Analysis of impurities of cannabidiol from hemp. Isolation, characterization and synthesis of cannabidibutol, the novel cannabidiol butyl analog

Analysis of phytocannabinoids in hemp seeds, sprouts and microgreens

Hemp-sprouts are emerging as a new class of attractive functional food due to their numerous health benefits when compared to other sprout species. Indeed, the high content of beneficial components including polyphenols and flavonoids makes this type of food a promising and successful market. However, the available literature on this topic is limited and often conflicting as regards to the content of phytocannabinoids. High-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC-HRMS) was applied in an untargeted metabolomics fashion to extracts of hemp seeds, sprouts and microgreens of nine different genotypes. Both unsupervised and supervised multivariate statistical analysis was performed to reveal variety-specific profiles of phytocannabinoids with surprisingly remarkable levels of phytocannabinoids even in chemotype V samples. Furthermore, a targeted HPLC-HRMS analysis was carried out for the quantitative determination of the major phytocannabinoids including CBDA, CBD, CBGA, CBG, CBCA, CBC, THCA, and trans-Δ9-THC. The last part of the study was focused on the evaluation of the enantiomeric composition of CBCA in hemp seeds, sprouts and microgreens in the different varieties by HPLC-CD (HPLC with online circular dichroism). Chiral analysis of CBCA showed a wide variability of its enantiomeric composition in the different varieties, thus contributing to the understanding of the intriguing stereochemical behavior of this compound in an early growth stage. However, further investigation is needed to determine the genetic factors responsible for the low enantiopurity of this compound.

A new HPLC method with multiple detection systems for impurity analysis and discrimination of natural versus synthetic cannabidiol

Cannabidiol (CBD) is the main non-psychoactive phytocannabinoid derived from Cannabis sativa L. It is now an active pharmaceutical ingredient (API), given its usage in treating some types of pediatric epilepsy. For this reason, this compound requires a deep characterization in terms of purity and origin. Previous research work has shown two impurities in CBD samples from hemp inflorescences, namely, cannabidivarin (CBDV) and cannabidibutol (CBDB), while abnormal-cannabidiol (abn-CBD) has been described as the primary by-product that is generated from CBD synthesis. Both natural and synthetic CBD samples exhibit the presence of Δ9-tetrahydrocannabinol (Δ9-THC) and Δ8-THC. This study aimed to develop a new analytical method based on high-performance liquid chromatography (HPLC) with different detection systems to study the purity of CBD and to define its origin based on the impurity profile. In addition to the above-mentioned cannabinoids, other compounds, such as cannabigerovarin (CBGV), cannabigerol (CBG), cannabichromevarin (CBCV), and cannabichromene (CBC), were examined as potential discriminating impurities. Qualitative and quantitative analyses were carried out by UHPLC-HRMS and HPLC-UV/Vis, respectively. Principal component analysis was applied for statistical exploration. Natural CBD samples exhibited purities ranging between 97.5 and 99.7%, while synthetic samples were generally pure, except for three initially labeled as synthetic, revealing natural-derived impurities. To further confirm the origin of CBD samples, the presence of other two minor impurities, namely cannabidihexol (CBDH) and cannabidiphorol (CBDP), was assessed as unequivocal for a natural origin. Finally, an enantioselective HPLC analysis was carried out and the results confirmed the presence of the (-)-trans enantiomer in all CBD samples. In conclusion, the HPLC method developed represents a reliable tool for detecting CBD impurities, thus providing a clear discrimination of the compound origin.

Comprehensive cannabinoid profiling of acid-treated CBD samples and Δ8-THC-infused edibles

Δ8-Tetrahydrocannabinol (Δ8-THC) is increasingly popular as a controversial substitute for Δ9-tetrahydrocannabinol (Δ9-THC) in cannabinoid-infused edibles. Δ8-THC is prepared from cannabidiol (CBD) by treatment with acids. Side products including Δ9-THC and other isomers that might end up in Δ8-THC edibles are less studied. In this paper, three orthogonal methods, namely reversed-phase (RP)-UHPLC-DAD/HRMS, normal-phase/argentation (silica-Ag(I))-HPLC-DAD/MS, and GC-FID/MS were developed for analysis of cannabinoid isomers, namely Δ8-THC, Δ9-THC, CBD, Δ8-iso-THC, Δ(4)8-iso-THC, and hydrated THC isomers. Eight acid-treated CBD mixtures contained various amounts of Δ8-THC (0-89%, w/w%), high levels of Δ9-THC (up to 49%), Δ8-isoTHC (up to 55%), Δ(4)8-iso-THC (up to 17%), and three hydrated THC isomers. Commercial Δ8-THC gummies were also analyzed, and issues like overclaimed Δ8-THC, excessive Δ9-THC, undeclared Δ8-iso-THC, and Δ(4)8-iso-THC were found. These findings highlight the urgency of improving regulations towards converting CBD to Δ8-THC for use as food ingredients.

Uncovering the metabolite complexity and variability of cultivated hemp (Cannabis sativa L.): A first phytochemical diversity mapping in Greece

The high value of fiber-type Cannabis sativa L. (hemp) due to its phytochemicals has yet to be fully recognized and leveraged. Besides cannabidiol (CBD), which is the most prevalent non-psychoactive cannabinoid, hemp contains numerous other cannabinoids with unexplored bioactivities, in addition to various compound classes. Previous works have aimed to correlate chemical profiles of C. sativa inflorescences with important parameters, mostly based on experiments under controlled conditions. However, mapping studies that explore the phytochemical diversity of hemp in a more realistic context are crucial to guide decisions at multiple levels, especially in areas where hemp cultivation was recently re-authorized, including Mediterranean countries. In this work, a powerful strategy was followed to map the phytochemical diversity of cultivated hemp in Greece, being the first study of its kind for this environment. A panel of 98 inflorescence samples, covering two harvesting years, eleven geographical regions and seven commonly used EU varieties, were studied using a combination of targeted and untargeted approaches. Quantitative results based on UPLC-PDA revealed relatively constant CBD/THC (total) ratios, while profiling by LC-HRMS effectively probed the phytochemical variability of samples, and led to the annotation of 88 metabolites, including a multitude of minor cannabinoids. Multivariate analysis substantiated a strong effect of harvesting year in sample discrimination and related biomarkers were revealed, belonging to fatty acids and flavonoids. The effect of geographical region and, especially, variety on chemical variation patterns was more intricate to interpret. The results of this work are envisioned to enhance our understanding of the real-world phytochemical complexity of C. sativa (hemp), with a view to maximized utilization of hemp for the promotion of human well-being.

Development of Pure Certified Reference Material of Cannabidiol

Cannabidiol (CBD) is the major functional component in hemp and has a broad range of pharmacological applications, such as analgesic, anti-epileptic, anti-anxiety, etc. Currently, CBD is widely used in pharmaceuticals, cosmetics, and food. To ensure the quality and safety of the products containing CBD, more and more related sample testing is being conducted, and the demand for CBD-certified reference material (CRM) has also sharply increased. However, there is currently a lack of relevant reference materials. In this paper, a simple method for preparing CBD CRM was established based on preparative liquid chromatography using crude hemp extract as a raw material. A qualitative analysis of CBD was performed using techniques such as ultraviolet absorption spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), and differential scanning calorimetry (DSC). High-performance liquid chromatography (HPLC) was used for the homogeneity and stability tests, and the data were analyzed using an F-test and a T-test, respectively. Then, eight qualified laboratories were chosen for the determination of a certified value using HPLC. The results show that the CBD CRM had excellent homogeneity and good stability for 18 months. The certified value was 99.57%, with an expanded uncertainty of 0.24% (p = 0.95, k = 2). The developed CBD CRM can be used for the detection and quality control of cannabidiol products.

Predicting binding between 55 cannabinoids and 4,799 biological targets by in silico methods

Recently, there has been an increase in cannabis-derived products being marketed as foods, dietary supplements, and other consumer products. Cannabis contains over a hundred cannabinoids, many of which have unknown physiological effects. Since there are large numbers of cannabinoids, and many are not commercially available for in vitro testing, an in silico tool (Chemotargets Clarity software) was used to predict binding between 55 cannabinoids and 4,799 biological targets (enzymes, ion channels, receptors, and transporters). This tool relied on quantitative structure activity relationships (QSAR), structural similarity, and other approaches to predict binding. From this screening, 827 cannabinoid-target binding pairs were predicted, which included 143 unique targets. Many cannabinoids sharing core structures (cannabinoid "types") had similar binding profiles, whereas most cannabinoids containing carboxylic acid groups were similar without regards to their core structure. For some of the binding predictions (43), in vitro binding data were available, and they agreed well with in silico binding data (median fourfold difference in binding concentrations). Finally, clinical adverse effects associated with 22 predicted targets were identified from an online database (Clarivate Off-X), providing important insights on potential human health hazards. Overall, in silico biological target predictions are a rapid means to identify potential hazards due to cannabinoid-target interactions, and the data can be used to prioritize subsequent in vitro and in vivo testing.

Isolation and Characterization of Impurities in Commercially Marketed Δ8-THC Products

Qualitative analysis of several commercial products containing Δ⁸-tetrahydrocannabinol (Δ⁸-THC) as a major component using GC-MS resulted in the identification of several impurities along with Δ⁸-THC. In an attempt to isolate and identify these impurities, a commercial Δ⁸-THC distillate was selected for the isolation work. Eleven impurities were isolated using a variety of chromatographic techniques, and their chemical structures were determined. These include Δ^4,8-iso-tetrahydrocannabinol (1), Δ⁴-iso-tetrahydrocannabinol (2), Δ⁸-cis-iso-tetrahydrocannabinol (3), 4,8-epoxy-iso-tetrahydrocannabinol (4), 8-hydroxy-iso-tetrahydrocannabinol (5), 9β-hydroxyhexahydrocannabinol (6), 9α-hydroxyhexa-hydrocannabinol (7), iso-tetrahydrocannabifuran (8), cannabicitran (CBT, 9), olivetol (10), and Δ⁹-THC (11). The chemical structures of the purified compounds were determined using several spectroscopic methods, including 1D (¹H, ¹³C, and DEPT-135) and 2D (COSY, HMQC, HMBC, and NOESY) NMR, LC-MS, and GC-MS. Other naturally occurring cannabinoids and impurities were also identified in GC-MS chromatograms but were not isolated. These were cannabidiol (CBD, 12), cannabinol (CBN, 13), hexahydrocannabinol (HHC, 14), and Δ⁸-tetrahydrocannabivarin (Δ⁸-THCV, 15). The chemical structure of Δ⁸-THCV (15), for which a standard was not available, was confirmed by partial synthesis and NMR analysis. This is the first report for many of the above compounds as well as Δ⁸-THCV as impurities in Δ⁸-THC products.

Enantioseparation of chiral phytocannabinoids in medicinal cannabis

The evaluation of the chiral composition of phytocannabinoids in the cannabis plant is particularly important as the pharmacological effects of the (+) and (-) enantiomers of these compounds are completely different. Chromatographic attempts to assess the presence of the minor (+) enantiomers of the main phytocannabinoids, cannabidiolic acid (CBDA) and trans-Δ⁹-tetrahydrocannabinolic acid (trans-Δ⁹-THCA), were carried out on heated plant extracts for the determination of the corresponding decarboxylated species, cannabidiol (CBD) and trans-Δ⁹-tetrahydrocannabinol (trans-Δ⁹-THC), respectively. This process produces an altered phytocannabinoid composition with several new and unknown decomposition products. The present work reports for the first time the stereoselective synthesis of the pure (+) enantiomers of the main phytocannabinoids, trans-CBDA, trans-Δ⁹-THCA, trans-CBD and trans-Δ⁹-THC, and the development and optimization of an achiral-chiral liquid chromatography method coupled to UV and high-resolution mass spectrometry detection in reversed phase conditions (RP-HPLC-UV-HRMS) for the isolation of the single compounds and evaluation of their actual enantiomeric composition in plant. The isolation of the peaks with the achiral stationary phase ensured the absence of interferences that could potentially co-elute with the analytes of interest in the chiral analysis. The method applied to the Italian medicinal cannabis variety FM2 revealed no trace of the (+) enantiomers for all phytocannabinoids under investigation before and after decarboxylation, thus suggesting that the extraction procedure does not lead to an inversion of configuration.

Development and validation of a fit-for-purpose UHPLC-ESI-MS/MS method for the quantitation of cannabinoids in different matrices

Several cannabinoids (cannabidivarin (CBDV), cannabigerol (CBG), cannabidiol (CBD), cannabinol (CBN) and cannabichromene (CBC)) and ethanol hemp extract are being used in primary human hepatocytes (PHH), Caenorhabditis elegans (C. elegans) and in vitro buccal membrane absorption models to elucidate their potential toxicological mechanisms, evaluate their oromucosal absorption, and to identify their metabolites. William's E medium, C. elegans habitation medium (CeHM), and HEPES-buffered hanks' balanced salt solution (HHBSS) are matrices used with these predictive test systems. Therefore, we developed and validated a sensitive fit-for-purpose ultra-high performance liquid chromatography-electrospray-tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the quantitation of CBDV, CBG, CBD, CBN, and CBC in extracellular matrices used with these models for the first time. The separation of the analytes was performed on a Waters ACQUITY UPLC BEH C18 column (130 Å, 1.7 μm, 2.1 × 100 mm) protected with a Waters ACQUITY UPLC BEH C18 guard column (130 Å, 1.7 μm, 2.1 × 5 mm). Positive electrospray ionization and multiple reaction monitoring (MRM) modes were used. Under the developed experimental conditions, good linearities were obtained over the concentration range of 0.025-40 µg/ml with coefficients of determination (R²) varying from 0.9953 to 0.9998. The intra-day precisions were between 0.5 and 9.6% with accuracies within ± 16.7%, and the inter-day precisions ranged from 0.6 to 13.1 % with accuracies within ± 13.7%. The method recoveries were between 85.8 and 105.1%. In addition, time-consuming sample preparation was avoided by applying a simple and efficient extraction procedure, which meets the need for potential large-scale routine analysis. The described method was successfully applied to quantitate the analytes in samples produced with different models as well as in ethanolic hemp extract.

"Breaking bud": the effect of direct chemical modifications of phytocannabinoids on their bioavailability, physiological effects, and therapeutic potential

Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the two "major cannabinoids". However, their incorporation into clinical and nutraceutical preparations is challenging, owing to their limited bioavailability, low water solubility, and variable pharmacokinetic profiles. Understanding the organic chemistry of the major cannabinoids provides us with potential avenues to overcome these issues through derivatization. The resulting labile pro-drugs offer ready cannabinoid release in vivo, have augmented bioavailability, or demonstrate interesting pharmacological properties in their own right. This review identifies and discusses a subset of these advanced derivatization strategies for the major cannabinoids, where the starting material is the pure phytocannabinoid itself, and the final product either a cannabinoid pro-drug, or a novel pharmacoactive material.

UPLC-ESI-QTOF-MS/MS Analysis of the Phytochemical Compositions From Chaenomeles speciosa (Sweet) Nakai Fruits

Chaenomeles speciosa (Sweet) Nakai (C. speciosa Nakai) is a popular fruit widely used in China for its health-promoting properties. The presences of phytochemical compositions in the plants play an important role in the health benefits. Nevertheless, the detailed information of these ingredients is still unknown. Therefore, in this work, an untargeted analytical method based on ultra-high-performance liquid chromatography-quadrupole-time of flight coupled to mass spectrometry in two different ionization modes was used to qualitative the phytochemicals in C. speciosa Nakai, meanwhile, the anti-inflammatory activity of these phytochemicals was researched through detecting the inhibition of nitric oxide (NO) that was induced by lipopolysaccharide in RAW 264.7 murine macrophage cells. The results showed that there were totally 175 primary and secondary metabolites were identified in the fruit of C. speciosa Nakai, including phenols, terpenoids, flavonoids and other phyto-constituents. Actually, most compounds were described in C. speciosa Nakai fruits for the first time. Besides, the anti-inflammatory activity was measured by the result of NO inhibition rate, the consequence showed that the value of half-inhibitory concentration (IC50) was 365.208 μg/mL. These results indicate that C. speciosa Nakai is an efficient medicinal fruit, which owns various bioactivities and has the potential to treat various diseases.

Use of near-infrared spectroscopy for the classification of medicinal cannabis cultivars and the prediction of their cannabinoid and terpene contents

Cannabis sativa L. is used to treat a wide variety of medical conditions, in light of its beneficial pharmacological properties of its cannabinoids and terpenes. At present, the quantitative chemical analysis of these active compounds is achieved through the use of laborious, expensive, and time-consuming technologies, such as high-pressure liquid-chromatography- photodiode arrays, mass spectrometer detectors (HPLC-PDA or MS), or gas chromatography-mass spectroscopy (GC-MS). Hence, we aimed to develop a simple, accurate, fast, and cheap technique for the quantification of major cannabinoids and terpenes using Fourier transform near infra-red spectroscopy (FT-NIRS). FT-NIRS was coupled with multivariate classification and regression models, namely partial least square-discriminant analysis (PLS-DA) and partial least squares regression (PLS-R) models. The PLS-DA model yielded an absolute major class separation (high-THC, high-CBD, hybrid, and high-CBG) and perfect class prediction. Using only three latent variables (LVs), the cross-validation and prediction model errors indicated a low probability of over-fitting the data. In addition, the PLS-DA model enabled the classification of chemovars with genetic-chemical similarities. The classification of high-THCA chemovars was more sensitive and more specific than the classifications of the remaining chemovars. The prediction of cannabinoid and terpene concentrations by PLS-R yielded 11 robust models with high predictive capabilities (R2CV and R2pred > 0.8, RPD >2.5 and RPIQ >3, RMSECV/RMSEC ratio <1.2) and additional 15 models whose performance was acceptable for initial screening purposes (R2CV > 0.7 and R2pred < 0.8, RPD >2 and RPIQ <3, 1.2 < RMSECV/RMSEC ratio <2). Our results confirm that there is sufficient information in the FT-NIRS to develop cannabinoid and terpene prediction models and major-cultivar classification models.

Characterizing the degradation of cannabidiol in an e-liquid formulation

The reported characteristics of cannabidiol (CBD) have encouraged significant growth in commercial CBD products. There is limited information on the stability of CBD and some researchers have noted significant reductions of CBD in products. In this study, the chemical profiles of plant-based and chemically synthesized CBD in a prototype e-liquid formulation were assessed during 4 weeks of storage under varying conditions. Samples were analysed on days 1, 8, 15, 22, and 29 by untargeted analysis using ultra-high performance liquid chromatography-trapped ion mobility-time-of-flight mass spectrometry (UHPLC-TIMS-TOF-MS). On day 1, analysis of plant-based and synthetic CBD formulations showed small differences in their composition, with plant-based CBD e-liquid containing trace levels of a higher number of phytocannabinoid-related impurities. Storage for 4 weeks under stress (40 °C, 75% relative humidity, dark) and ambient (25 °C, 60% relative humidity, daylight) conditions led to increases in the number and abundance of cannabinoid-related degradation products, including cannabielsoin (CBE) and CBD-hydroxyquinone (HU-331), which are products of the oxidation of CBD, and other unidentified cannabinoid-related compounds. The unidentified cannabinoid-related compounds were probed by accurate mass measurement and MS² fragmentation but could not be matched using a mass spectral library derived from 39 commercially available cannabinoid reference standards. Based on elemental composition and MS² fragmentation patterns, the unidentified cannabinoid-related compounds were classified as hydroxy-CBE, hydroxy-CBD, and dihydroxy-CBD. The analysis of e-liquid formulations protected from light and stored at 4 °C for 4 weeks indicated only very small increases in CBD oxidation products. The results indicate that CBD degrades in e-liquid solution at ambient temperature in dark and light to form potentially undesirable products, including cannabielsoin and cannabidiol hydroxyquinone.

Biosynthetic origins of unusual cannabimimetic phytocannabinoids in Cannabis sativa L: A review

Plants of Cannabis sativa L. (Cannabaceae) produce an array of more than 160 isoprenylated resorcinyl polyketides, commonly referred to as phytocannabinoids. These compounds represent molecules of therapeutic importance due to their modulation of the human endocannabinoid system (ECS). While understanding of the biosynthesis of the major phytocannabinoids Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD) has grown rapidly in recent years, the biosynthetic origin and genetic regulation of many potentially therapeutically relevant minor phytocannabinoids remain unknown, which limits the development of chemotypically elite varieties of C. sativa. This review provides an up-to-date inventory of unusual phytocannabinoids which exhibit cannabimimetic-like activities and proposes putative metabolic origins. Metabolic branch points exploitable for combinatorial biosynthesis and engineering of phytocannabinoids with augmented therapeutic activities are also described, as is the role of phytocannabinoid remodelling to accelerate the therapeutic portfolio expansion in C. sativa.

Multivariate classification of cannabis chemovars based on their terpene and cannabinoid profiles

Cannabis is used to treat various medical conditions, and lines are commonly classified according to their total concentrations of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Based on their ratio of total THC to total CBD, cannabis cultivars are commonly classified into high-THC, high-CBD, and hybrid classes. While cultivars from the same class have similar compositions of major cannabinoids, their levels of other cannabinoids and their terpene compositions may differ substantially. Therefore, a more comprehensive and accurate classification of medicinal cannabis cultivars, based on a large number of cannabinoids and terpenes is needed. For this purpose, three different chemometric-based classification models were constructed using three sets of chemical profiles. We examined those models to determine which provides the most accurate "chemovar" classification. This was done by analyzing profiles of cannabinoids, terpenes, and the combination of these substances using the partial least square-discriminant analysis multivariate (PLS-DA) technique. The chemical profiles were selected from the three major classes of medicinal cannabis that are most commonly prescribed to patients in Israel: high-THC, high-cannabigerol (CBG), and hybrid. We studied the correlations between cannabinoids and terpenes to identify major bio-indicators representing the plant's terpene and cannabinoid content. All three PLS-DA models provided highly accurate classifications, utilizing six to nine latent variables with an overall accuracy ranging from 2 to 11% CV. The PLS-DA model applied to the combined cannabinoid-and-terpene profile did the best job of differentiating between the chemovars in terms of misclassification error, sensitivity, specificity, and accuracy. The combined cannabinoid-and-terpene PLS-DA profile had cross-validation and prediction misclassification errors of 4% and 0%, respectively. This is the first study to demonstrate the highly accurate classification of samples of medicinal cannabis based on their cannabinoid and terpene profiles, as compared to cannabinoid profiles alone. Furthermore, our correlation analysis indicated that 11 cannabinoids and terpenes might serve as bio-indicators for 32 different active compounds. These findings suggest that the use of multivariate statistics could assist in breeding studies and serve as a tool for minimizing the mislabeling of cannabis inflorescences.

A Nrf-2 Stimulatory Hydroxylated Cannabidiol Derivative from Hemp (Cannabis sativa)

A phytochemical analysis of mother liquors obtained from crystallization of CBD from hemp (Cannabis sativa), guided by LC-MS/MS and molecular networking profiling and completed by isolation and NMR-based characterization of constituents, resulted in the identification of 13 phytocannabinoids. Among them, anhydrocannabimovone (5), isolated for the first time as a natural product, and three new hydroxylated CBD analogues (1,2-dihydroxycannabidiol, 6, 3,4-dehydro-1,2-dihydroxycannabidiol, 7, and hexocannabitriol, 8) were obtained. Hexocannabitriol (8) potently modulated, in a ROS-independent way, the Nrf2 pathway, outperforming all other cannabinoids obtained in this study and qualifying as a potential new chemopreventive chemotype against cancer and other degenerative diseases.

Beyond Δ9-tetrahydrocannabinol and cannabidiol: chemical differentiation of cannabis varieties applying targeted and untargeted analysis

Cannabis sativa (C. sativa) is commonly chemically classified based on its Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD) content ratios. However, the plant contains nearly 150 additional cannabinoids, referred to as minor cannabinoids. Minor cannabinoids are gaining interest for improved plant and product characterization, e.g., for medical use, and bioanalytical questions in the medico-legal field. This study describes the development and validation of an analytical method for the elucidation of minor cannabinoid fingerprints, employing liquid chromatography coupled to high-resolution mass spectrometry. The method was used to characterize inflorescences from 18 different varieties of C. sativa, which were cultivated under the same standardized conditions. Complementing the targeted detection of 15 cannabinoids, untargeted metabolomics employing in silico assisted data analysis was used to detect additional plant ingredients with focus on cannabinoids. Principal component analysis (PCA) was used to evaluate differences between varieties. The overall purpose of this study was to examine the ability of targeted and non-targeted metabolomics using the mentioned techniques to distinguish cannabis varieties from each other by their minor cannabinoid fingerprint. Quantitative determination of targeted cannabinoids already gave valuable information on cannabinoid fingerprints as well as inter- and intra-variety variability of cannabinoid contents. The untargeted workflow led to the detection of 19 additional compounds. PCA of the targeted and untargeted datasets revealed further subgroups extending commonly applied phenotype classification systems of cannabis. This study presents an analytical method for the comprehensive characterization of C. sativa varieties.

Cannabinoid Profile in Cannabis sativa L. Samples by Means of LC-MRM/IDA/EPI Analysis: A New Approach for Cultivar Classification

A new multitarget screening procedure for 36 cannabinoids in 12 Cannabis sativa L. cultivars (hemp) was developed using multiple reaction monitoring (MRM) coupled with an enhanced product ion (EPI) scan in an information-dependent acquisition (IDA) experiment, which can be performed by means of high-performance liquid chromatography-mass spectrometry (HPLC-MS)/MS analysis. The MRM-IDA-EPI experiment was used for the analysis of hemp samples and the identification of the compounds of interest. It was performed through the comparison of EPI spectra with literature data and with the in-house library. The results, processed by multivariate statistical analysis, showed an accurate classification of the 12 C. sativa cultivars, emphasizing the synergic contribution of the new cannabinoids recently discovered and showing how the traditional classification based on a common cannabinoid is limiting.

Natural products in suppressing glioma progression: A focus on the role of microRNAs

Glioma is one of the most common malignancies of the central nervous system. Due to inadequate response to the current treatments available, glioma has been at the center of recent cancer studies searching for novel treatment strategies. This has prompted an intensive search using linkage studies and preliminary evidence to gain efficient insight into the mechanisms involved in the alleviation of the pathogenesis of glioma mediated by miRNAs, a group of noncoding RNAs that affect gene expression posttranscriptionally. Dysregulated expression of miRNAs can exacerbate the malignant features of tumor cells in glioma and other cancers. Natural products can exert anticancer effects on glioma cells by stimulating the expression levels of tumor suppressor miRNAs and repressing the expression levels of oncogenic miRNAs. In this review, we aimed to collect and analyze the literature addressing the roles of natural products in the treatment of glioma, with an emphasis on their involvement in the regulation of miRNAs.

The novel heptyl phorolic acid cannabinoids content in different Cannabis sativa L. accessions

The recent discovery of the novel heptyl phytocannabinoids cannabidiphorol (CBDP) and Δ⁹-tetrahydrocannabiphorol (Δ⁹-THCP) raised a series of questions relating to the presence and abundance of these new unorthodox compounds in cannabis inflorescence or derived products. As fresh inflorescence contains mainly their acid precursors, which are not commercially available, an ad hoc stereoselective synthesis was performed in order to obtain cannabidiphorolic acid (CBDPA) and Δ⁹-tetrahydrocannabiphorolic acid (THCPA) to be used as analytical standards for quantitative purposes. The present work reports an unprecedented targeted analysis of both pentyl (C5) and heptyl (C7) CBD- and THC-type compounds in forty-nine cannabis samples representing four different chemotypes. Moreover, the ultrahigh performance liquid chromatography coupled to high-resolution mass spectrometry-based method was applied for the putative identification of other heptyl homologs of the most common phytocannabinoid acids, including cannabigerophorolic acid (CBGPA), cannabichromephorolic acid (CBCPA), cannabinophorolic acid (CBNPA), cannabielsophorolic acid (CBEPA), cannabicyclophorolic acid (CBLPA), cannabitriophorolic acid (CBTPA), and cannabiripsophorolic acid (CBRPA).

Targeted and untargeted characterization of underivatized policosanols in hemp inflorescence by liquid chromatography-high resolution mass spectrometry

The paper describes the development of a targeted quantitative method for the analysis of policosanols in hemp inflorescence. Policosanols are long chain aliphatic alcohols, with carbon chains typically in the range 20-36, with interesting biological activities. These compounds are typically separated by gas chromatography and only a few methods employ liquid chromatography for policosanols. In both cases, methods always include the derivatization of policosanols. In this study, policosanols were separated by ultra-high performance liquid chromatography without any derivatization and detected using high resolution mass spectrometry by formation of lithiated adducts. The procedure was optimized and a quantitative method was validated for the most abundant policosanols (with C24, C26, C27, C28, and C30 chain lengths) in industrial hemp inflorescence extracts. The method was used for the quantitative analysis of policosanols in five hemp types. Hemp wax was found rich in these compounds, especially C26 and C28 policosanols, which may prove useful for revalorization of wax by-products. Finally, the acquired data were also used to expand the search to the untargeted qualitative analysis of policosanols using Compound Discoverer. The untargeted method allowed the annotation of underivatized policosanols up to C33.

Cannabinoids vs. whole metabolome: Relevance of cannabinomics in analyzing Cannabis varieties

Cannabis sativa has a long history of domestication both for its bioactive compounds and its fibers. This has produced hundreds of varieties, usually characterized in the literature by chemotypes, with Δ⁹-THC and CBD content as the main markers. However, chemotyping could also be done based on minor compounds (phytocannabinoids and others). In this work, a workflow, which we propose to name cannabinomics, combines mass spectrometry of the whole metabolome and statistical analysis to help differentiate C. sativa varieties and deciphering their characteristic markers. By applying this cannabinomics approach to the data obtained from 20 varieties of C. sativa (classically classified as chemotype I, II, or III), we compared the results with those obtained by a targeted quantification of 11 phytocannabinoids. Cannabinomics can be considered as a complementary tool for phenotyping and genotyping, allowing the identification of minor compounds playing a key role as markers of differentiation.

Recent applications of mass spectrometry for the characterization of cannabis and hemp phytocannabinoids: From targeted to untargeted analysis

This review is a collection of recent applications of mass spectrometry studies for the characterization of phytocannabinoids in cannabis and hemp plant material and related products. The focus is mostly on recent applications using mass spectrometry as detector, in hyphenation to typical separation techniques (i.e., liquid chromatography or gas chromatography), but also with less common couplings or by simple direct analysis. The papers are described starting from the most common approach for targeted quantitative analysis, with applications using low-resolution mass spectrometry equipment, but also with the introduction of high-resolution mass analyzers as the detectors. This reflects a common trend in this field, and introduces the most recent applications using high-resolution mass spectrometry for untargeted analysis. The different approaches used for untargeted analysis are then described, from simple retrospective analysis of compounds without pure standards, through untargeted metabolomics strategies, and suspect screening methods, which are the ones currently allowing to achieve the most detailed qualitative characterization of the entire phytocannabinoid composition, including minor compounds which are usually overlooked in targeted studies and in potency evaluation. These approaches also represent powerful strategies to answer questions on biological and pharmacological activity of cannabis, and provide a sound technology for improved classification of cannabis varieties. Finally, open challenges are discussed for future directions in the detailed study of complex phytocannabinoid mixtures.

Oxidative Stress and Multi-Organel Damage Induced by Two Novel Phytocannabinoids, CBDB and CBDP, in Breast Cancer Cells

Over the last few years, much attention has been paid to phytocannabinoids derived from Cannabis for their therapeutic potential. Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD) are the most abundant compounds of the Cannabis sativa L. plant. Recently, novel phytocannabinoids, such as cannabidibutol (CBDB) and cannabidiphorol (CBDP), have been discovered. These new molecules exhibit the same terpenophenolic core of CBD and differ only for the length of the alkyl side chain. Roles of CBD homologs in physiological and pathological processes are emerging but the exact molecular mechanisms remain to be fully elucidated. Here, we investigated the biological effects of the newly discovered CBDB or CBDP, compared to the well-known natural and synthetic CBD (nat CBD and syn CBD) in human breast carcinoma cells that express CB receptors. In detail, our data demonstrated that the treatment of cells with the novel phytocannabinoids affects cell viability, increases the production of reactive oxygen species (ROS) and activates cellular pathways related to ROS signaling, as already demonstrated for natural CBD. Moreover, we observed that the biological activity is significantly increased upon combining CBD homologs with drugs that inhibit the activity of enzymes involved in the metabolism of endocannabinoids, such as the monoacylglycerol lipase (MAGL) inhibitor, or with drugs that induces the activation of cellular stress pathways, such as the phorbol ester 12-myristate 13-acetate (PMA).

Phytocannabinomics: Untargeted metabolomics as a tool for cannabis chemovar differentiation

Cannabis sativa is traditionally classified according to five chemotypes based on the concentration of the main phytocannabinoids tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabigerol (CBG). However, cannabis chemovars and varieties very often present similar concentrations of such phytocannabinoids but different chemical profiles, which is unavoidably translated into different pharmacological effects when used for therapeutic purposes. For this reason, a more refined approach is needed for chemovar distinction, which is described in this study and named phytocannabinomics. The classification was achieved by a comprehensive characterization of the phytocannabinoid composition, by liquid chromatography coupled to high-resolution mass spectrometry untargeted metabolomics for the detection of over a hundred phytocannabinoids, and data analysis by chemometrics for chemovars differentiation. The method was developed on fifty cannabis varieties, grown under the same conditions, and was validated to discriminate between the standard chemotypes by partial least squares discriminant analysis. Then, the method was extended to consider the entire chemical variety of the cannabis accessions, by an unsupervised approach based on the principal component analysis. The latter approach clearly indicated several new subgroups within the traditional classifications, which arise from a unique composition of the minor phytocannabinoids. The existence of these subgroups, which were never described before, is of critical importance for evaluating the pharmacological effects of cannabis chemovars.

HPLC-UV-HRMS analysis of cannabigerovarin and cannabigerobutol, the two impurities of cannabigerol extracted from hemp

A sensitive and straightforward HPLC-UV method was developed for the simultaneous quantification of the two main impurities in "pure" commercial cannabigerol (CBG) samples. The identification of such impurities, namely cannabigerovarin (CBGV) and cannabigerobutol (CBGB), the propyl and butyl homologs of CBG, respectively, was accomplished employing the high-resolution mass spectrometry (HRMS) technique, and subsequently confirmed by comparison with the same compounds obtained by chemical synthesis. Complete spectroscopic characterization (NMR, FT-IR, UV, and HRMS) of both impurities is reported in the present work. The method was validated in terms of linearity, which was assessed in the range 0.01-1.00 μg/mL, sensitivity, selectivity, intra- and inter-day accuracy and precision, and short-term stability, which all satisfied the acceptance criteria of the ICH guidelines. Application of the method to the analysis of four commercial CBG samples highlighted a certain variability in the impurity profile that might be ascribed to the hemp variety of the starting plant material. With these new analytical standards in hand, it would be interesting to investigate their concentrations in different hemp varieties and expand the scope of a phytocannabinomics approach for a comprehensive profiling of this remarkable class of natural compounds.

Potency testing of cannabinoids by liquid and supercritical fluid chromatography: Where we are, what we need

Hemp and cannabis industry is undergoing a renewed interest due to legalization of marijuana (a topic that all countries are discussing, especially in recent years) and the growing importance of therapeutic properties of cannabinoids. Together with an increment in the production of hemp and recreational cannabis, there has been an increasing demand for accurate potency testing of products (i.e. quantification of main cannabinoids present in the plant in terms of weight percentage) prior commercialization. This translates in an urgent need of reliable analytical methods to characterize cannabis and hemp samples. Cannabis and hemp preparations are commercialized under various forms (e.g., flowers, oils, candies or even baked goods) usually containing a large number of often very similar compounds making their separation very challenging. Strictly connected to this, another emerging topic concerns the need for the developing of large scale separation techniques for the purification of cannabinoids from complex matrices and for the preparation of analytical-grade standards (including the chiral ones). This paper reviews the most recent achievements in both these aspects. Cutting-edge applications and novel opportunities in potency testing by high performance liquid chromatography (HPLC) with UV detection (which is becoming the golden standard, according to several pharmacopeias, for this kind of measurements) are discussed. The focus has been given to the very important topic of enantio-discrimination of chiral cannabinoids, for which supercritical fluid chromatography (SFC) appears to be particularly suitable. The last part of the work covers the purification of cannabinoids through preparative chromatography. In this regard, particular attention has been given to the most innovative multi-column techniques allowing for the continuous purification of target molecules. The most recent advancements and future challenges in this field are discussed.

Specific phytocannabinoid compositions are associated with analgesic response and adverse effects in chronic pain patients treated with medical cannabis

Medical cannabis (MC) treatment for chronic pain is increasing, but evidence regarding short- and long-term efficacy and associated adverse effects (AEs) of the different cannabis plant components is limited. Most reports focus on two phytocannabinoids, (-)-Δ⁹-trans-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD). This study, aimed to identify patterns of phytocannabinoid compositions associated with MC treatment response and with related AEs. Participants in this multicenter prospective cohort were patients with chronic non-cancer pain that were prescribed MC by physicians. Data was collected before MC treatment, at one month (short-term) and at 12 months (long-term). Simultaneously, liquid chromatography mass spectrometry identification and quantification of phytocannabinoids from the cultivars were performed. The monthly dose of each phytocannabinoid for each patient was z-scaled and clustered into ten groups to assess the difference in analgesic treatment response (≥30%/50% pain intensity reduction) and AEs rates. We identified ten clusters that had similar analgesic treatment response rates. However, there were significant differences in AEs rates both at short- and long-term. We identified specific phytocannabinoid compositions that were associated with overall AEs rates (5% compared to 53% at short-term and 44% at long-term) and with specific AEs rates such as MC related central nervous system, gastrointestinal and psychological AEs. To conclude, Evaluating only Δ9-THC or CBD is insufficient to find associations with MC related AEs. Therefore, comprehensive profiling of phytocannabinoids is needed to discover associations to related AEs and help physicians prescribe safer cannabis with less AEs while still relieving pain.

Biosynthesis of Nature-Inspired Unnatural Cannabinoids

Natural products make up a large proportion of medicine available today. Cannabinoids from the plant Cannabis sativa is one unique class of meroterpenoids that have shown a wide range of bioactivities and recently seen significant developments in their status as therapeutic agents for various indications. Their complex chemical structures make it difficult to chemically synthesize them in efficient yields. Synthetic biology has presented a solution to this through metabolic engineering in heterologous hosts. Through genetic manipulation, rare phytocannabinoids that are produced in low yields in the plant can now be synthesized in larger quantities for therapeutic and commercial use. Additionally, an exciting avenue of exploring new chemical spaces is made available as novel derivatized compounds can be produced and investigated for their bioactivities. In this review, we summarized the biosynthetic pathways of phytocannabinoids and synthetic biology efforts in producing them in heterologous hosts. Detailed mechanistic insights are discussed in each part of the pathway in order to explore strategies for creating novel cannabinoids. Lastly, we discussed studies conducted on biological targets such as CB1, CB2 and orphan receptors along with their affinities to these cannabinoid ligands with a view to inform upstream diversification efforts.

Origin of Δ9-Tetrahydrocannabinol Impurity in Synthetic Cannabidiol

Introduction: Cannabidiol (CBD), the nonintoxicating constituent of cannabis, is largely employed for pharmaceutical and cosmetic purposes. CBD can be extracted from the plant or chemically synthesized. Impurities of psychotropic cannabinoids Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and Δ⁸-THC have been found in extracted CBD, thus hypothesizing a possible contamination from the plant. Materials and Methods: In this study, synthetic and extracted CBD samples were analyzed by ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry and the parameters that can be responsible of the conversion of CBD into THC were evaluated by an accelerated stability test. Results: In synthetic and extracted CBD no trace of THC species was detected. In contrast, CBD samples stored in the dark at room temperature on the benchtop for 3 months showed the presence of such impurities. Experiments carried out under inert atmosphere in the absence of humidity or carbon dioxide led to no trace of THC over time even at high temperature. Conclusions: The results suggested that the copresence of carbon dioxide and water from the air could be the key for creating the acidic environment responsible for the cyclization of CBD. These findings suggest that it might be appropriate to review the storage conditions indicated on the label of commercially available CBD.

Phytocannabinoid Pharmacology: Medicinal Properties of Cannabis sativa Constituents Aside from the "Big Two"

Plant-based therapies date back centuries. Cannabis sativa is one such plant that was used medicinally up until the early part of the 20th century. Although rich in diverse and interesting phytochemicals, cannabis was largely ignored by the modern scientific community due to its designation as a schedule 1 narcotic and restrictions on access for research purposes. There was renewed interest in the early 1990s when the endocannabinoid system (ECS) was discovered, a complex network of signaling pathways responsible for physiological homeostasis. Two key components of the ECS, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), were identified as the molecular targets of the phytocannabinoid Δ⁹-tetrahydrocannabinol (Δ⁹-THC). Restrictions on access to cannabis have eased worldwide, leading to a resurgence in interest in the therapeutic potential of cannabis. Much of the focus has been on the two major constituents, Δ⁹-THC and cannabidiol (CBD). Cannabis contains over 140 phytocannabinoids, although only a handful have been tested for pharmacological activity. Many of these minor cannabinoids potently modulate receptors, ionotropic channels, and enzymes associated with the ECS and show therapeutic potential individually or synergistically with other phytocannabinoids. The following review will focus on the pharmacological developments of the next generation of phytocannabinoid therapeutics.

Cannabis Sativa L.: a comprehensive review on the analytical methodologies for cannabinoids and terpenes characterization

The global Cannabis Sativa market, including essential oils, foods, personal-care products, and medical formulations has gained much attention over the last years due to the favorable regulatory framework. Undoubtedly, the enormous interest about cannabis cultivation mainly derives from the well-known pharmacological properties of cannabinoids and terpenes biosynthesized by the plants. In this review, the most recently used analytical methodologies for detecting both cannabinoids and terpenes are described. Well-established and innovative extraction protocols, and chromatographic separations, such as GC and HPLC, are reviewed highlighting their respective advantages and drawbacks. Lastly, GC × GC techniques are also reported for accurate identification and quantification of terpenes in complex cannabis matrices.

Identification of a new cannabidiol n-hexyl homolog in a medicinal cannabis variety with an antinociceptive activity in mice: cannabidihexol

The two most important and studied phytocannabinoids present in Cannabis sativa L. are undoubtedly cannabidiol (CBD), a non-psychotropic compound, but with other pharmacological properties, and Δ⁹-tetrahydrocannabinol (Δ⁹-THC), which instead possesses psychotropic activity and is responsible for the recreative use of hemp. Recently, the homolog series of both CBDs and THCs has been expanded by the isolation in a medicinal cannabis variety of four new phytocannabinoids possessing on the resorcinyl moiety a butyl-(in CBDB and Δ⁹-THCB) and a heptyl-(in CBDP and Δ⁹-THCP) aliphatic chain. In this work we report a new series of phytocannabinoids that fills the gap between the pentyl and heptyl homologs of CBD and Δ⁹-THC, bearing a n-hexyl side chain on the resorcinyl moiety that we named cannabidihexol (CBDH) and Δ⁹-tetrahydrocannabihexol (Δ⁹-THCH), respectively. However, some cannabinoids with the same molecular formula and molecular weight of CBDH and Δ⁹-THCH have been already identified and reported as monomethyl ether derivatives of the canonical phytocannabinoids, namely cannabigerol monomethyl ether (CBGM), cannabidiol monomethyl ether (CBDM) and Δ⁹-tetrahydrocannabinol monomethyl ether (Δ9-THCM). The unambiguously identification in cannabis extract of the n-hexyl homologues of CBD and Δ⁹-THC different from the corresponding methylated isomers (CBDM, CBGM and Δ⁹-THCM) was achieved by comparison of the retention time, molecular ion, and fragmentation spectra with those of the authentic standards obtained via stereoselective synthesis, and a semi-quantification of these cannabinoids in the FM2 medical cannabis variety was provided. Conversely, no trace of Δ⁹-THCM was detected. Moreover, CBDH was isolated by semipreparative HPLC and its identity was confirmed by comparison with the spectroscopic data of the corresponding synthetic standard. Thus, the proper recognition of CBDH, CBDM and Δ⁹-THCH closes the loop and might serve in the future for researchers to distinguish between these phytocannabinoids isomers that show a very similar analytical behaviour. Lastly, CBDH was assessed for biological tests in vivo showing interesting analgesic activity at low doses in mice.

The Essential Medicinal Chemistry of Cannabidiol (CBD)

This Perspective of the published essential medicinal chemistry of cannabidiol (CBD) provides evidence that the popularization of CBD-fortified or CBD-labeled health products and CBD-associated health claims lacks a rigorous scientific foundation. CBD's reputation as a cure-all puts it in the same class as other "natural" panaceas, where valid ethnobotanicals are reduced to single, purportedly active ingredients. Such reductionist approaches oversimplify useful, chemically complex mixtures in an attempt to rationalize the commercial utility of natural compounds and exploit the "natural" label. Literature evidence associates CBD with certain semiubiquitous, broadly screened, primarily plant-based substances of undocumented purity that interfere with bioassays and have a low likelihood of becoming therapeutic agents. Widespread health challenges and pandemic crises such as SARS-CoV-2 create circumstances under which scientists must be particularly vigilant about healing claims that lack solid foundational data. Herein, we offer a critical review of the published medicinal chemistry properties of CBD, as well as precise definitions of CBD-containing substances and products, distilled to reveal the essential factors that impact its development as a therapeutic agent.

Cannabitwinol, a Dimeric Phytocannabinoid from Hemp, Cannabis sativa L., Is a Selective Thermo-TRP Modulator

Cannabitwinol (CBDD, 3), the second member of a new class of dimeric phytocannabinoids in which two units are connected by a methylene bridge, was isolated from a hemp (Cannabis sativa L.) industrial extract. The structural characterization of cannabitwinol, complicated by broadening of ¹H NMR signals and lack of expected 2D NMR correlations at room temperature, was fully carried out in methanol-d₄ at -30 °C. All the attempts to prepare CBDD by reaction of CBD with formaldehyde or its iminium analogue (Eschenmoser salt) failed, suggesting that this sterically congested dimer is the result of enzymatic reactions on the corresponding monomeric acids. Analysis of the cannabitwinol profile of transient receptor potential (TRP) modulation evidenced the impact of dimerization, revealing a selectivity for channels activated by a decrease of temperature (TRPM8 and TRPA1) and the lack of significant affinity for those activated by an increase of temperature (e.g., TRPV1). The putative binding modes of cannabitwinol with TRPA1 and TRPM8 were investigated in detail by a molecular docking study using the homology models of both channels.

Emerging challenges in the extraction, analysis and bioanalysis of cannabidiol and related compounds

Cannabidiol (CBD) is a bioactive terpenophenolic compound isolated from Cannabis sativa L. It is known to possess several properties of pharmaceutical interest, such as antioxidant, anti-inflammatory, anti-microbial, neuroprotective and anti-convulsant, being it active as a multi-target compound. From a therapeutic point of view, CBD is most commonly used for seizure disorder in children. CBD is present in both medical and fiber-type C. sativa plants, but, unlike Δ⁹-tetrahydrocannabinol (THC), it is a non-psychoactive compound. Non-psychoactive or fiber-type C. sativa (also known as hemp) differs from the medical one, since it contains only low levels of THC and high levels of CBD and related non-psychoactive cannabinoids. In addition to medical Cannabis, which is used for many different therapeutic purposes, a great expansion of the market of hemp plant material and related products has been observed in recent years, due to its usage in many fields, including food, cosmetics and electronic cigarettes liquids (commonly known as e-liquids). In this view, this work is focused on recent advances on sample preparation strategies and analytical methods for the chemical analysis of CBD and related compounds in both C. sativa plant material, its derived products and biological samples. Since sample preparation is considered to be a crucial step in the development of reliable analytical methods for the determination of natural compounds in complex matrices, different extraction methods are discussed. As regards the analysis of CBD and related compounds, the application of both separation and non-separation methods is discussed in detail. The advantages, disadvantages and applicability of the different methodologies currently available are evaluated. The scientific interest in the development of portable devices for the reliable analysis of CBD in vegetable and biological samples is also highlighted.

Characterization of By-Products from Commercial Cannabidiol Production

The chemical compositions of by-products from commercial cannabidiol (CBD) extraction were characterized and quantitated by employing gas chromatography mass spectrometry (GC-MS) and GC flame-ionization detection (GC-FID). The four major by-products included an ethanol-wax suspension (WAX), terpenoid distillate (DIST-A), tar-like residue (TAR), and red resin (RES). The composition of WAX consisted of ∼28 wt % n-alkanes and ∼33-38 wt % cannabidiolic acid and CBD combined. The DIST-A consisted of ∼40 wt % sesquiterpenoids and ∼58 wt % cannabinoids. The DIST-A terpenoid profile was compared to dried unprocessed inflorescences (HEMP) to observe changes in monoterpene content after the distillation process. The TAR was composed of ∼5-9 wt % higher n-alkanes and up to 91 wt % cannabinoids, while RES consisted of up to 99 wt % cannabinoids. Several impurities including cannabidibutol and dehydroabietic acid were identified in commercial CBD samples. Compositional information of these by-products may provide manufacturers with the opportunity to optimize processing conditions.

Cannabinoids and Cannabinoid Receptors: The Story so Far

Like most modern molecular biology and natural product chemistry, understanding cannabinoid pharmacology centers around molecular interactions, in this case, between the cannabinoids and their putative targets, the G-protein coupled receptors (GPCRs) cannabinoid receptor 1 (CB₁) and cannabinoid receptor 2 (CB₂). Understanding the complex structure and interplay between the partners in this molecular dance is required to understand the mechanism of action of synthetic, endogenous, and phytochemical cannabinoids. This review, with 91 references, surveys our understanding of the structural biology of the cannabinoids and their target receptors including both a critical comparison of the extant crystal structures and the computationally derived homology models, as well as an in-depth discussion about the binding modes of the major cannabinoids. The aim is to assist in situating structural biochemists, synthetic chemists, and molecular biologists who are new to the field of cannabis research.

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Cannabinoid research has greatly expanded

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Structural biology and computational chemistry jointly provide mechanistic insight

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Structural data are being generated at an exponentially increasing rate

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Phytocannabinoid targeting of other GPCR receptors deserves investigation

Is cannabidiol a scheduled controlled substance? Origin makes the difference

Cannabidiol (CBD) is the main cannabinoid naturally occurring in hemp. It has recently attracted the attention of the scientific community because of its numerous pharmacological activities. However, its legal status changes depending on whether it is chemically synthesized or extracted from the plant: extracted CBD is a scheduled controlled substance, whereas synthetic CBD is not under control. In Europe, extracted CBD is excluded from the cosmetic ingredients of the CosIng database. Given the confusion surrounding these different forms of CBD, there is an urgent need for clarity to shed light from both a regulatory and a chemical point of view. The impurity profiles of synthetic and natural CBD are different and could currently represent the only means to distinguish the origin of this substance.

Isolation of a High-Affinity Cannabinoid for the Human CB1 Receptor from a Medicinal Cannabis sativa Variety: Δ9-Tetrahydrocannabutol, the Butyl Homologue of Δ9-Tetrahydrocannabinol

The butyl homologues of Δ⁹-tetrahydrocannabinol, Δ⁹-tetrahydrocannabutol (Δ⁹-THCB), and cannabidiol, cannabidibutol (CBDB), were isolated from a medicinal Cannabis sativa variety (FM2) inflorescence. Appropriate spectroscopic and spectrometric characterization, including NMR, UV, IR, ECD, and HRMS, was carried out on both cannabinoids. The chemical structures and absolute configurations of the isolated cannabinoids were confirmed by comparison with the spectroscopic data of the respective compounds obtained by stereoselective synthesis. The butyl homologue of Δ⁹-THC, Δ⁹-THCB, showed an affinity for the human CB1 (K_i = 15 nM) and CB2 receptors (K_i = 51 nM) comparable to that of (-)-trans-Δ⁹-THC. Docking studies suggested the key bonds responsible for THC-like binding affinity for the CB1 receptor. The formalin test in vivo was performed on Δ⁹-THCB in order to reveal possible analgesic and anti-inflammatory properties. The tetrad test in mice showed a partial agonistic activity of Δ⁹-THCB toward the CB1 receptor.

A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than Δ9-tetrahydrocannabinol: Δ9-Tetrahydrocannabiphorol

(-)-Trans-Δ9-tetrahydrocannabinol (Δ9-THC) is the main compound responsible for the intoxicant activity of Cannabis sativa L. The length of the side alkyl chain influences the biological activity of this cannabinoid. In particular, synthetic analogues of Δ9-THC with a longer side chain have shown cannabimimetic properties far higher than Δ9-THC itself. In the attempt to define the phytocannabinoids profile that characterizes a medicinal cannabis variety, a new phytocannabinoid with the same structure of Δ9-THC but with a seven-term alkyl side chain was identified. The natural compound was isolated and fully characterized and its stereochemical configuration was assigned by match with the same compound obtained by a stereoselective synthesis. This new phytocannabinoid has been called (-)-trans-Δ9-tetrahydrocannabiphorol (Δ9-THCP). Along with Δ9-THCP, the corresponding cannabidiol (CBD) homolog with seven-term side alkyl chain (CBDP) was also isolated and unambiguously identified by match with its synthetic counterpart. The binding activity of Δ9-THCP against human CB1 receptor in vitro (Ki = 1.2 nM) resulted similar to that of CP55940 (Ki = 0.9 nM), a potent full CB1 agonist. In the cannabinoid tetrad pharmacological test, Δ9-THCP induced hypomotility, analgesia, catalepsy and decreased rectal temperature indicating a THC-like cannabimimetic activity. The presence of this new phytocannabinoid could account for the pharmacological properties of some cannabis varieties difficult to explain by the presence of the sole Δ9-THC.

Synthetic Strategies for (-)-Cannabidiol and Its Structural Analogs

(-)-Cannabidiol ((-)-CBD), a non-psychoactive phytocannabinoid from Cannabis, and its structural analogs have received growing attention in recent years because of their potential therapeutic benefits, including neuroprotective, anti-epileptic, anti-inflammatory, anxiolytic, and anti-cancer properties. (-)-CBD and its analogs have been obtained mainly based on extraction from the natural source; however, the conventional extraction-based methods have some drawbacks, such as poor quality control along with purification difficulty. Chemical-synthetic strategies for (-)-CBD could tackle these issues, and, additionally, generate novel (-)-CBD analogs that exhibit advanced biological activities. This review concisely summarizes the historic and recent milestones in the synthetic strategies for (-)-CBD and its analogs.