Axially Chiral Cannabinoids: Design, Synthesis, and Cannabinoid Receptor Affinity

Chiral recognition of CIAC001 isomers in regulating pyruvate kinase M2 and mitigating neuroinflammation

Chiral recognition plays a critical role in drug efficacy within biological systems. CIAC001, a cannabidiol (CBD) derivative that targets pyruvate kinase M2 (PKM2), has shown strong anti-neuroinflammatory and anti-morphine addiction effects. However, the chiral recognition of CIAC001, which contains multiple chiral centers, remains poorly understood. In this study, four chiral isomers of CIAC001 were synthesized, revealing distinct chiral recognition patterns for PKM2. Notably, (7S)-(-)-CIAC001 exhibited superior anti-neuroinflammation activity, with a significantly stronger binding affinity and a lower dissociation constant (2.2 μM) compared to its (7R)-(-) counterpart. Molecular dynamics simulations revealed that (7S)-(-)-CIAC001 forms π-π stacking interactions with phenylalanine at position 26 (F26) on two PKM2 subunits, contributing to its stronger binding energy. Substitution of F26 with alanine abolished the binding of (7S)-(-)-CIAC001, underscoring the importance of this residue. In in vivo assays, (7S)-(-)-CIAC001 more effectively inhibited IL-1β transcription, demonstrating greater anti-neuroinflammatory and anti-morphine addiction activity. This study highlights the differential chiral recognition of CIAC001 isomers by PKM2, with F26 identified as a key residue, providing valuable insights for the future development of chiral cannabinoid therapeutics.

Ligand-Governed Regio- and Enantioselective [2 + 2 + 2] Cycloaddition of 1,7-Enynes: Assembly of the Benzo[c]chromen-1-ol Backbone and Access to Enantioenriched Cannabinol Bioisostere

We herein report a regioselective synthesis of the benzo[c]chromenol core via cationic rhodium-catalyzed [2 + 2 + 2] cycloaddition of 1,7-enynes with tetrolic acid derivatives. With the selection of an appropriate ligand, both regioisomers could be obtained in excellent regiomeric ratio and enantiomeric excess. The regioselectivity was governed by different factors, which was suggested by computational studies. Furthermore, the asymmetric synthesis of an axially chiral cannabinol bioisostere candidate was achieved by the transformation from central chirality to axial chirality. Demonstration of the synthesis of a natural compound was also depicted.

Stereoisomers of cannabidiols and their pharmacological activities - A potentially novel direction for cannabinoids

Cannabidiol (CBD), a bicyclic non-psychoactive cannabinoid biosynthesized by Cannabis spp. of plants, has attracted significant interest in the past decade due to its therapeutic properties. In 2018, the US FDA approved Epidiolex®, a CBD-based drug for the treatment of two rare epileptic seizure disorders. CBD possesses two chiral centers at C3 and C4 on its terpenoid moiety and exhibits cis-trans stereoisomerism along the C3-C4 bond axis. (-)-trans-(3R,4R)-CBD, the natural CBD, is biosynthesized by the cannabis plant, while the unnatural (+)-trans-(3S,4S)-CBD is obtained via chemical synthesis. Both trans isomers exhibit broad in vitro and in vivo biological activities; typically, the unnatural stereoisomer (+)-trans-CBD and its derivatives exhibited more potent activities in comparison to the corresponding (-)-trans isomers. On the other hand, cis-CBD isomers have only been reported recently and can undergo epimerization into trans isomers. There is a significant opportunity to explore unique synthetic methods and biological activities of stereoisomers of CBD that may pave the path for the development of novel therapeutics. Herein, as a novel direction in cannabinoids, we review the chemistry of CBD stereoisomers, their structure-activity relationships, target selectivity and efficacy in animal models.

Synthesis of (-)-Cannabidiol (CBD), (-)-Δ9- and (-)-Δ8-Tetrahydrocannabinols, Encapsulation of CBD with Nanoparticles for Controlled Delivery and Biological Evaluation

Cannabidiol (CBD) is garnering increasing interest due to its significant biological activity. This natural compound is one of the major cannabinoids in Cannabis sativa L. In this work, we describe the encapsulation of CBD in solid and hollow pH-sensitive poly(4-vinylpyridine) (solid@p4VP and hollow@p4VP) nanoparticles, and temperature-sensitive poly(N-isopropylacrylamide) (solid@pNIPAM and hollow@pNIPAM) nanoparticles for transport and release CBD in a controlled manner. The CBD loading into these smart polymeric systems was effective and their release profiles, solubility and resistance to stomach and intestinal conditions were evaluated, showing satisfactory properties and improved bioavailability with respect to free CBD. Finally, the A549 human lung cancer cell line was used as lung adenocarcinoma epithelial cellular model to carry out preliminary assays of the in vitro activity of the vehiculized CBD. For all these studies, synthetic CBD was employed, for which a new efficient and scalable synthesis of cannabinoids has been developed.

Cannabinoids as a Natural Alternative for the Management of Neuropathic Pain: A Systematic Review of Randomized Placebo-Controlled Trials

Dysfunction or damage to the nervous system may develop into and result in a chronic pain condition known as neuropathic pain. Neuropathic pain is defined as the structural and functional alteration of the somatosensory component of the nervous system. The treatment of neuropathic pain is a complex endeavor, which often requires specialist care and intensive drug therapy. Recently, cannabinoids have emerged as an alternative and natural option for the treatment of chronic pain, with tetrahydrocannabinol (THC) and cannabidiol (CBD) being the most extensively studied neuroactive components. The therapeutic potential of cannabis remains largely underexplored, primarily due to its social stigma and the restrictions that are in place on its cultivation. The primary aim of this systematic review was to explore the therapeutic value of cannabinoids in the management of chronic pain and thus achieve an improved quality of life for those patients. A systematic review of the literature published over the last two decades was performed using the following databases: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Turning research into practice (Trip), and Google Scholar. Studies that were completed and published between January 01, 2000 and August 31, 2024, in English language, were extracted and appraised. A combination of keywords and Boolean operators Cannabis OR Chronic Pain OR End of life OR Pain Management AND Drug therapy was employed for data extraction. The Cochrane risk-of-bias tool for randomized trials (RoB 2) was used for risk-of-bias assessment. The initial search resulted in 125282 articles; 86,781 of the articles were identified as duplicates and were removed from the primary analysis, and 38,501 abstracts were thus screened. Abstracts, case studies, reports, editorials, viewpoints, cross-sectional studies, cohort studies, case-control studies, case series, and letters to the editor/correspondence manuscripts (n =38,492) were furthermore excluded. Nine full-text articles were critically assessed and tested against the inclusion and exclusion criteria, and a further four articles were excluded with a total of five placebo-controlled randomized control studies being ultimately included in the final systematic review. Compared to placebo, cannabinoids provided significant relief from chronic pain (33% vs 15%) as measured by the visual analog scale. The transdermal application of CBD led to a more pronounced reduction in sharp pain, according to the neuropathic pain scale. Minimal to no side effects were recorded, further highlighting the potential benefits of cannabinoids.

Evaluation of cannabimimetic effects of selected minor cannabinoids and Terpenoids in mice

BACKGROUND

The cannabis plant contains several cannabinoids, and many terpenoids that give cannabis its distinctive flavoring and aroma. Δ9-Tetrahydrocannabinol (Δ9-THC) is the plant's primary psychoactive constituent. Given the abuse liability of Δ9-THC, assessment of the psychoactive effects of minor cannabinoids and other plant constituents is important, especially for compounds that may be used medicinally. This study sought to evaluate select minor cannabinoids and terpenes for Δ9-THC-like psychoactivity in mouse Δ9-THC drug discrimination and determine their binding affinities at CB1 and CB2 receptors.

METHODS

Δ9-THC, cannabidiol (CBD), cannabinol (CBN), cannabichromene (CBC), cannabichromenevarin (CBCV), Δ8-tetrahydrocannabinol (Δ8-THC), (6aR,9R)-Δ10-tetrahydrocannabinol [(6aR,9R)-Δ10-THC], Δ9-tetrahydrocannabinol varin (THCV), β-caryophyllene (BC), and β-caryophyllene oxide (BCO) were examined.

RESULTS

All minor cannabinoids showed measurable cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptor binding, with CBC, CBCV, and CBD, showing the weakest CB1 receptor binding affinity. BC and BCO exhibited negligible affinity for both CB1 and CB2 receptors. In drug discrimination, only Δ8-THC fully substituted for Δ9-THC, while CBN and (6aR,9R)-Δ10-THC partially substituted for Δ9-THC. THCV and BCO did not alter the discriminative stimulus effects of Δ9-THC.

CONCLUSION

In summary, only some of myriad cannabinoids and other chemicals found in the cannabis plant bind potently to the identified cannabinoid receptors. Further, only four of the compounds tested herein [Δ9-THC, Δ8-THC, (6aR,9R)-Δ10-THC, and CBN] produced Δ9-THC-like discriminative stimulus effects, suggesting they may possess cannabimimetic subjective effects. Given that the medicinal properties of phytocannabinoids and terpenoids are being investigated scientifically, delineation of their potential adverse effects, including their ability to produce Δ9-THC-like intoxication, is crucial.

Enantiomeric analysis of chiral phenyl aromatic compounds by coated capillary electrochromatography based on a MOF-on-MOF stationary phase

Chiral phenyl aromatic compounds (CPACs) are widely used in drug development, food/cosmetic production, and other organic synthesis processes, and their different enantiomers have distinct physiological activities and application differences. A double-layer metal-organic framework composite (MOF-on-MOF) was obtained by in situ synthesis of chiral metal-organic framework (CMOM-3S) on the surface of an iron-based metal-organic framework (NH2-MIL-101(Fe)). According to our investigation, MOF-on-MOF composite was for the first time applied to the stationary phase of capillary electrochromatography (CEC), and enantioseparations of eight CPACs were accomplished. Compared with single CMOM-3S, the enantioseparation performance of the coated capillary columns based on NH2-MIL-101(Fe)@CMOM-3S was improved by 34.07 ~ 720.0%. The R-/S-mandelic acid in actual sample (apricot leaves) was detected by the newly CEC system to be 0.0118 mg mL-1 and 0.0523 mg mL-1, respectively. The spike recoveries were 96.60 ~ 104.7%, indicating its good stability and accuracy. In addition, the selective adsorption capacity of MOF-on-MOF composites was verified by adsorption experiments.

NHC-Catalyzed Chemo- and Enantioselective Reaction between Aldehydes and Enals for Access to Axially Chiral Arylaldehydes

A chiral carbene-catalyzed chemo- and enantioselective reaction with racemic biaryl aldehydes and α-bromoenals is developed for access to axially chiral 2-arylbenzaldehydes through atroposelective dynamic kinetic resolution (DKR) processes. This atroposelective DKR strategy can tolerate a broad scope of substrates with diverse functionalities. The axially chiral 2-aryl benzaldehyde products generally afford moderate to good yields and enantioselectivities. The axially chiral molecules afforded from the current approach are variable through simple transformations to afford axially chiral functional molecules with excellent optical purities.

Catalytic Atroposelective Synthesis of Axially Chiral Azomethine Imines and Neuroprotective Activity Evaluation

Azomethine imines, as a prominent class of 1,3-dipolar species, hold great significance and potential in organic and medicinal chemistry. However, the reported synthesis of centrally chiral azomethine imines relies on kinetic resolution, and the construction of axially chiral azomethine imines remains unexplored. Herein, we present the synthesis of axially chiral azomethine imines through copper- or chiral phosphoric acid catalyzed ring-closure reactions of N'-(2-alkynylbenzylidene)hydrazides, showcasing high efficiency, mild conditions, broad substrate scope, and excellent enantioselectivity. Furthermore, the biological evaluation revealed that the synthesized axially chiral azomethine imines effectively protect dorsal root ganglia (DRG) neurons by inhibiting apoptosis induced by oxaliplatin, offering a promising therapeutic approach for chemotherapy-induced peripheral neuropathy (CIPN). Remarkably, the (S)- and (R)-atropisomers displayed distinct neuroprotective activities, underscoring the significance of axial stereochemistry.

Atropisomerism about aryl-C(sp3) bonds: chemically driven rotational pathway in cannabidiol derivatives

The conformational behaviour arising from the restricted C(sp2)-C(sp3) axis in ortho O-substituted naphthylcyclohexane and naphthylcyclohexene oxide derivatives of cannabidiol was examined by means of VT-NMR experiments and DFT calculations. Atropisomeric compounds with barriers in the range of 91.1 to 95.1 kJ mol-1 were obtained at 298 K. Two possible transition states (TS1 and TS2) were located, one is more stable depending on the chemical modification made on the monoterpene ring close to the pivot bond. Extended analysis of TS structures to previously reported phenyl derivatives bearing the same O-substituent led to similar rotational pathways according to the series: through TS1 in arylcylohexenes and TS2 in arylcyclohexanes. Likewise, conversion of arylcyclohexenes into both series affects the rotation speed by decelerating it, and the nature of the aryl ring seems to have a very minor effect on this phenomenon.

Synthesis of Neocannabinoids Using Controlled Friedel-Crafts Reactions

A one-step transformation to produce 8,9-dihydrocannabidiol (H2CBD) and related "neocannabinoids" via controlled Friedel-Crafts reactions is reported. Experimental and computational studies probing the mechanism of neocannabinoid synthesis from cyclic allylic alcohol and substituted resorcinol reaction partners provide understanding of the kinetic and thermodynamic factors driving regioselectivity for the reaction. Herein, we present the reaction scope for neocannabinoid synthesis including the production of both normal and abnormal isomers under both kinetic and thermodynamic control. Discovery and optimization of this one-step protocol between various allylic alcohols and resorcinol derivatives are discussed and supported with density functional theory calculations.

Therapeutic Potential of Minor Cannabinoids in Dermatological Diseases-A Synthetic Review

Dermatological diseases pose a significant burden on the quality of life of individuals and can be challenging to treat effectively. In this aspect, cannabinoids are gaining increasing importance due to their therapeutic potential in various disease entities including skin diseases. In this synthetic review, we comprehensively analyzed the existing literature in the field of potential dermatological applications of a lesser-known subgroup of cannabinoids, the so-called minor cannabinoids, such as cannabidivarin (CBDV), cannabidiforol (CBDP), cannabichromene (CBC), tetrahydrocannabivarin (THCV), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabielsoin (CBE), cannabimovone (CBM) or cannabinol (CBN), while drawing attention to their unique pharmacological properties. We systematically searched the available databases for relevant studies and analyzed the data to provide an overview of current thematic knowledge. We looked through the full-text, bibliographic and factographic databases, especially Scopus, Web of Science, PubMed, Polish Scientific Journals Database, and selected the most relevant papers. Our review highlights that minor cannabinoids exhibit diverse pharmacological activities, including anti-inflammatory, analgesic, antimicrobial, and anti-itch properties. Several studies have reported their efficacy in mitigating symptoms associated with dermatological diseases such as psoriasis, eczema, acne, and pruritus. Furthermore, minor cannabinoids have shown potential in regulating sebum production, a crucial factor in acne pathogenesis. The findings of this review suggest that minor cannabinoids hold therapeutic promise in the management of dermatological diseases. Further preclinical and clinical investigations are warranted to elucidate their mechanisms of action, determine optimal dosage regimens, and assess long-term safety profiles. Incorporating minor cannabinoids into dermatological therapies could potentially offer novel treatment options of patients and improve their overall well-being.