Desmond Slade

Potency Trends of Δ9‐THC and Other Cannabinoids in Confiscated Cannabis Preparations from 1993 to 2008*

Abstract:  The University of Mississippi has a contract with the National Institute on Drug Abuse (NIDA) to carry out a variety of research activities dealing with cannabis, including the Potency Monitoring (PM) program, which provides analytical potency data on cannabis preparations confiscated in the United States. This report provides data on 46,211 samples seized and analyzed by gas chromatography‐flame ionization detection (GC‐FID) during 1993–2008. The data showed an upward trend in the mean Δ9‐tetrahydrocannabinol (Δ9‐THC) content of all confiscated cannabis preparations, which increased from 3.4% in 1993 to 8.8% in 2008. Hashish potencies did not increase consistently during this period; however, the mean yearly potency varied from 2.5–9.2% (1993–2003) to 12.0–29.3% (2004–2008). Hash oil potencies also varied considerably during this period (16.8 ± 16.3%). The increase in cannabis preparation potency is mainly due to the increase in the potency of nondomestic versus domestic samples.

Antidepressant-like effect of Δ9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L.

The antidepressant action of cannabis as well as the interaction between antidepressants and the endocannabinoid system has been reported. This study was conducted to assess the antidepressant-like activity of Delta(9)-THC and other cannabinoids. Cannabinoids were initially evaluated in the mouse tetrad assay to determine doses that do not induce hypothermia or catalepsy. The automated mouse forced swim (FST) and tail suspension (TST) tests were used to determine antidepressant action. At doses lacking hypothermic and cataleptic effects (1.25, 2.5, and 5 mg/kg, i.p.), both Delta(9)-THC and Delta(8)-THC showed a U-shaped dose response with only Delta(9)-THC showing significant antidepressant-like effects at 2.5 mg/kg (p<0.05) in the FST. The cannabinoids cannabigerol (CBG) and cannabinol (CBN) did not produce antidepressant-like actions up to 80 mg/kg in the mouse FST, while cannabichromene (CBC) and cannabidiol (CBD) exhibited significant effect at 20 and 200mg/kg, respectively (p<0.01). The antidepressant-like action of Delta(9)-THC and CBC was further confirmed in the TST. Delta(9)-THC exhibited the same U-shaped dose response with significant antidepressant-like action at 2.5 mg/kg (p<0.05) while CBC resulted in a significant dose-dependent decrease in immobility at 40 and 80 mg/kg doses (p<0.01). Results of this study show that Delta(9)-THC and other cannabinoids exert antidepressant-like actions, and thus may contribute to the overall mood-elevating properties of cannabis.

Cannabinoid ester constituents from high-potency Cannabis sativa.

Eleven new cannabinoid esters, together with three known cannabinoid acids and Delta9-tetrahydrocannabinol ( Delta9-THC ), were isolated from a high-potency variety of Cannabis sativa. The structures were determined by extensive spectroscopic analyses to be beta-fenchyl Delta9-tetrahydrocannabinolate ( 1), epi-bornyl Delta9-tetrahydrocannabinolate ( 2), alpha-terpenyl Delta9-tetrahydrocannabinolate ( 3), 4-terpenyl Delta 9-tetrahydrocannabinolate ( 4), alpha-cadinyl Delta9-tetrahydrocannabinolate ( 5), gamma-eudesmyl Delta9-tetrahydrocannabinolate ( 6), gamma-eudesmyl cannabigerolate ( 7), 4-terpenyl cannabinolate ( 8), bornyl Delta9-tetrahydrocannabinolate ( 9), alpha-fenchyl Delta9-tetrahydrocannabinolate ( 10), alpha-cadinyl cannabigerolate ( 11), Delta9-tetrahydrocannabinol ( Delta9-THC ), Delta9-tetrahydrocannabinolic acid A ( Delta9-THCA ), cannabinolic acid A ( CBNA), and cannabigerolic acid ( CBGA). Compound 8 showed moderate antimicrobial activity against Candida albicans ATCC 90028 with an IC 50 value of 8.5 microg/mL. The isolated acids and the ester-containing fractions showed low affinity to the CB-1 receptor. [corrected]

Artemisinin dimer anticancer activity correlates with heme-catalyzed reactive oxygen species generation and endoplasmic reticulum stress induction.

Analogs of the malaria therapeutic, artemisinin, possess in vitro and in vivo anticancer activity. In this study, two dimeric artemisinins (NSC724910 and 735847) were studied to determine their mechanism of action. Dimers were >1,000 fold more active than monomer and treatment was associated with increased reactive oxygen species (ROS) and apoptosis induction. Dimer activity was inhibited by the antioxidant L‐NAC, the iron chelator desferroxamine and exogenous hemin. Similarly, induction of heme oxygenase (HMOX) with CoPPIX inhibited activity, whereas inhibition of HMOX with SnPPIX enhanced it. These results emphasize the importance of iron, heme and ROS in activity. Microarray analysis of dimer treated cells identified DNA damage, iron/heme and cysteine/methionine metabolism, antioxidant response, and endoplasmic reticulum (ER) stress as affected pathways. Detection of an ER‐stress response was relevant because in malaria, artemisinin inhibits pfATP6, the plasmodium orthologue of mammalian sarcoplasmic/endoplasmic reticulum Ca2+‐ATPases (SERCA). A comparative study of NSC735847 with thapsigargin, a specific SERCA inhibitor and ER‐stress inducer showed similar behavior in terms of transcriptomic changes, induction of endogenous SERCA and ER calcium mobilization. However, thapsigargin had little effect on ROS production, modulated different ER‐stress proteins and had greater potency against purified SERCA1. Furthermore, an inactive derivative of NSC735847 that lacked the endoperoxide had identical inhibitory activity against purified SERCA1, suggesting that direct inhibition of SERCA has little inference on overall cytotoxicity. In summary, these data implicate indirect ER‐stress induction as a central mechanism of artemisinin dimer activity.

Synthesis and evaluation of dihydroartemisinin and dihydroartemisitene acetal dimers showing anticancer and antiprotozoal activity.

Twelve artemisinin acetal dimers were synthesized and tested for antitumor activity in the National Cancer Institute (NCI) in vitro human tumor 60 cell line assay, producing a mean GI(50) concentration between 8.7 (least active) and 0.019 microM (most active). The significant activity of the compounds in this preliminary screen led to additional in vitro antitumor and antiangiogenesis studies. Several active dimers were also evaluated in the in vivo NCI hollow fiber assay followed by a preliminary xenograft study. The title compounds were found to be active against solid tumor-derived cell lines and showed good correlation with other artemisinin-based molecules in the NCI database. The dimers were also evaluated for their antimalarial and antileishmanial activities. The antimalarial activity ranged from 0.3 to 32 nM (IC(50)), compared to 9.9 nM for artemisinin.

Antiprotozoal, anticancer and antimicrobial activities of dihydroartemisinin acetal dimers and monomers

Nine dihydroartemisinin acetal dimers (6-14) with diversely functionalized linker units were synthesized and tested for in vitro antiprotozoal, anticancer and antimicrobial activity. Compounds 6, 7 and 11 [IC(50): 3.0-6.7 nM (D6) and 4.2-5.9 nM (W2)] were appreciably more active than artemisinin (1) [IC(50): 32.9 nM (D6) and 42.5 nM (W2)] against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of the malaria parasite, Plasmodium falciparum. Compounds 10, 13 and 14 displayed enhanced anticancer activity in a number of cell lines compared to the control drug, doxorubicin. The antifungal activity of 7 and 12 against Cryptococcus neoformans (IC(50): 0.16 and 0.55 microM, respectively) was also higher compared to the control drug, amphotericin B. The antileishmanial and antibacterial activities were marginal. A number of dihydroartemisinin acetal monomers (15-17) and a trimer (18) were isolated as byproducts from the dimer synthesis and were also tested for biological activity.

Naturally Occurring and Related Synthetic Cannabinoids and their Potential Therapeutic Applications

Naturally occurring cannabinoids (phytocannabinoids) are biosynthetically related terpenophenolic compounds uniquely produced by the highly variable plant, Cannabis sativa L. Natural and synthetic cannabinoids have been extensively studied since the discovery that the psychotropic effects of cannabis are mainly due to Delta(9)-THC. However, cannabinoids exert pharmacological actions on other biological systems such as the cardiovascular, immune and endocrine systems. Most of these effects have been attributed to the ability of these compounds to interact with the cannabinoid CB1 and CB2 receptors. The FDA approval of Marinol, a product containing synthetic Delta(9)-THC (dronabinol), in 1985 for the control of nausea and vomiting in cancer patients receiving chemotherapy, and in 1992 as an appetite stimulant for AIDS patients, has further intensified the research interest in these compounds. This article reviews patents (2003-2007) that describe methods for isolation of cannabinoids from cannabis, chemical and chromatographic methods for their purification, synthesis, and potential therapeutic applications of these compounds.

Phytochemistry of the mopane, Colophospermum mopane.

The polyphenolic pool of the heartwood of the mopane, Colophospermum mopane Kirk ex J. Leonard, exhibits extreme diversity and complexity. It comprises a variety of monomeric flavonoids, e.g. flavan-3-ols, flavan-3,4-diols including the mopanols and peltogynols, flavonols, dimeric proanthocyanidins, e.g. proguibourtinidins, profisetinidins, promopanidins, propeltogynidins, and a variety of profisetinidin-type triflavanoids. The di- and tri-meric proanthocyanidins are accompanied by several functionalized tetrahydropyrano- and hexahydrodipyrano-chromenes (phlobatannins) that originate from the bi- and tri-flavanoids, respectively, via rearrangement of the pyran heterocycle(s). Owing to the predominance of the 5-deoxy (A-ring) flavan-3-ols, the chain terminating moieties in the biosynthesis of oligo- and poly-meric proanthocyanidins, the di- and tri-meric analogs also exhibit diversity as far as interflavanyl bonding positions are concerned. Such heterogeneity results from the reduced nucleophilicity of the A-rings of 5-deoxy flavan-3-ols, compared to the A-rings of the 5-oxy analogs (catechins), hence permitting alternative centers to participate in proanthocyanidin formation. Biomimetic-type syntheses were extensively utilized to unequivocally establish constitution and absolute stereochemistry of both the conventional and pyran ring rearranged-type di- and tri-meric compounds. Comprehension of the intricate mechanistic and stereochemical course of the pyran ring rearrangement reactions also contributed significantly to unambiguous structure elucidations. The aerial parts of the mopane are rich in essential oils that comprise mainly alpha-pinene and limonene, which are presumably responsible for the strong turpentine odor of the pods. The leaves also contain significant concentrations of beta-sitosterol and stigmasterol which are apparently the source of sterols in various organs of the mopane moth, Gonimbrasia belina. Three diterpenes, dihydrogrindelic acid, labd-13E-en-15-oate and dihydrogrindelaldehyde are present in the bark and seeds, the latter compound exhibiting significant cytotoxicity against a human breast cancer cell line.

Isolation and Pharmacological Evaluation of Minor Cannabinoids from High-Potency Cannabis sativa

Seven new naturally occurring hydroxylated cannabinoids (1-7), along with the known cannabiripsol (8), have been isolated from the aerial parts of high-potency Cannabis sativa. The structures of the new compounds were determined by 1D and 2D NMR spectroscopic analysis, GC-MS, and HRESIMS as 8α-hydroxy-Δ(9)-tetrahydrocannabinol (1), 8β-hydroxy-Δ(9)-tetrahydrocannabinol (2), 10α-hydroxy-Δ(8)-tetrahydrocannabinol (3), 10β-hydroxy-Δ(8)-tetrahydrocannabinol (4), 10α-hydroxy-Δ(9,11)-hexahydrocannabinol (5), 9β,10β-epoxyhexahydrocannabinol (6), and 11-acetoxy-Δ(9)-tetrahydrocannabinolic acid A (7). The binding affinity of isolated compounds 1-8, Δ(9)-tetrahydrocannabinol, and Δ(8)-tetrahydrocannabinol toward CB1 and CB2 receptors as well as their behavioral effects in a mouse tetrad assay were studied. The results indicated that compound 3, with the highest affinity to the CB1 receptors, exerted the most potent cannabimimetic-like actions in the tetrad assay, while compound 4 showed partial cannabimimetic actions. Compound 2, on the other hand, displayed a dose-dependent hypolocomotive effect only.

Evaluation of phytocannabinoids from high-potency Cannabis sativa using in vitro bioassays to determine structure–activity relationships for cannabinoid receptor 1 and cannabinoid receptor 2

Cannabis has been around for thousands of years and has been used recreationally, medicinally, and for fiber. Over 500 compounds have been isolated from Cannabis sativa with approximately 105 being cannabinoids. Of those 105 compounds, Δ9-tetrahydrocannabinol has been determined as the primary constituent, which is also responsible for the psychoactivity associated with Cannabis. Cannabinoid receptors belong to the large superfamily of G protein-coupled receptors. Targeting the cannabinoid receptors has the potential to treat a variety of conditions such as pain, neurodegeneration, appetite, immune function, anxiety, cancer, and others. Developing in vitro bioassays to determine binding and functional activity of compounds has the ability to lead researchers to develop a safe and effective drug that may target the cannabinoid receptors. Using radioligand binding and functional bioassays, a structure–activity relationship for major and minor cannabinoids was developed.