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CRA13; a peripheral dual CB1R/CB2R agonist with clinically proven analgesic properties, infiltrates into CNS producing adverse effects due to central CB1R agonism. Such adverse effects might be circumvented by less lipophilic compounds with attenuated CB1R affinity. Metabolism produces less lipophilic metabolites that might be active metabolites. Some CRA13 oxidative metabolites and their analogues were synthesized as less lipophilic CRA13 analogues. Probing their CB1R and CB2R activity revealed the alcohol metabolite 8c as a more potent and more effective CB2R ligand with attenuated CB1R affinity relative to CRA13. Also, the alcohol analogue 8b and methyl ester 12a possessed enhanced CB2R affinity and reduced CB1R affinity. The CB2R binding affinity of alcohol analogue 8b was similar to CRA13 while that of methyl ester 12a was more potent. In silico study provided insights into the possible molecular interactions that might explain the difference in the elicited biological activity of these compounds.

In recent years, there has been a marked increase in the use of recreational synthetic psychoactive substances, which is a cause of concern among healthcare providers and legal authorities. In particular, there have been reports on the misuse of 5-(2-aminopropyl)indole (5-API; 5-IT), a new synthetic drug, and of fatal and non-fatal intoxication. Despite these reports, little is known about its psychopharmacological effects and abuse potential. Here, we investigated the abuse potential of 5-IT by evaluating its rewarding and reinforcing effects through conditioned place preference (CPP) (1, 10, and 30 mg/kg, i.p.) in mice and self-administration test (0.1, 0.3, 1, and 3 mg/kg/inf., i.v.) in rats. We also examined whether 5-IT (1, 3, and 10 mg/kg, i.p.) induces locomotor sensitization in mice following a 7-day treatment and drug challenge. Then, we explored the effects of 5-IT (10 mg/kg, i.p.) on dopamine-related genes in the striatum, prefrontal cortex (PFC), and substantia nigra pars compacta (SNc)/ventral tegmental (VTA) of mice by quantitative real-time polymerase chain reaction. 5-IT produced CPP in mice but was not reliably self-administered by rats. 5-IT also induced locomotor sensitization following repeated administration and drug challenge. Moreover, 5-IT increased mRNA levels of dopamine D1 receptor in the striatum and PFC and dopamine transporter in the SNc/VTA of mice. These results indicate that 5-IT has psychostimulant and rewarding properties, which may be attributed to its ability to affect the dopaminergic system in the brain. These findings suggest that 5-IT poses a substantial risk for abuse and addiction in humans.

Cancer still represents a major global health problem. All currently available anticancer agents have disadvantages like resistance or side effects. Therefore, introduction of novel anticancer agents is needed. Intrigued by the high success rate for natural products-based drug discovery, we designed and synthesized antiproliferative chemical entities as hybrids of two natural products; 3,5,4′-trimethoxystilbene and 5,6,7-trimethoxyflavone. To probe the spectrum of the synthesized compounds, in vitro evaluation was conducted against nine panels representing major cancer diseases. The results revealed the hybrid analogs 4f, 4h, 4k and 4q as promising broad-spectrum anticancer lead compounds eliciting high growth inhibition of several cell lines representing multiple cancers diseases. Evaluation of the promising lead compounds against normal human cell lines suggested a selective cytotoxic effect on cancer cells. Mechanistic investigation of the cytotoxic activity of compound 4f in human cervical cancer HeLa cells showed that it triggers cell death through induction of apoptosis. As a whole, this study presents the natural products hybrid analogs 4f, 4h, 4k and 4q as potential lead compounds for further development of novel anticancer therapeutics.

CRA13; a peripheral dual CB

Two series of erlotinib-alkylphospholipid hybrids were prepared and evaluated for their antiproliferative activities against a panel of four cell lines representing lung, breast, liver and skin cancers using erlotinib and miltefosine as reference standards. Amide analogs elicited more enhanced cytotoxic activity than analogous esters. Amide derivatives 8d and 8e exhibited promising broad-spectrum antiproliferative activity and higher efficacy than reference erlotinib and miltefosine. Their cellular GI50 values was in the ranges of 24.7–46.9 μM and 26.8–43.1 μM for 8e and 8d respectively. Assay results of the inhibitory activity of the prepared compounds on EGFR kinase reaction and Akt phosphorylation in conjugation with statistical correlation analysis indicated that other mechanisms might contribute to their elicited cytotoxicities. In addition, statistical correlation analysis revealed that mechanisms of elicited cytotoxicities for amide series might be different from ester series. In addition, correlation analysis indicated variations in the mechanisms according to the types of cell line.

5-Methoxy-α-methyltryptamine (5-MeO-AMT) is a tryptamine derivative that is used recreationally because of its reported hallucinogenic and mood elevating effects. Studies suggest that the psychopharmacological effects of tryptamines involve serotonin receptor 2a (5-HTR2a) activation in the brain. The head-twitch response (HTR) is widely used as a behavioral correlate for assessing 5-HTR2a agonist activity of a drug. Thus, we investigated whether 5-MeO-AMT induces HTR in mice and explored its mechanism of action. 5-MeO-AMT (0.3, 1, 3, 10 mg/kg) was administered once a day for 7 days, and the HTR was measured after 1 day (acute) and 7 days (repeated) of administration. Another cohort of mice was treated with 5-HTR2a antagonist ketanserin (KS) before 5-MeO-AMT administration. We measured 5-HTR2a and 5-HTR2c mRNA levels in the prefrontal cortex of the mice treated acutely or repeatedly with 5-MeO-AMT. We performed western blotting to determine the effects of the drug on the expression of G protein (Gq/11), protein kinase C gamma (PKC-γ), and extracellular signal-regulated kinases 1/2 (ERK1/2), in addition to PKC-γ and ERK1/2 phosphorylation. Additionally, we evaluated potential rewarding and reinforcing effects of 5-MeO-AMT using locomotor sensitization, conditioned place preference (CPP), and self-administration (SA) paradigms. Acute 5-MeO-AMT administration elicited the HTR, while repeated administration resulted in tolerance. KS blocked the 5-MeO-AMT-induced HTR. 5-MeO-AMT increased 5-HTR2a mRNA levels and induced PKC-γ phosphorylation in the prefrontal cortex. 5-MeO-AMT did not induce locomotor sensitization, CPP, or SA. This study shows that 5-MeO-AMT induces HTR through 5-HTR2a activation in the prefrontal cortex, and may have low potential for abuse.