Cannabigerol (CBG) attenuates mechanical hypersensitivity elicited by chemotherapy-induced peripheral neuropathy

Systematic biotechnological production of isoprenoid analogs with bespoke carbon skeletons

Natural products are widely used as pharmaceuticals, flavors, fragrances, and cosmetic ingredients. Synthesizing and evaluating analogs of natural products can considerably expand their applications. However, the chemical synthesis of analogs of natural products is severely hampered by their highly complex structures. This is particularly evident in isoprenoids, the largest class of natural products. Here, we develop a yeast cell-based biocatalytic method that enables the systematic biotechnological production of analogs of different classes of isoprenoids (including monoterpenoids, sesquiterpenoids, triterpenoids, and cannabinoids) with additional carbons in their skeletons. We demonstrate the applicability of this approach through two proof-of-concept studies: the biosynthesis of the highly valued aroma ingredient ethyllinalool, and the production of cannabinoid analogs with improved cannabinoid receptor agonism. This method is simple, readily adaptable to any cell factory, and enables the tailored expansion of the isoprenoid chemical space to identify molecules with improved properties and the biotechnological production of valuable compounds.

ART26.12, a novel fatty acid-binding protein 5 inhibitor, shows efficacy in multiple preclinical neuropathy models

BACKGROUND

Painful neuropathy is a pathological condition caused by numerous factors including diabetes, chemotherapy or cancer. ART26.12 is a novel fatty acid-binding protein 5 inhibitor, which our group showed could prevent and treat persistent pain in a preclinical model of oxaliplatin-induced peripheral neuropathy.

METHODS

In the current study, the efficacy of orally dosed ART26.12 was tested in multiple neuropathy models of different aetiology. Paw withdrawal threshold to von Frey monofilaments and latency to escape a cold plate were used as measurements of mechanical and cold sensitivity.

RESULTS

ART26.12 (25 and 50 mg/kg BID), dosed prior to the induction of paclitaxel-induced peripheral neuropathy (PIPN), reversed mechanical allodynia induced by paclitaxel in both male and female rats, and ART26.12 (50 mg/kg BID) prevented the induction of PIPN in female rats. ART26.12 (50 mg/kg BID) also had a protective effect on body weight in the PIPN model. ART26.12 (25 and 100 mg/kg BID) reversed mechanical allodynia when treating established streptozotocin-induced diabetic neuropathy in male rats. In a model of breast cancer-induced bone pain in female rats, ART26.12 (100 mg/kg BID) reversed mechanical allodynia within 1 h of dosing. In the same model, ART26.12 (25 mg/kg BID) reversed mechanical allodynia from day 4 of treatment.

CONCLUSION

Overall, these preclinical data suggest that ART26.12 is a safe and efficacious therapeutic drug for continued development towards the prevention and treatment of peripheral neuropathy.

SIGNIFICANCE STATEMENT

This work now shows that ART26.12, a novel and selective inhibitor of FABP5, can prevent and treat multiple preclinical models of peripheral neuropathy. Given its excellent safety profile, further work is warranted to develop ART26.12 as a potential therapeutic tool for pain management.

Nav1.8, an analgesic target for nonpsychotomimetic phytocannabinoids

Pain impacts billions of people worldwide, but treatment options are limited and have a spectrum of adverse effects. The search for safe and nonaddictive pain treatments has led to a focus on key mediators of nociceptor excitability. Voltage-gated sodium (Nav) channels in the peripheral nervous system-Nav1.7, Nav1.8, and Nav1.9-play crucial roles in pain signaling. Among these, Nav1.8 has shown promise due to its rapid recovery from inactivation and role in repetitive firing, with recent clinical studies providing proof-of-principal that block of Nav1.8 can reduce pain in humans. We report here that three nonpsychotomimetic cannabinoids-cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN)-effectively inhibit Nav1.8, suggesting their potential as analgesic compounds. In particular, CBG shows significant promise due to its ability to effectively inhibit excitability of peripheral sensory neurons. These findings highlight the therapeutic potential of cannabinoids, particularly CBG, as agents that may attenuate pain via block of Nav1.8, warranting further in vivo studies.

Animal models of cisplatin-induced neuropathic pain

Cisplatin chemotherapy has been used as the main treatment for different types of cancer. However, cisplatin chemotherapy-induced peripheral neuropathic pain (CIPNP) seriously affects the treatment process and quality of life of patients. In addition, it impacts the underlying mechanism and prevention and treatment strategies, indicating that drug selection and efficacy evaluation need to be further investigated. Furthermore, an animal model that is more consistent with the pathological mechanism needs to be developed. In this study, we describe and discuss the methods of developing and detecting CIPNP models in rats and mice induced by cisplatin chemotherapy. The aim was to improve the modeling rate and develop animal models that are more consistent with the developmental pattern of the disease. In addition, the study provides ideal reference animal models for clinical research and drug discovery and development.

Entourage effects of nonpsychotropic cannabinoids on visceral sensitivity in experimental colitis

Abdominal pain is the most disabling symptom of inflammatory bowel diseases, but current treatments are limited, leading patients to seek alternatives such as cannabis. Cannabis contains over 100 cannabinoids which, unlike tetrahydrocannabinol, are biologically active compounds often without psychotropic effects (ie, nonpsychotropic cannabinoids [npCBs]). These npCBs have analgesic and anti-inflammatory properties and may show potentiating effects when administered in combination, referred to as the entourage effect. Here, we investigated the analgesic effects of cannabichromene, cannabidiol (CBD), cannabidivarin, and cannabigerol (CBG), individually and in combination, using the mouse model of dextran sulfate sodium colitis-induced visceral hypersensitivity (VHS). We then explored antinociceptive targets through patch-clamp electrophysiology on dorsal root ganglia neurons and recombinant channels. We found that a single injection of 10 mg/kg of either CBD or CBG reduced both VHS and c-Fos activation in the spinal dorsal horn. Moreover, a combination of npCBs consisting of 5 mg/kg CBD with 1 mg/kg of cannabichromene, cannabidivarin, and CBG-all at subtherapeutic dosages-reduced VHS, without altering colitis. Electrophysiological recordings revealed that the antinociceptive mixture of npCBs acts through voltage-gated sodium and calcium channels, particularly Cav2.2, but not Cav3.2 and Kv channels. These results suggest that CBD, CBG, and a mixture of npCBs given at subtherapeutic doses may be beneficial in managing VHS associated with inflammatory bowel disease. SIGNIFICANCE STATEMENT: Cannabis is increasingly used as an alternative treatment for managing pain associated with chronic conditions. Nonpsychotropic cannabinoids, such as cannabidiol, interact with ionotropic and voltage-gated ion channels. In our study, we demonstrated that cannabidiol, cannabigerol, and a combination of nonpsychotropic cannabinoids, administered at subtherapeutic doses, effectively alleviated visceral hypersensitivity associated with inflammatory bowel disease.

Orally administered Cannabigerol (CBG) in rats: Cannabimimetic actions, anxiety-like behavior, and inflammation-induced pain

Cannabigerol (CBG) is a phytocannabinoid found in cannabis that is promoted for medical use and other health benefits, but current empirical data on the behavioral effects of CBG are lacking. The purpose of this study was to evaluate the effects of a wide dose range of orally administered CBG on outcomes related to its potential cannabimimetic effects (cannabinoid tetrad), as well as effects on anxiety-like behavior, inflammation and related pain hypersensitivity. In a series of experiments, male and female Sprague Dawley rats received oral CBG (per os [p.o.]) or vehicle prior to testing of effects on 1) the cannabinoid tetrad (30-600 mg/kg, p.o.): assessments of locomotor activity, body temperature, antinociception (tail flick test), and catalepsy (bar test); 2) acoustic startle response (ASR) test of anxiety-like behavior (30-300 mg/kg, p.o.); 3) carrageenan-induced inflammation (paw edema), hyperalgesia (Hargreaves test), and allodynia (von Frey test) tests (10-60 mg/kg, p.o.). Positive control groups were administered THC (0-30 mg/kg, p.o.) for the cannabinoid tetrad assay, the benzodiazepine lorazepam (0-3 mg/kg, intraperitoneal [i.p.]) for the ASR test, or the opioid analgesic morphine (0-10 mg/kg, i.p.) for the carrageenan-induced inflammation and pain hypersensitivity tests. CBG did not produce cannabimimetic actions in the tetrad, but increased locomotor activity at the highest doses (300-600 mg/kg). THC produced typical dose-related cannabimimetic effects. CBG did not produce anxiolytic effects in the ASR test, while groups pretreated with lorazepam showed reductions in ASR. Finally, pretreatment with CBG prior to an intraplantar injection of carrageenan did not prevent the induction of an acute inflammatory state (i.e., increased paw edema and associated hyperalgesia and allodynia). In contrast, morphine alleviated hyperalgesia and allodynia induced by intraplantar carrageenan but did not affect the development of paw edema. In sum, these data do not support the use of oral CBG for anxiety or inflammatory pain.

Cannabigerol (CBG): A Comprehensive Review of Its Molecular Mechanisms and Therapeutic Potential

Cannabigerol (CBG), a non-psychoactive cannabinoid found in cannabis, has emerged as a promising therapeutic agent with a diverse range of potential applications. Unlike its well-known counterpart tetrahydrocannabinol (THC), CBG does not induce intoxication, making it an attractive option in the clinic. Recent research has shed light on CBG's intriguing molecular mechanisms, highlighting its potential to modulate multiple physiological processes. This review delves into the current understanding of CBG's molecular interactions and explores its therapeutic power to alleviate various conditions, including cancer, metabolic, pain, and inflammatory disorders, amongst others. We discuss how CBG interacts with the endocannabinoid system and other key signaling pathways, such as CB1, CB2, TPR channels, and α2-adrenoceptor, potentially influencing inflammation, pain, neurodegeneration, and other ailments. Additionally, we highlight the ongoing research efforts aimed at elucidating the full spectrum of CBG's therapeutic potential and its safety profile in clinical settings. Through this comprehensive analysis, we aim to provide a deeper understanding of CBG's role in promoting human health and pave the way for future research endeavors.

Select Minor Cannabinoids from Cannabis sativa Are Cannabimimetic and Antinociceptive in a Mouse Model of Chronic Neuropathic Pain

Chronic pain conditions affect nearly 20% of the population in the United States. Current medical interventions, such as opioid drugs, are effective at relieving pain but are accompanied by many undesirable side effects. This is one reason increased numbers of chronic pain patients have been turning to Cannabis for pain management. Cannabis contains many bioactive chemical compounds; however, current research looking into lesser-studied minor cannabinoids in Cannabis lacks uniformity between experimental groups and/or excludes female mice from investigation. This makes it challenging to draw conclusions between experiments done with different minor cannabinoid compounds between laboratories or parse out potential sex differences that could be present. We chose five minor cannabinoids found in lower quantities within Cannabis: cannabinol (CBN), cannabidivarin (CBDV), cannabigerol (CBG), Δ8-tetrahydrocannabinol (Δ8-THC), and Δ9-tetrahydrocannabivarin (THCV). These compounds were then tested for their cannabimimetic and pain-relieving behaviors in a cannabinoid tetrad assay and a chemotherapy-induced peripheral neuropathy (CIPN) pain model in male and female CD-1 mice. We found that the minor cannabinoids we tested differed in the cannabimimetic behaviors evoked, as well as the extent. We found that CBN, CBG, and high-dose Δ8-THC evoked some tetrad behaviors in both sexes, while THCV and low-dose Δ8-THC exhibited cannabimimetic tetrad behaviors only in females. Only CBN efficaciously relieved CIPN pain, which contrasts with reports from other researchers. Together these findings provide further clarity to the pharmacology of minor cannabinoids and suggest further investigation into their mechanism and therapeutic potential. SIGNIFICANCE STATEMENT: Minor cannabinoids are poorly studied ligands present in lower levels in Cannabis than cannabinoids like THC. In this study, we evaluated five minor cannabinoids (CBN, CBDV, CBG, THCV, and Δ8-THC) for their cannabimimetic and analgesic effects in mice. We found that four of the five minor cannabinoids showed cannabimimetic activity, while one was efficacious in relieving chronic neuropathic pain. This work is important in further evaluating the activity of these drugs, which are seeing wider public use with marijuana legalization.

The Potential of Cannabichromene (CBC) as a Therapeutic Agent

There is a growing interest in the use of medicinal plants to treat a variety of diseases, and one of the most commonly used medicinal plants globally is Cannabis sativa The two most abundant cannabinoids (Δ9-tetrahydrocannabinol and cannabidiol) have been governmentally approved to treat selected medical conditions; however, the plant produces over 100 cannabinoids, including cannabichromene (CBC). Although the cannabinoids share a common precursor molecule, cannabigerol, they are structurally and pharmacologically unique. These differences may engender differing therapeutic potentials. In this review, we will examine what is currently known about CBC with regards to pharmacodynamics, pharmacokinetics, and receptor profile. We will also discuss the therapeutic areas that have been examined for this cannabinoid, notably antinociceptive, antibacterial, and anti-seizure activities. Finally, we will discuss areas where new research is needed and potential novel medicinal applications for CBC. SIGNIFICANCE STATEMENT: Cannabichromene (CBC) has been suggested to have disparate therapeutic benefits such as anti-inflammatory, anticonvulsant, antibacterial, and antinociceptive effects. Most of the focus on the medical benefits of cannabinoids has been focused on Δ9-tetrahydrocannabinol and cannabidiol. The preliminary studies on CBC indicate that this phytocannabinoid may have unique therapeutic potential that warrants further investigation. Following easier access to hemp, CBC products are commercially available over-the-counter and are being widely utilized with little or no evidence of their safety or efficacy.

High Cannabigerol Hemp Extract Moderates Colitis and Modulates the Microbiome in an Inflammatory Bowel Disease Model

Cannabis sativa L. has a long history of medicinal use, particularly for gastrointestinal diseases. Patients with inflammatory bowel disease (IBD) report using cannabis to manage their symptoms, despite little data to support the use of cannabis or cannabis products to treat the disease. In this study, we use the well-described dextran sodium sulfate (DSS) model of colitis in mice to assess the impact of commercially available, noneuphorigenic, high cannabigerol (CBG) hemp extract (20 mg/mL cannabigerol, 20.7 mg/mL cannabidiol, 1 mg/mL cannabichromene) on IBD activity and the colonic microbiome. Mice were given 2% DSS in drinking water for 5 days, followed by 2 days of regular drinking water. Over the 7 days, mice were dosed daily with either high CBG hemp extract or matched vehicle control. Daily treatment with high CBG hemp extract dramatically reduces the severity of disease at the histological and organismal levels as measured by decreased disease activity index, increased colon length, and decreases in percent colon tissue damage. 16S rRNA gene sequencing of the fecal microbiota reveals high CBG hemp extract treatment results in alterations in the microbiota that may be beneficial for colitis. Finally, using metabolomic analysis of fecal pellets, we find that mice treated with high CBG hemp extract have a normalization of several metabolic pathways, including those involved in inflammation. Taken together, these data suggest that high CBG hemp extracts may offer a novel treatment option for patients. SIGNIFICANCE STATEMENT: Using the dextran sodium sulfate model of colitis, the authors show that treatment with high cannabigerol hemp extract reduces the severity of symptoms associated with colitis. Additionally, they show that treatment modulates both the fecal microbiota and metabolome with potential functional significance.

Chemotherapy-Induced Peripheral Neuropathy: A Recent Update on Pathophysiology and Treatment

Chemotherapy-induced peripheral neuropathy (CIPN) is a major long-lasting side effect of some chemotherapy drugs, which threatens cancer survival rate. CIPN mostly affects sensory neurons and occasionally motor neurons, causing numbness, tingling, discomfort, and burning pain in the upper and lower extremities. The pathophysiology of CIPN is not completely understood; however, it is believed that chemotherapies induce peripheral neuropathy via directly damaging mitochondria, impairing the function of ion channels, triggering immunological mechanisms, and disrupting microtubules. The treatment of CIPN is a medical challenge, and there are no approved pharmacological options. Currently, duloxetine and other antidepressants, antioxidant, anti-inflammatory, and ion-channel targeted therapies are commonly used in clinics to relieve the symptoms of CIPN. Several other types of drugs, such as cannabinoids, sigma-1 receptor antagonists, and nicotinamides ribose, are being evaluated in preclinical and clinical studies. This paper summarizes the information related to the physiology of CIPN and medicines that could be used for treating this condition.

Discovery and Preclinical Evaluation of a Novel Inhibitor of FABP5, ART26.12, Effective in Oxaliplatin-Induced Peripheral Neuropathy

Oxaliplatin-induced peripheral neuropathy (OIPN) is a dose-limiting toxicity characterised by mechanical allodynia and thermal hyperalgesia, without any licensed medications. ART26.12 is a fatty acid-binding protein (FABP) 5 inhibitor with antinociceptive properties, characterised here for the prevention and treatment of OIPN. ART26.12 binds selectively to FABP5 compared to FABP3, FABP4, and FABP7, with minimal off-target liabilities, high oral bioavailability, and a NOAEL of 1,000 mg/kg/day in rats and dogs. In an established preclinical OIPN model, acute oral dosing (25-100 mg/kg) showed a cannabinoid receptor type 1 (CB1)-dependent anti-allodynic effect lasting up to 8 hours (persisting longer than plasma exposure to ART26.12). Antagonists of cannabinoid receptor type 2 (CB2), peroxisome proliferator-activated receptor alpha, and transient receptor potential cation channel subfamily V member 1 (TRPV1) may have also been implicated. Twice daily oral dosing (25 mg/kg bis in die (BID) for 7 days) showed anti-allodynic effects in an established OIPN model without the development of tolerance. In a prevention paradigm, coadministration of ART26.12 (10 and 25 mg/kg BID for 15 days) with oxaliplatin prevented thermal hyperalgesia, mitigated mechanical allodynia, and attenuated OXA-induced weight loss. Multi-scale analyses revealed widespread lipid modulation, particularly among N-acyl amino acids in the spinal cord, including potential analgesic mediators. Additionally, ART26.12 administration led to upregulation of ion channels in the periaqueductal grey, and broad translational upregulation within the plasma proteome. These results show promise that ART26.12 is a safe and well-tolerated candidate for the treatment and prevention of OIPN through lipid modulation. PERSPECTIVE: Inhibition of fatty acid-binding protein 5 (FABP5) is a novel target for reducing pain associated with chemotherapy. ART26.12 is a safe and well-tolerated small molecule FABP5 inhibitor effective at preventing and reducing pain induced with oxaliplatin through lipid modulation and activation of cannabinoid receptors.

Phytocannabinoids for the Treatment of Neuropathic Pain: A Scoping Review of Randomised Controlled Trials Published Between 2012 and 2023

PURPOSE OF REVIEW

Neuropathic pain (NP) remains a challenge to treat, with 50% of patients experiencing limited efficacy from current treatments. Medicinal cannabis, which contains tetrahydrocannabinol (THC), cannabidiol (CBD) and other minor cannabinoids, is garnering attention as an alternative treatment for NP. This paper reviews the clinical evidence for phytocannabinoid treatment of NP.

RECENT FINDINGS

Seventeen randomised controlled trials (RCT) were identified for inclusion in this review. Of these, ten studies using phytocannabinoid preparations containing THC alone had the most evidence for pain relief. Four studies investigating THC/CBD combinations showed some reductions in pain scores, although not all findings were statistically significant, whereas studies investigating CBD (two studies) or cannabidivarin (one study) showed no analgesic effect over placebo. However, CBD studies were of small sample size when compared to other studies in the review and short duration. Results for treatment of diabetic peripheral neuropathy patients with THC showed better improvements over those for NP induced by chemotherapy and multiple sclerosis, with these trials using vaporised whole plant cannabis. This formulation may have trace amounts of other minor cannabinoids, compared with synthetic cannabinoids such as dronabinol or nabilone that were investigated in other studies. This review provides an overview of RCTs that have investigated phytocannabinoid use for the treatment of NP. There appears to be evidence to necessitate further high quality RCTs into novel formulations of phytocannabinoids for the treatment of NP.

Non-Intoxicating Cannabinoids in Visceral Pain

Cannabis and cannabis products are becoming increasingly popular options for symptom management of inflammatory bowel diseases, particularly abdominal pain. While anecdotal and patient reports suggest efficacy of these compounds for these conditions, clinical research has shown mixed results. To date, clinical research has focused primarily on delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is a ligand of classical cannabinoid receptors (CBRs). CBD is one of a large group of nonintoxicating cannabinoids (niCBs) that mediate their effects on both CBRs and through non-CBR mechanisms of action. Because they are not psychotropic, there is increasing interest and availability of niCBs. The numerous niCBs show potential to rectify abnormal intestinal motility as well as have anti-inflammatory and analgesic effects. The effects of niCBs are frequently not mediated by CBRs, but rather through actions on other targets, including transient receptor potential channels and voltage-gated ion channels. Additionally, evidence suggests that niCBs can be combined to increase their potency through what is termed the entourage effect. This review examines the pre-clinical data available surrounding these niCBs in treatment of abdominal pain with a focus on non-CBR mechanisms.

Antinociceptive Effects of Cannabichromene (CBC) in Mice: Insights from von Frey, Tail-Flick, Formalin, and Acetone Tests

Cannabis sativa contains minor cannabinoids that have potential therapeutic value in pain management. However, detailed experimental evidence for the antinociceptive effects of many of these minor cannabinoids remains lacking. Here, we employed artificial intelligence (AI) to perform compound-protein interaction estimates with cannabichromene (CBC) and receptors involved in nociceptive signaling. Based on our findings, we investigated the antinociceptive properties of CBC in naïve or neuropathic C57BL/6 male and female mice using von Frey (mechanical allodynia), tail-flick (noxious radiant heat), formalin (acute and persistent inflammatory pain), and acetone (cold thermal) tests. For von Frey assessments, CBC dose (0-20 mg/kg, i.p.) and time (0-6 h) responses were measured in male and female neuropathic mice. For tail-flick, formalin, and acetone assays, CBC (20 mg/kg, i.p.) was administered to naïve male and female mice 1 h prior to testing. The results show that CBC (10 and 20 mg/kg, i.p.) significantly reduced mechanical allodynia in neuropathic male and female mice 1-2 h after treatment. Additionally, CBC treatment caused significant reductions in nociceptive behaviors in the tail-flick assay and in both phase 1 and phase 2 of the formalin test. Finally, we found a significant interaction in neuropathic male mice in the acetone test. In conclusion, our results suggest that CBC targets receptors involved in nociceptive signaling and imparts antinociceptive properties that may benefit males and females afflicted with diverse forms of acute or chronic/persistent pain.

Cannabidiol and Cannabigerol, Nonpsychotropic Cannabinoids, as Analgesics that Effectively Manage Bone Fracture Pain and Promote Healing in Mice

Bone fractures are among the most prevalent musculoskeletal injuries, and pain management is an essential part of fracture treatment. Fractures heal through an early inflammatory phase, followed by repair and remodeling. Nonsteroidal anti-inflammatory drugs (NSAIDs) are not recommended for fracture pain control as they potently inhibit the inflammatory phase and, thus, impair the healing. Opioids do not provide a better alternative for several reasons, including abuse potential. Accordingly, there is an unmet clinical need for analgesics that effectively ameliorate postfracture pain without impeding the healing. Here, we investigated the analgesic efficacy of two nonpsychotropic cannabinoids, cannabidiol (CBD) and cannabigerol (CBG), in a mouse model for tibial fracture. Mice with fractured tibiae exhibited increased sensitivity to mechanical, cold, and hot stimuli. Both CBD and CBG normalized pain sensitivity to all tested stimuli, and their analgesic effects were comparable to those of the NSAIDs. Interestingly, CBD and CBG promoted bone healing via multiple mechanisms during the early and late phases. During the early inflammatory phase, both cannabinoids increased the abundance of periosteal bone progenitors in the healing hematoma and promoted the osteogenic commitment of these progenitors. During the later phases of healing, CBD and CBG accelerated the fibrocartilaginous callus mineralization and enhanced the viability and proliferation of bone and bone-marrow cells. These effects culminated in higher bone volume fraction, higher bone mineral density, and improved mechanical quality of the newly formed bone. Together, our data suggest CBD and CBG as therapeutic agents that can replace NSAIDs in managing postfracture pain as both cannabinoids exert potent analgesic effects and, at the same time, promote bone healing. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Chronic Cannabigerol as an Effective Therapeutic for Cisplatin-Induced Neuropathic Pain

Cannabigerol (CBG), derived from the cannabis plant, acts as an acute analgesic in a model of cisplatin-induced peripheral neuropathy (CIPN) in mice. There are no curative, long-lasting treatments for CIPN available to humans. We investigated the ability of chronic CBG to alleviate mechanical hypersensitivity due to CIPN in mice by measuring responses to 7 and 14 days of daily CBG. We found that CBG treatment (i.p.) for 7 and 14 consecutive days significantly reduced mechanical hypersensitivity in male and female mice with CIPN and reduced pain sensitivity up to 60-70% of baseline levels (p < 0.001 for all), 24 h after the last injection. Additionally, we found that daily treatment with CBG did not evoke tolerance and did not incur significant weight change or adverse events. The efficacy of CBG was independent of the estrous cycle phase. Therefore, chronic CBG administration can provide at least 24 h of antinociceptive effect in mice. These findings support the study of CBG as a long-lasting neuropathic pain therapy, which acts without tolerance in both males and females.

The antinociceptive activity and mechanism of action of cannabigerol

Cannabis has been used for centuries to treat pain. The antinociceptive activity of tetrahydrocannabinol (THC) or cannabidiol (CBD) has been widely studied. However, the antinociceptive effects of other cannabis components, such as cannabichromene (CBC) and cannabigerol (CBG), have rarely been revealed. The antinociceptive mechanism of CBG is not yet clear, so we investigated the antinociceptive effect of CBG on different pain models, and explored the mechanism of action of CBG to exert antinociceptive effects. In the current study, we compared the antinociceptive effects of CBC, CBD, and CBG on the carrageenan-induced inflammatory pain model in mice, and the results showed that CBG had a better antinociceptive effects through intraplantar administration. On this basis, we further investigated the antinociceptive effect of CBG on CIA-induced arthritis pain model and nerve pain model in mice, and found that CBG also relieved on both types of pain. Then, we explored the antinociceptive mechanism of CBG, which revealed that CBG can activate TRPV1 and desensitize it to block the transmission of pain signals. In addition, CBG can further activate CB2R, but not CB1R, to stimulate the release of β-endorphin, which greatly promotes the antinociceptive effect. Finally, the safety test results showed that CBG had no irritating effect on the rabbits' skin, and it did not induce significant biochemical and hematological changes in mice. Transdermal delivery results also indicated that CBG has certain transdermal properties. Overall, this study indicates that CBG is promising for developing a transdermal dosage for pain management.

Efficient Synthesis for Altering Side Chain Length on Cannabinoid Molecules and Their Effects in Chemotherapy and Chemotherapeutic Induced Neuropathic Pain

(1) Background: Recently, a number of side chain length variants for tetrahydrocannabinol and cannabidiol have been identified in cannabis; however, the precursor to these molecules would be based upon cannabigerol (CBG). Because CBG, and its side chain variants, are rapidly converted to other cannabinoids in the plant, there are typically only small amounts in plant extracts, thus prohibiting investigations related to CBG and CBG variant therapeutic effects. (2) Methods: To overcome this, we developed an efficient synthesis of corresponding resorcinol fragments using the Wittig reaction which, under acid catalyzed coupling with geraniol, produced the desired side chain variants of CBG. These compounds were then tested in an animal model of chemotherapeutic-induced neuropathic pain and to reduce colorectal cancer cell viability. (3) Results: We found that all side-chain variants were similarly capable of reducing neuropathic pain in mice at a dose of 10 mg/kg. However, the molecules with shorter side chains (i.e., CBGV and CBGB) were better at reducing colorectal cancer cell viability. (4) Conclusions: The novel synthesis method developed here will be of utility for studying other side chain derivatives of minor cannabinoids such as cannabichromene, cannabinol, and cannabielsoin.

Secondary Terpenes in Cannabis sativa L.: Synthesis and Synergy

Cannabis is a complex biosynthetic plant, with a long history of medicinal use. While cannabinoids have received the majority of the attention for their psychoactive and pharmacological activities, cannabis produces a diverse array of phytochemicals, such as terpenes. These compounds are known to play a role in the aroma and flavor of cannabis but are potent biologically active molecules that exert effects on infectious as well as chronic diseases. Furthermore, terpenes have the potential to play important roles, such as synergistic and/or entourage compounds that modulate the activity of the cannabinoids. This review highlights the diversity and bioactivities of terpenes in cannabis, especially minor or secondary terpenes that are less concentrated in cannabis on a by-mass basis. We also explore the question of the entourage effect in cannabis, which studies to date have supported or refuted the concept of synergy in cannabis, and where synergy experimentation is headed, to better understand the interplay between phytochemicals within Cannabis sativa L.

Combinations of Cannabidiol and Δ9-Tetrahydrocannabinol in Reducing Chemotherapeutic Induced Neuropathic Pain

Neuropathic pain is a condition that impacts a substantial portion of the population and is expected to affect a larger percentage in the future. This type of pain is poorly managed by current therapies, including opioids and NSAIDS, and novel approaches are needed. We used a cisplatin-induced model of neuropathic pain in mice to assess the effects of the cannabinoids THC and CBD alone or in varying ratios as anti-nociceptive agents. In addition to testing pure compounds, we also tested extracts containing high THC or CBD at the same ratios. We found that pure CBD had little impact on mechanical hypersensitivity, whereas THC reduced mechanical hypersensitivity in both male and female mice (as has been reported in the literature). Interestingly, we found that high CBD cannabis extract, at the same CBD dose as pure CBD, was able to reduce mechanical hypersensitivity, although not to the same level as high THC extract. These data suggest that, at least for CBD-dominant cannabis extracts, there is an increase in the anti-nociceptive activity that may be attributed to other constitutes of the plant. We also found that high THC extract or pure THC is the most efficacious treatment for reducing neuropathic pain in this model.