Iodine-mediated cyclization of cannabigerol (CBG) expands the cannabinoid biological and chemical space

Phytochemical Characterization and TRPA1/TRPM8 Modulation Profile of the Cannabigerol-Rich Cannabis sativa L. Chemotype IV

The first detailed phytochemical analysis of the cannabigerol (CBG)-rich chemotype IV of Cannabis sativa L. resulted in the isolation of the expected cannabigerolic acid/cannabigerol (CBGA/CBG) and cannabidiolic acid/cannabidiol (CBDA/CBD) and of nine new phytocannabinoids (5-13), which were fully characterized by HR-ESIMS and 1D and 2D NMR. These included mono- or dihydroxylated CBGA/CBG analogues, a congener with a truncated side chain (10), cyclocannabigerol B (11), and the CBD derivatives named cannabifuranols (12 and 13). Cyclocannabigerol B and cannabifuranols are characterized by a novel phytocannabinoid structural architecture. The isolated phytocannabinoids were assayed on the receptor channels TRPA1 and TRPM8, unveiling a potent dual TRPA1 agonist/TRPM8 antagonist profile for compounds 6, 7, and 14. Chiral separation of the two enantiomers of 5 resulted in the discovery of a synergistic effect of the two enantiomers on TRPA1.

Biosynthesis of cannabigerol and cannabigerolic acid: the gateways to further cannabinoid production

Cannabinoids are a therapeutically valuable class of secondary metabolites with a vast number of substituents. The native cannabinoid biosynthetic pathway of Cannabis sativa generates cannabigerolic acid (CBGA), the common substrate to multiple cannabinoid synthases. The bioactive decarboxylated analog of this compound, cannabigerol (CBG), represents an alternate gateway into the cannabinoid space as a substrate either to non-canonical cannabinoid synthase homologs or to synthetic chemical reactions. Herein, we describe the identification and repurposing of aromatic prenyltransferase (AtaPT), which when coupled with native enzymes of C. sativa can form an Escherichia coli production system for CBGA in cell lysates and CBG in whole cells. Engineering of AtaPT, guided by structural analysis, was performed to enhance its kinetics toward CBGA production for subsequent use in a proof-of-concept lysate system. For the first time, we show a synthetic biology platform for CBG biosynthesis in E. coli cells by employing AtaPT under an optimized microbial system. Our results have therefore set the foundation for sustainable production of well-researched and rarer cannabinoids in an E. coli chassis. Graphical Abstract.

A Classic Photochemical Approach Inducing an Unexpected Rearrangement: Exploring the Photoreactivity of Pentacyclic Triterpenic Acids

The discovery of new bioactivities is closely related to the generation of novel scaffolds, and in the past few years different strategies have been proposed to obtain unknown architectures from the manipulation of known compounds. In the present study, we exploited a vintage photochemical approach for the discovery of an unexpected pathway of reactivity related to Δ¹-3-oxo-pentacyclic triterpenic acids gaining access to a new class of natural-unnatural 5(10→1)abeo-pentacyclic triterpenic acids.

Cannabinol: History, Syntheses, and Biological Profile of the Greatest "Minor" Cannabinoid

Cannabis (Cannabis sativa L.) is an outstanding source of bioactive natural products, with more than 150 different phytocannabinoids isolated throughout the decades; however, studies of their bioactivity have historically concentrated on the so-called "big four" [∆⁹-THC (1a), CBD (2a), CBG (3a) and CBC (4a)]. Among the remaining products, which have traditionally been referred to as "minor cannabinoids", cannabinol (CBN, 5a) stands out for its important repercussions and implications on the global scientific landscape. Throughout this review, we will describe why CBN (5a) deserves a prominent place within the so-called "cannabinome", providing an overview on its history, the syntheses developed, and its bioactivity, highlighting its promising pharmacological potential and the significant impact that the study of its chemistry had on the development of new synthetic methodologies.

Major Phytocannabinoids and Their Related Compounds: Should We Only Search for Drugs That Act on Cannabinoid Receptors?

The most important discoveries in pharmacology, such as certain classes of analgesics or chemotherapeutics, started from natural extracts which have been found to have effects in traditional medicine. Cannabis, traditionally used in Asia for the treatment of pain, nausea, spasms, sleep, depression, and low appetite, is still a good candidate for the development of new compounds. If initially all attention was directed to the endocannabinoid system, recent studies suggest that many of the clinically proven effects are based on an intrinsic chain of mechanisms that do not necessarily involve only cannabinoid receptors. Recent research has shown that major phytocannabinoids and their derivatives also interact with non-cannabinoid receptors such as vanilloid receptor 1, transient receptor ankyrin 1 potential, peroxisome proliferator-activated receptor-gamma or glitazone receptor, G55 protein-coupled receptor, and nuclear receptor, producing pharmacological effects in diseases such as Alzheimer's, epilepsy, depression, neuropathic pain, cancer, and diabetes. Nonetheless, further studies are needed to elucidate the precise mechanisms of these compounds. Structure modulation of phytocannabinoids, in order to improve pharmacological effects, should not be limited to the exploration of cannabinoid receptors, and it should target other courses of action discovered through recent research.

Pharmacological potential of varinic-, minor-, and acidic phytocannabinoids

While natural Δ9-tetrahidrocannabinol (Δ9THC), cannabidiol (CBD), and their therapeutic potential have been extensively researched, some cannabinoids have been less extensively investigated. The present article compiles data from the literature that highlight the health benefits and therapeutic potential of lesser known phytocannabinoids, which we have divided into varinic, acidic, and "minor" (i.e., cannabinoids that are not present in high quantities in common varieties of Cannabis sativa L). A growing interest in these compounds, which are enriched in some cannabis varieties, has already resulted in enough preclinical information to show that they are promising therapeutic agents for a variety of diseases. Every phytocannabinoid has a "preferential" mechanism of action, and often targets the cannabinoid receptors, CB1 and/or CB2. The recent resolution of the structure of cannabinoid receptors demonstrates the atypical nature of cannabinoid binding, and that different binding modes depend on the agonist or partial agonist/inverse agonist, which allows for differential signaling, even acting on the same cannabinoid receptor. In addition, other players and multiple signaling pathways may be targeted/engaged by phytocannabinoids, thereby expanding the mechanistic possibilities for therapeutic use.

Mammalian Transient Receptor Potential TRPA1 Channels: From Structure to Disease

The transient receptor potential ankyrin (TRPA) channels are Ca²⁺-permeable nonselective cation channels remarkably conserved through the animal kingdom. Mammals have only one member, TRPA1, which is widely expressed in sensory neurons and in non-neuronal cells (such as epithelial cells and hair cells). TRPA1 owes its name to the presence of 14 ankyrin repeats located in the NH₂ terminus of the channel, an unusual structural feature that may be relevant to its interactions with intracellular components. TRPA1 is primarily involved in the detection of an extremely wide variety of exogenous stimuli that may produce cellular damage. This includes a plethora of electrophilic compounds that interact with nucleophilic amino acid residues in the channel and many other chemically unrelated compounds whose only common feature seems to be their ability to partition in the plasma membrane. TRPA1 has been reported to be activated by cold, heat, and mechanical stimuli, and its function is modulated by multiple factors, including Ca²⁺, trace metals, pH, and reactive oxygen, nitrogen, and carbonyl species. TRPA1 is involved in acute and chronic pain as well as inflammation, plays key roles in the pathophysiology of nearly all organ systems, and is an attractive target for the treatment of related diseases. Here we review the current knowledge about the mammalian TRPA1 channel, linking its unique structure, widely tuned sensory properties, and complex regulation to its roles in multiple pathophysiological conditions.

One-Pot Total Synthesis of Cannabinol via Iodine-Mediated Deconstructive Annulation

The thermal degradation of cannabichromene (CBC, 3) is dominated by cationic reactions and not by the pericyclic rearrangements observed in model compounds. The rationalization of these differences inspired the development of a process that coupled, in an aromatization-driven single operational step, the condensation of citral and alkylresorciniols to homoprenylchromenes and their in situ deconstructive annulation to benzo[c]chromenes. This process was applied to a total synthesis of cannabinol (CBN, 5) and to its molecular editing.

Chemical constituents of the trunks and roots of Thuja sutchuenensis

Five new compounds including two stilbenes, designated thujasutchins A (1) and B (2), two phenolic compounds namely thujasutchins C (3) and D (4), as well as one sesquiterpene thujasutchin E (5), were isolated from the 95% ethanolic extract from the trunks and roots of Thuja sutchuenensis. Their structures were determined by means of extensively spectroscopic analysis including UV, IR, HRESIMS, ¹H and ¹³C NMR (COSY, HSQC, HMBC). Moreover, compounds 1, 3-5 were evaluated for in vitro cytotoxic activities against SF-268, MCF-7, HepG-2, and A549 tumor cell lines.