via CB₂ but not CB₁ cannabinoid receptors, nitrite production evoked by LPS in peritoneal macrophages. THCV down-regulated the over-expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and interleukin 1β (IL-1β) proteins induced by LPS. Furthermore, THCV counteracted LPS-induced up-regulation of CB₁ receptors, without affecting the changes in CB₂, TRPV2 or TRPV4 mRNA expression caused by LPS. Other TRP channels, namely, TRPA1, TRPV1, TRPV3 and TRPM8 were poorly expressed or undetectable in both unstimulated and LPS-challenged macrophages. It is concluded that THCV - via CB₂ receptor activation - inhibits nitrite production in macrophages. The effect of this phytocannabinoid was associated with a down-regulation of CB₁, but not CB₂ or TRP channel mRNA expression.

HU-444, a Novel, Potent Anti-Inflammatory, Nonpsychotropic Cannabinoid

Cannabidiol (CBD) is a component of cannabis, which does not cause the typical marijuana-type effects, but has a high potential for use in several therapeutic areas. In contrast to Δ(9)-tetrahydrocannabinol (Δ(9)-THC), it binds very weakly to the CB1 and CB2 cannabinoid receptors. It has potent activity in both in vitro and in vivo anti-inflammatory assays. Thus, it lowers the formation of tumor necrosis factor (TNF)-α, a proinflammatory cytokine, and was found to be an oral antiarthritic therapeutic in murine collagen-induced arthritis in vivo. However, in acidic media, it can cyclize to the psychoactive Δ(9)-THC. We report the synthesis of a novel CBD derivative, HU-444, which cannot be converted by acid cyclization into a Δ(9)-THC-like compound. In vitro HU-444 had anti-inflammatory activity (decrease of reactive oxygen intermediates and inhibition of TNF-α production by macrophages); in vivo it led to suppression of production of TNF-α and amelioration of liver damage as well as lowering of mouse collagen-induced arthritis. HU-444 did not cause Δ(9)-THC-like effects in mice. We believe that HU-444 represents a potential novel drug for rheumatoid arthritis and other inflammatory diseases.

The cannabinoid TRPA1 agonist cannabichromene inhibits nitric oxide production in macrophages and ameliorates murine colitis

BACKGROUND AND PURPOSE

The non-psychotropic cannabinoid cannabichromene is known to activate the transient receptor potential ankyrin-type1 (TRPA1) and to inhibit endocannabinoid inactivation, both of which are involved in inflammatory processes. We examined here the effects of this phytocannabinoid on peritoneal macrophages and its efficacy in an experimental model of colitis.

EXPERIMENTAL APPROACH

Murine peritoneal macrophages were activated in vitro by LPS. Nitrite levels were measured using a fluorescent assay; inducible nitric oxide (iNOS), cyclooxygenase-2 (COX-2) and cannabinoid (CB1 and CB2 ) receptors were analysed by RT-PCR (and/or Western blot analysis); colitis was induced by dinitrobenzene sulphonic acid (DNBS). Endocannabinoid (anandamide and 2-arachidonoylglycerol), palmitoylethanolamide and oleoylethanolamide levels were measured by liquid chromatography-mass spectrometry. Colonic inflammation was assessed by evaluating the myeloperoxidase activity as well as by histology and immunohistochemistry.

KEY RESULTS

LPS caused a significant production of nitrites, associated to up-regulation of anandamide, iNOS, COX-2, CB1 receptors and down-regulation of CB2 receptors mRNA expression. Cannabichromene significantly reduced LPS-stimulated nitrite levels, and its effect was mimicked by cannabinoid receptor and TRPA1 agonists (carvacrol and cinnamaldehyde) and enhanced by CB1 receptor antagonists. LPS-induced anandamide, iNOS, COX-2 and cannabinoid receptor changes were not significantly modified by cannabichromene, which, however, increased oleoylethanolamide levels. In vivo, cannabichromene ameliorated DNBS-induced colonic inflammation, as revealed by histology, immunohistochemistry and myeloperoxidase activity.

CONCLUSION AND IMPLICATIONS

Cannabichromene exerts anti-inflammatory actions in activated macrophages - with tonic CB1 cannabinoid signalling being negatively coupled to this effect - and ameliorates experimental murine colitis.

Cannabis use provides symptom relief in patients with inflammatory bowel disease but is associated with worse disease prognosis in patients with Crohn's disease

BACKGROUND

Cannabinoids are used by patients with inflammatory bowel disease (IBD) to alleviate their symptoms. Little is known on patient motivation, benefit, or risks of this practice. Our aim was to assess the extent and motives for Cannabis use in patients with IBD and the beneficial and adverse effects associated with self-administration of Cannabis.

METHODS

Consecutive patients with IBD (n = 313) seen in the University of Calgary from July 2008 to March 2009 completed a structured anonymous questionnaire covering motives, pattern of use, and subjective beneficial and adverse effects associated with self-administration of Cannabis. Subjects who had used Cannabis specifically for the treatment of IBD or its symptoms were compared with those who had not. Logistic regression analysis was used to identify variables predictive of poor IBD outcomes, specifically surgery or hospitalization for IBD.

RESULTS

Cannabis had been used by 17.6% of respondents specifically to relieve symptoms associated with their IBD, the majority by inhalational route (96.4%). Patients with IBD reported that Cannabis improved abdominal pain (83.9%), abdominal cramping (76.8%), joint pain (48.2%), and diarrhea (28.6%), although side effects were frequent. The use of Cannabis for more than 6 months at any time for IBD symptoms was a strong predictor of requiring surgery in patients with Crohn's disease (odds ratio = 5.03, 95% confidence interval = 1.45-17.46) after correcting for demographic factors, tobacco smoking status, time since IBD diagnosis, and biological use. Cannabis was not a predictor for hospitalization for IBD in the previous year.

CONCLUSIONS

Cannabis use is common in patients with IBD and subjectively improved pain and diarrheal symptoms. However, Cannabis use was associated with higher risk of surgery in patients with Crohn's disease. Patients using Cannabis should be cautioned about potential harm, until clinical trials evaluate efficacy and safety.

In vitro metabolism and metabolic effects of ajulemic acid, a synthetic cannabinoid agonist

Ajulemic acid is a synthetic analog of Δ⁸-THC-11-oic acid, the terminal metabolite of Δ⁸-THC. Unlike Δ⁹-THC, the psychoactive principle of Cannabis, it shows potent anti-inflammatory action and has minimal CNS cannabimimetic activity. Its in vitro metabolism by hepatocytes from rats, dogs, cynomolgus monkeys and humans was studied and the results are reported here. Five metabolites, M1 to M5, were observed in human hepatocyte incubations. One metabolite, M5, a glucuronide, was observed in the chromatogram of canine hepatocyte incubations. In monkey hepatocyte incubations, M5 was observed in the chromatograms of both the 120 and 240 min samples, trace metabolite M1 (side-chain hydroxyl) was observed in the 120 min samples, and trace metabolite M4 (side-chain dehydrogenation) was observed in the 240 min samples. No metabolites were found in the rat hepatocyte incubations. Unchanged amounts of ajulemic acid detected after the 2-h incubation were 103%, 90%, 86%, and 83% for rat, dog, monkey, and human hepatocytes, respectively. Additional studies were done to ascertain if ajulemic acid can inhibit the activities of five principal human cytochrome P450 isozymes; CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4/5. In contrast to the phytocannabinoids Δ⁹-THC and CBD, no significant inhibition of cytochrome activity was observed. These data further support the conclusions reached in earlier reports on ajulemic acid's high margin of safety and suggest that it undergoes minimal metabolism and is not likely to interfere with the normal metabolism of drugs or endogenous substances.

Cannabinoid receptor-2 (CB2) agonist ameliorates colitis in IL-10(-/-) mice by attenuating the activation of T cells and promoting their apoptosis

Inflammatory bowel disease (IBD) is a chronic intestinal inflammation caused by hyperactivated effector immune cells that produce pro-inflammatory cytokines. Recent studies have shown that the cannabinoid system may play a critical role in mediating protection against intestinal inflammation. However, the effect of cannabinoid receptor induction after chronic colitis progression has not been investigated. Here, we investigate the effect of cannabinoid receptor-2 (CB2) agonist, JWH-133, after chronic colitis in IL-10(-/-) mice. JWH-133 effectively attenuated the overall clinical score, and reversed colitis-associated pathogenesis and decrease in body weight in IL-10(-/-) mice. After JWH-133 treatment, the percentage of CD4(+) T cells, neutrophils, mast cells, natural killer (NK1.1) cells, and activated T cells declined in the intestinal lamina propria (LP) and mesenteric lymph nodes (MLN) of mice with chronic colitis. JWH-133 was also effective in ameliorating dextran sodium sulfate (DSS)-induced colitis. In this model, JWH-133 reduced the number and percentage of macrophages and IFN-γ expressing cells that were induced during colitis progression. Treatment with aminoalkylindole 6-iodo-pravadoline (AM630), a CB2 receptor antagonist, reversed the colitis protection provided by JWH-133 treatment. Also, activated T cells were found to undergo apoptosis following JWH-133 treatment both in-vivo and in-vitro. These findings suggest that JWH-133 mediates its effect through CB2 receptors, and ameliorates chronic colitis by inducing apoptosis in activated T cells, reducing the numbers of activated T cells, and suppressing induction of mast cells, NK cells, and neutrophils at sites of inflammation in the LP. These results support the idea that the CB2 receptor agonists may serve as a therapeutic modality against IBD.

Systematic review of herbals as potential anti-inflammatory agents: Recent advances, current clinical status and future perspectives

Many synthetic drugs reported to be used for the treatment of inflammatory disorders are of least interest now a days due to their potential side effects and serious adverse effects and as they are found to be highly unsafe for human assistance. Since the last few decades, herbal drugs have regained their popularity in treatment against several human ailments. Herbals containing anti-inflammatory activity (AIA) are topics of immense interest due to the absence of several problems in them, which are associated with synthetic preparations. The primary objective of this review is to provide a deep overview of the recently explored anti-inflammatory agents belonging to various classes of phytoconstituents like alkaloids, glycosides, terpenoids, steroids, polyphenolic compounds, and also the compounds isolated from plants of marine origin, algae and fungi. Also, it enlists a distended view on potential interactions between herbals and synthetic preparations, related adverse effects and clinical trials done on herbals for exploring their AIA. The basic aim of this review is to give updated knowledge regarding plants which will be valuable for the scientists working in the field of anti-inflammatory natural chemistry.

Pharmacological evaluation of the natural constituent of Cannabis sativa, cannabichromene and its modulation by Δ(9)-tetrahydrocannabinol

In contrast to the numerous reports on the pharmacological effects of Δ(9)-tetrahydrocannabinol (THC), the pharmacological activity of another substituent of Cannabis sativa, cannabichromene (CBC) remains comparatively unknown. In the present study, we investigated whether CBC elicits cannabinoid activity in the tetrad assay, which consists of the following four endpoints: hypomotility, antinociception, catalepsy, and hypothermia. Because cannabinoids are well documented to possess anti-inflammatory properties, we examined CBC, THC, and combination of both phytocannabinoids in the lipopolysaccharide (LPS) paw edema assay. CBC elicited activity in the tetrad that was not blocked by the CB(1) receptor antagonist, rimonabant. Moreover, a behaviorally inactive dose of THC augmented the effects of CBC in the tetrad that was associated with an increase in THC brain concentrations. Both CBC and THC elicited dose-dependent anti-inflammatory effects in the LPS-induced paw edema model. The CB(2) receptor, SR144528 blocked the anti-edematous actions of THC, but not those produced by CBC. Isobolographic analysis revealed that the anti-edematous effects of these cannabinoids in combination were additive. Although CBC produced pharmacological effects, unlike THC, its underlying mechanism of action did not involve CB(1) or CB(2) receptors. In addition, there was evidence of a possible pharmacokinetic component in which CBC dose-dependently increased THC brain levels following an i.v. injection of 0.3mg/kg THC. In conclusion, CBC produced a subset of behavioral activity in the tetrad assay and reduced LPS-induced paw edema through a noncannabinoid receptor mechanism of action. These effects were augmented when CBC and THC were co-administered.

Deciphering the mechanism(s) of action of natural products: analgesic peroxide oil as example

BACKGROUND

There are multiple reports of natural products having therapeutic effect. In an era of evidence-based medicine, clinical trials inform clinical decisions regarding use of the product, but prevailing preference is to identify and use a single 'active ingredient'. Yet, the clinical benefit of a natural product might derive from the fortuitous combination of its multiple components. Therefore, the elucidation of the mechanism(s) of action of natural products is important, but presents significant challenges. This article examines this issue using peroxide oil (essential oxygen oil) as an illustrative example.

OBJECTIVE

To review the published literature of a natural product in an effort to elucidate postulated mechanism(s) of action of a complex mixture.

METHODS

The clinical and preclinical literature was reviewed from the perspective of its contribution to elucidating a mechanism of analgesic action of a natural product.

RESULTS

Peroxide oil contains ingredients that are associated with analgesic mechanisms, such inhibition of lipid peroxidation and arachidonic acid metabolism and non-opioid, glibenclamide-sensitive receptor-mediated and K(ATP) -NO-cGMP channel pathways.

CONCLUSION

Although its exact mechanism remains unknown, peroxide oil provides an example of how a natural product can be evaluated for plausible mechanistic explanation of its purported therapeutic efficacy. Such an approach seems valuable, since, as in this case, the constituents appear to contribute in an additive or synergistic manner, something not possible with a single substance.

Immunoactive effects of cannabinoids: considerations for the therapeutic use of cannabinoid receptor agonists and antagonists

The active constituents of Cannabis sativa have been used for centuries as recreational drugs and medicinal agents. Today, marijuana is the most prevalent drug of abuse in the United States and, conversely, therapeutic use of marijuana constituents are gaining mainstream clinical and political acceptance. Given the documented contributions of endocannabinoid signaling to a range of physiological systems, including cognitive function, and the control of eating behaviors, it is unsurprising that cannabinoid receptor agonists and antagonists are showing significant clinical potential. In addition to the neuroactive effects of cannabinoids, an emerging body of data suggests that both endogenous and exogenous cannabinoids are potently immunoactive. The central premise of this review article is that the immunological effects of cannabinoids should be considered in the context of each prescribing decision. We present evidence that the immunological effects of cannabinoid receptor agonists and antagonists are highly relevant to the spectrum of disorders for which cannabinoid therapeutics are currently offered.

Cannabinoids prevent the opposite regulation of astroglial connexin43 hemichannels and gap junction channels induced by pro-inflammatory treatments

Brain injuries as well as neurodegenerative diseases, are associated with neuro-inflammation characterized by astroglial and microglial activation and/or proliferation. Recently, we reported that lipopolysaccharide (LPS)-activation of microglia inhibits junctional channels and promotes hemichannels, two connexin43 functions in astrocytes. This opposite regulation is mediated by two pro-inflammatory cytokines, interleukin-1 beta and tumor necrosis factor-alpha, released from activated microglia. Because cannabinoids (CBs) have anti-inflammatory properties and their receptors are expressed by glial cells, we investigated on primary cortical cultures the effects of CB agonists, methanandamide and synthetic CBs on (i) cytokines released from LPS-activated microglia and (ii) connexin43 functions in astrocytes subjected to pro-inflammatory treatments. We observed that CBs inhibited the LPS-induced release of interleukin-1 beta and tumor necrosis factor-alpha from microglia. Moreover, the connexin43 dual regulation evoked by the pro-inflammatory treatments, was prevented by CB treatments. Pharmacological characterizations of CB actions on astrocytic connexin43 channels revealed that these effects were mainly mediated through CB1 receptors activation, although non-CB1/CB2 receptors seemed to mediate the action of the methanandamide. Altogether these data demonstrate that in inflammatory situations CBs exert, through the activation of different sub-types of glial CB receptors, a regulation on two functions of connexin43 channels in astrocytes known to be involved in neuron survival.

Cannabinoids inhibit fibrogenesis in diffuse systemic sclerosis fibroblasts

OBJECTIVE

It has been demonstrated that the endocannabinoid system is up-regulated in pathologic fibrosis and that modulation of the cannabinoid receptors might limit the progression of uncontrolled fibrogenesis. The aim of this study was to investigate whether the synthetic cannabinoid receptor agonist WIN55,212-2 could modulate fibrogenesis in an in vitro model of dcSSc.

METHODS

The expression of cannabinoid receptors CB1 and CB2 was assessed in dcSSc fibroblasts and healthy control fibroblasts. To investigate the effect of WIN55,212-2 on dcSSc fibrogenesis, we studied type I collagen, profibrotic cytokines, fibroblast transdifferentiation into myofibroblasts, apoptotic processes and activation of the extracellular signal-related kinase 1/2 pathway prior to and after the treatment with the synthetic cannabinoid at increasing concentrations.

RESULTS

Both CB1 and CB2 receptors were over-expressed in dcSSc fibroblasts compared with healthy controls. WIN55,212-2 caused a reduction in extracellular matrix deposition and counteracted several behavioural abnormalities of scleroderma fibroblasts including transdifferentiation into myofibroblasts and resistance to apoptosis. The anti-fibrogenic effect of WIN55,212-2 was not reverted by selective cannabinoid antagonists.

CONCLUSIONS

Our preliminary findings suggest that cannabinoids are provided with an anti-fibrotic activity, thereby possibly representing a new class of agents targeting fibrosis diseases.

Cannabinoids, endocannabinoids, and related analogs in inflammation

This review covers reports published in the last 5 years on the anti-inflammatory activities of all classes of cannabinoids, including phytocannabinoids such as tetrahydrocannabinol and cannabidiol, synthetic analogs such as ajulemic acid and nabilone, the endogenous cannabinoids anandamide and related compounds, namely, the elmiric acids, and finally, noncannabinoid components of Cannabis that show anti-inflammatory action. It is intended to be an update on the topic of the involvement of cannabinoids in the process of inflammation. A possible mechanism for these actions is suggested involving increased production of eicosanoids that promote the resolution of inflammation. This differentiates these cannabinoids from cyclooxygenase-2 inhibitors that suppress the synthesis of eicosanoids that promote the induction of the inflammatory process.

Ajulemic acid, a synthetic cannabinoid, increases formation of the endogenous proresolving and anti-inflammatory eicosanoid, lipoxin A4

Ajulemic acid (AjA), a synthetic nonpsychoactive cannabinoid, and lipoxin A(4) (LXA(4)), an eicosanoid formed from sequential actions of 5- and 15-lipoxygenases (LOX), facilitate resolution of inflammation. The purpose of this study was to determine whether the ability of AjA to limit the progress of inflammation might relate to an increase in LXA(4), a known anti-inflammatory and proresolving mediator. Addition of AjA (0-30 microM) in vitro to human blood and synovial cells increased production of LXA(4) (ELISA) 2- to 5-fold. Administration of AjA to mice with peritonitis resulted in a 25-75% reduction of cells invading the peritoneum, and a 7-fold increase in LXA(4) identified by mass spectrometry. Blockade of 12/15 LOX, which leads to LXA(4) synthesis via 15-HETE production, reduced (>90%) the ability of AjA to enhance production of LXA(4) in vitro. These results suggest that AjA and other agents that increase endogenous compounds that facilitate resolution of inflammation may be useful for conditions characterized by inflammation and tissue injury.

Suppression of human macrophage interleukin-6 by a nonpsychoactive cannabinoid acid

Interleukin-6 (IL-6) is a multifunctional cytokine which contributes to inflammation and tissue injury in several diseases. Thus, inhibition of IL-6 production may be a useful strategy for treatment of patients with diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). A synthetic nonpsychoactive cannabinoid, ajulemic acid (AjA), prevents joint damage in experimental arthritis. Results of experiments presented here indicate that addition of AjA (3-30 microM) to human monocyte derived macrophages in vitro reduces steady state levels of IL-6 mRNA and the subsequent secretion of IL-6 from LPS stimulated cells. Although AjA binds to and activates PPARgamma, its anti IL-6 effects are PPARgamma independent. These studies provide evidence to support the view that AjA may prove to be an effective, safe antiinflammatory agent.

The elmiric acids: biologically active anandamide analogs

As chemical entities, lipoamino acids have been known for some time. However, more recently their occurrence and importance in mammalian species has been discovered. They appear to have close relationships with the endocannabinoids not only structurally but also in terms of biological actions. The latter include analgesia, anti-inflammatory effects, inhibition of cell proliferation and calcium ion mobilization. To date about 40 naturally occurring members of this family have been identified and, additionally, several synthetic analogs have been prepared and studied. To facilitate their identity, a nomenclature system has been suggested based on the name elmiric acid (EMA). The prototypic example, N-arachidonoyl glycine, does not bind to CB1, however it does inhibit the glycine transporter GLYT2a and also appears to be a ligand for the orphan G-protein-coupled receptor GPR18. It may also have a role in regulating tissue levels of anandamide by virtue of its inhibitory effect on FAAH the enzyme that mediates inactivation of anandamide. Its concentration in rat brain is several-fold higher than anandamide supporting its possible role as a physiological mediator. Future studies should be aimed at elucidating the actions of all of the members of this interesting family of molecules.

Potential anti-inflammatory actions of the elmiric (lipoamino) acids

A library of amino acid-fatty acid conjugates (elmiric acids) was synthesized and evaluated for activity as potential anti-inflammatory agents. The compounds were tested in vitro for their effects on cell proliferation and prostaglandin production, and compared with their effects on in vivo models of inflammation. LPS stimulated RAW 267.4 mouse macrophage cells were the in vitro model and phorbol ester-induced mouse ear edema served as the principal in vivo model. The prostaglandin responses were found to be strongly dependent on the nature of the fatty acid part of the molecule. Polyunsaturated acid conjugates produced a marked increase in media levels of i15-deoxy-PGJ(2) with minimal effects on PGE production. It is reported in the literature that prostaglandin ratios in which the J series predominates over the E series promote the resolution of inflammatory conditions. Several of the elmiric acids tested here produced such favorable ratios suggesting that their potential anti-inflammatory activity occurs via a novel mechanism of action. The ear edema assay results were generally in agreement with the prostaglandin assay findings indicating a connection between them.

Ajulemic acid, a nonpsychoactive cannabinoid acid, suppresses osteoclastogenesis in mononuclear precursor cells and induces apoptosis in mature osteoclast-like cells

Oral administration of ajulemic acid (AjA), a cannabinoid acid devoid of psychoactivity, prevents joint tissue injury in rats with adjuvant induced arthritis. Because activation of osteoclasts is central to the pathogenesis of bone erosion in patients with rheumatoid arthritis (RA), we investigated the influence of AjA on osteoclast differentiation and survival. Osteoclast cultures were established by stimulation of RAW264.7 cells and primary mouse bone marrow cultures with receptor activator of NF-kappaB ligand (RANKL). Simultaneous addition of AjA (15 and 30 microM) and RANKL to both culture systems significantly suppressed development of multinucleated osteoclasts (osteoclastogenesis) in a dose dependent manner, as determined by quantification of multinuclear, tartrate-resistant acid phosphatase (TRAP)-positive cells. AjA impaired growth of RAW264.7 monocytes and prevented further osteoclast formation in cultures in which osteoclastogenesis had already begun. Reduction by AjA of both monocyte growth and osteoclast formation was associated with apoptosis, assayed by annexin V and propidium iodide staining, and caspase activity. The anti-osteoclastogenic effects of AjA did not require the continuous presence of AjA in the cell cultures. Based on these findings, we propose that AjA or other nonpsychoactive synthetic analogs of Cannabis constituents may be useful therapy for diseases such as RA and osteoporosis in which bone resorption is a central feature.

The application of DNA micro-arrays (gene arrays) to the study of herbal medicines

DNA micro-arrays (gene arrays) have become a popular and useful tool with which to study the effects of various agents and treatments on gene expression in cells and tissues. In theory one can simultaneously evaluate, in a single experiment, changes in gene expression (at the level of transcription) of the entire genome of the organism under study. Consequently these techniques have been used by many investigators interested in cancer research, differentiation and development, toxicology, and the effects of pharmaceuticals on cells and animals. In addition, recent studies have shown the capacity of the technique for revealing the importance of genes not previously implicated in a given response. However, relatively few attempts have been made so far to evaluate herbal medicines, although the potential to answer a number of relevant questions is there. In this review we first discuss the fundamental principles of the gene array technology, focusing on the individual steps in the process and their problems and pitfalls, and we discuss the analysis and interpretation of the data, the discipline of bio-informatics, without which meaningful evaluation of gene expression changes would be impossible. We next analyze specific studies, which utilized gene array technology, aimed at evaluating the effects of certain herbal medicine formulas and bioactive ingredients in animal tissues and in cell cultures. We also include a brief description of our own evaluation of Echinacea, which we have been studying for several years, to indicate possible mechanisms of action of this herbal, and also to illustrate how the techniques, especially the bio-informatics, continue to evolve. We believe, on the basis of experience acquired by us and other investigators to date, that the technology of gene array analysis can make significant contributions to understanding how herbal medicines work, and therefore can validate their applications in medicine.

N-arachidonoyl L-serine, an endocannabinoid-like brain constituent with vasodilatory properties

The endocannabinoid N-arachidonoyl ethanolamine (anandamide), found both in the CNS and in the periphery, plays a role in numerous physiological systems. One might expect that the chemically related N-arachidonoyl-L-serine (ARA-S) could also be formed alongside anandamide. We have now isolated ARA-S from bovine brain and elucidated its structure by comparison with synthetic ARA-S. Contrary to anandamide, ARA-S binds very weakly to cannabinoid CB1 and CB2 or vanilloid TRPV1 (transient receptor potential vanilloid 1) receptors. However, it produces endothelium-dependent vasodilation of rat isolated mesenteric arteries and abdominal aorta and stimulates phosphorylation of p44/42 mitogen-activated protein (MAP) kinase and protein kinase B/Akt in cultured endothelial cells. ARA-S also suppresses LPS-induced formation of TNF-alpha in a murine macrophage cell line and in wild-type mice, as well as in mice deficient in CB1 or CB2 receptors. Many of these effects parallel those reported for abnormal cannabidiol (Abn-CBD), a synthetic agonist of a putative novel cannabinoid-type receptor. Hence, ARA-S may represent an endogenous agonist for this receptor.

CANNABINOID RECEPTORS AS THERAPEUTIC TARGETS

CB1 and CB2 cannabinoid receptors are the primary targets of endogenous cannabinoids (endocannabinoids). These G protein-coupled receptors play an important role in many processes, including metabolic regulation, craving, pain, anxiety, bone growth, and immune function. Cannabinoid receptors can be engaged directly by agonists or antagonists, or indirectly by manipulating endocannabinoid metabolism. In the past several years, it has become apparent from preclinical studies that therapies either directly or indirectly influencing cannabinoid receptors might be clinically useful. This review considers the components of the endocannabinoid system and discusses some of the most promising endocannabinoid-based therapies.

Cannabinoids, loratadine and allopurinol as novel additions to the antipsoriatic ammunition

As the current antipsoriatic medications are commonly associated with deleterious side-effects, a determined search for safer agents, which could be used alone or in combination with current antipsoriatic drugs, would be very imperative. Psoriasis is believed to be characterized by a type 1 cytokine pattern; interferon-gamma, interleukin (IL)-2 and tumour necrosis factor (TNF)-alpha are predominantly expressed in this disorder. Nitric oxide, reactive oxygen species, histamine, leukotriene B4, and decreased [corrected] keratinocyte cyclic adenosine monophosphate/cyclic guanosine monophosphate (cAMP/cGMP) ratio are supposed to play roles in the pathogenesis of this disorder. Based on the immunopathogenesis of psoriasis, this paper introduces three novel, potential treatments for this clinical conundrum: (i) cannabinoids, which exert inhibitory effects on antigen processing and macrophage/T-cell interaction and also on the release of IL-2, TNF-alpha and nitric oxide from immune cells; (ii) loratadine, which is an antihistamine capable of increasing [corrected] the cAMP/cGMP ratio and the production of leukotriene B4; and (iii) allopurinol, which scavenges free radicals, inhibits the production of TNF-alpha, and downregulates the expression of intercellular adhesion molecule-1 and P2X7 receptors on monocytes/macrophages, which are involved in antigen presentation and production of the inflammatory response, respectively. Importantly, allopurinol, especially in combination with cyclosporin, has been shown to be effective against experimental autoimmune uveitis, which, like psoriasis, is a cell-mediated autoimmune disorder.

The endogenous cannabinoid system protects against colonic inflammation

Excessive inflammatory responses can emerge as a potential danger for organisms' health. Physiological balance between pro- and anti-inflammatory processes constitutes an important feature of responses against harmful events. Here, we show that cannabinoid receptors type 1 (CB1) mediate intrinsic protective signals that counteract proinflammatory responses. Both intrarectal infusion of 2,4-dinitrobenzene sulfonic acid (DNBS) and oral administration of dextrane sulfate sodium induced stronger inflammation in CB1-deficient mice (CB1(-/-)) than in wild-type littermates (CB1(+/+)). Treatment of wild-type mice with the specific CB1 antagonist N-(piperidino-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-pyrazole-3-carboxamide (SR141716A) mimicked the phenotype of CB1(-/-) mice, showing an acute requirement of CB1 receptors for protection from inflammation. Consistently, treatment with the cannabinoid receptor agonist R(-)-7-hydroxy-Delta(6)-tetra-hydrocannabinol-dimethylheptyl (HU210) or genetic ablation of the endocannabinoid-degrading enzyme fatty acid amide hydrolase (FAAH) resulted in protection against DNBS-induced colitis. Electrophysiological recordings from circular smooth muscle cells, performed 8 hours after DNBS treatment, revealed spontaneous oscillatory action potentials in CB1(-/-) but not in CB1(+/+) colons, indicating an early CB1-mediated control of inflammation-induced irritation of smooth muscle cells. DNBS treatment increased the percentage of myenteric neurons expressing CB1 receptors, suggesting an enhancement of cannabinoid signaling during colitis. Our results indicate that the endogenous cannabinoid system represents a promising therapeutic target for the treatment of intestinal disease conditions characterized by excessive inflammatory responses.

Cannabinoids in multiple sclerosis: do they have a therapeutic role?

This is an exciting time for cannabinoid research. Evidence suggests that cannabis (marijuana) can alleviate symptoms like muscle spasticity and pain in patients with multiple sclerosis (MS). Interest in the field of cannabinoids has been strengthened by the identification and cloning of cannabinoid receptors located in the central nervous system and the peripheral immune organs, and by the discovery of the endogenous cannabinoid ligands. Cannabinoids are also efficacious in animal models of MS. However, there have been only ten published clinical reports on the use of cannabis in MS, involving 78 individuals worldwide, and the results have been equivocal. Researchers encounter a number of difficulties in designing clinical studies that use cannabinoids. From the studies reporting the use of cannabinoids in MS patients with spasticity, the somewhat better designed studies failed to demonstrate objective improvement. Therefore, convincing evidence that cannabinoids are effective in MS is still lacking.

Cannabinoids and glaucoma

Glaucoma is one of the leading causes of blindness in the world. In spite of the diverse therapeutic possibilities, new and better treatments for glaucoma are highly desirable. Cannabinoids effectively lower the intraocular pressure (IOP) and have neuroprotective actions. Thus, they could potentially be useful in the treatment of glaucoma. The purpose of this article is to provide the reader with an overview of the latest achievements in research into the potential use of cannabinoids for glaucoma.