Mini Reviews in Medicinal Chemistry - Volume 17, Issue 1, 2017

G-protein coupled receptors (GPCRs) represent important targets for drug discovery because they participate in a wide range of cellular signalling pathways that play a role in a variety of pathological conditions. The characterization of the patho-physiological profile and functional roles of new receptors is highly dependent on the availability of potent and selective ligands and new screening assays. The study of the pharmacological profile of new chemical entities is very important in order to predict the activity of drugs and their clinical adverse effect in humans. In the last decade, a large number of new in vitro radiolabel-free assays were developed and relevant information on diseases was upgraded. In particular, radiolabel-free assays led significant easy to handle and safer tools for operators. The aim of this review is to analyze these assays in terms of new drug activity and toxicology prediction and translation of non-clinical findings to humans in order to provide a powerful tool to aid drug development.

Glycine is the smallest non-essential, neutral and metabolically inert amino acid, with a carbon atom bound to two hydrogen atoms, and to an amino and a carboxyl group. This amino acid is an essential substrate for the synthesis of several biologically important biomolecules and compounds. It participates in the synthesis of proteins, of the tripeptide glutathione and in detoxification reactions. It has a broad spectrum of anti-inflammatory, cytoprotective and immunomodulatory properties. To exert its actions, glycine binds to different receptors. The GlyR anion channel is the most studied receptor for glycine. However, there are GlyR-independent mechanisms for glycine cytoprotection and other possible binding molecules of glycine are the NMDA receptor and receptors GlyT1 and GlyT2. Although, in humans, the normal serum level of glycine is approximately 300 μM, increasing glycine intake can lead to blood levels of more than 900 μM that increase its benefic actions without having harmful side effects. The herbal pesticide glyphosate might disrupt glycine homeostasis. Many in vitro studies involving different cell types have demonstrated beneficial effects of the addition of glycine. Glycine also improved conditions of isolated perfused or stored organs. In vivo studies in experimental animals have also tested glycine as a protector molecule and some studies on the beneficial effects of glycine after its clinical application have been done. Although at high-doses, glycine may cause toxic effects, further studies are needed to investigate the safe range of usage of this aminoacid and to test the diverse routes of administration.

Cinnamaldehyde analogues are a class of chemical substances originated from derivatization of cinnamaldehyde, and are structurally characterized by the presence of cinnamoyl moiety. Due to the presence of highly reactive α,α-unsaturated carbonyl pharmacophore (Michael acceptor) in their structures, these molecules are apt to react with some enzymes and/or receptors as electrophiles, and consequently produce diverse therapeutically relevant pharmacological functions. Naturally occurring molecules, trans-cinnamaldehyde (CA), 2-benzoyloxycinnam-aldehyde (2-BCA), and 2- hydroxycinnamaldehyde (2-HCA) are representatives of this group, and have attracted lots of interest for their bioactivities, especially the anti-cancer and anti-inflammatory properties. Owing to the potential of CA, 2-BCA, and 2-HCA as therapeutic agents, researches on chemical syntheses and modifications have been carried out to gain chemical entities with potent bioactivity and favorable druggability. This review summarizes the progress on phytochemical and pharmacological aspects of natural cinnamaldehyde analogues, illustrate the representative of synthetic molecules with potent bioactivity, and discuss their potential as therapeutic agents.

Introduction: The anthracycline doxorubicin (DOX) has proved to be one of the most widely used and most effective antitumor drugs since its emergence in the 1960s. However, the utility of DOX is compromised by its potential lethal cardiotoxicity. In this review we summarize development in prevention and management of DOX-induced cardiotoxicity comprehensively. Background: Strategies to enhance DOX efficacy in cancer cells while minimizing associated cardiotoxicity may prove clinically valuable. Employment of DOX derivatives, including currently available mitoxantrone and epirubicin, has been testified in several clinical trials. Several cardioprotective agents, including dexrazoxane, statins, angiotensin-converting enzyme inhibitors, calcium channel blockers, beta-blockers, and etc., have been developed and tested in animal and clinical trials. Conclusion: Several strategies have been reported on the prevention and management of DOX-elicited cardiotoxicity, and many of them await verification from large scale clinical trials. Dexrazoxane has been approved to prevent and treat side effects of DOX, although concerns still exist that it might increase incidence of some kind of malignant tumors. Promising findings in autophagy, RNA binding protein quaking and statins encourage further research developing strategies by which heart protection and cancer cell killing are achieved simutaneously.

Obesity is growing at an alarming rate with huge consequences on health and economy. The worldwide prevalence of obesity has nearly doubled in less than 35 years. Obesity causes many physiological dysfunctions that affect nearly every organ producing multiple morbidities. Despite these facts, there is still no clear, well-defined solution. Notwithstanding the devastating prevalence and consequences of obesity, today only five medicines, orlistat, lorcaserin, phentermine-topiramate, bupropion-naltrexone and liraglutide, are approved by the FDA for long-term treatment of obesity. In this review, the current approaches to treat obesity such as the development of diacylglycerol Oacyltransferase- 1 inhibitors, growth hormone secretagogue receptor-1a antagonists/inverse agonists, melanocortin-3 receptors agonists and melanin concentrating hormone receptor-1 antagonists, will be discussed. The main focus will be on the molecules that were able to reach clinical trials. The last section is dedicated to the “browning” phenomenon of white adipose tissues and the potential of Aldh1a1 inhibitors to treat obesity.

Gentiopicroside is a secoiridoid compound isolated from Gentiana lutea which is called Qin Jiao in Chinese. It is one of the most common herbal medicines used in China. In this article, we review the pharmacological and biological activity (antiviral, anti-inflammatory, analgesia, antihepatotoxic and choleretic), as well as biotransformation of the gentiopicroside. In addition, attempt towards the total synthesis of gentiopicroside is also presented.

Background: Phencyclidine (PCP) as well as the analogues has indicated several pharmacological behaviors like analgesic, anticonvulsant, antianxiety, antidepressant depending on the dose and species examined. They interact with some neurotransmitter systems in the central nervous system like particular affinity for PCP sites in NMDA receptors or dopamine uptake blocking or both. Objective: Due to analgesic properties of aminobenzothiazoles family, piperidine ring of PCP was replaced with electron-donating and electron-withdrawing substituted aminobenzothiazoles (1-4) for obtaining new analogues (II-V) with more analgesic activities. Methods: Synthesis of new compounds (II-V) and measuring the acute and chronic pain properties of them were carried out through applying tail immersion tests on mice and the outcomes compared with control & PCP groups at dosage of 10 mg/kg. Results: III & V with substituted methoxy and methyl-aminobenzothiazoles indicated better activity to lessen acute and chronic (thermal and chemical) pains compared with unsubstituted & phencyclidine animal groups. Conclusion: Methoxy and methyl-aminobenzothiazole derivatives” of phencyclidine revealed more analgesic activities compared with other groups which may concern to close affinity for DA uptake blocking as well as NMDA receptors in this family.