Current Topics in Medicinal Chemistry - Volume 17, Issue 4, 2017

Background: The present study was designed to evaluate the anti-hyperalgesic effect of kaempferol-3,7-di-O-α-L-rhamnopyranoside isolated from the ethyl acetate soluble part of Dryopteris cycadina. Pretreatment of the compound at the doses of 2.5, 5, and 10 mg/kg caused a significant reduction in abdominal constrictions in acetic acid-induced writhing test with maximum effect of 63.03% (P < 0.001) at 10 mg/kg i.p. When subjected in formalin test, it evoked a marked antinociceptive effect in both phases in a dose-dependent manner. The maximum (p < 0.01) pain-inhibiting effects were 61.36% and 65.89% in 1st and 2nd phases at 10 mg/kg i.p., respectively. Administration of atropine (non-selective cholinergic receptor antagonist) significantly (p < 0.05) antagonized the antihyperalgesic effect of the compound, while glibenclamide and naloxone did not alter the induced antinociceptive effect and thus, antinociceptive activity of the compound is mediated, at least in part, through cholinergic system antagonism; independent of calcium channel and opioidergic receptor participation. Furthermore, docking studies underlined strong COX-2 inhibitory activity of the compound. Result: Our data concluded that overall analgesic activity of the compound seems to involve COX-2 inhibition and activation of cholinergic receptors. However, further detailed studies are required in this direction to confirm the analgesic effect of the compound for its possible clinical utility.

Cardiovascular disease is the main cause of death in the developed countries. Dyslipidaemia is one of the risk factors associated to cardiovascular disease and it is characterised by abnormal amounts of lipids (i.e. cholesterol and fatty acids) and/or circulating lipoproteins in the blood. Oxidative stress has been implicated in the pathogenesis of various illnesses including cardiovascular disease. In this way, the potential therapeutic or preventive effects of antioxidant mediators have recently drawn much attention. Coumarin (1,2-benzopyrone) is a natural phenolic compound found in many plants such as citrus fruits, tomatoes, vegetables and green tea. Coumarin and derivates are proposed as lipid lowering agents due to its broad pharmacological activities, mainly the implicated in vasodilator and antioxidant effect. Several studies have evidenced a promising role of coumarin and several of its derivates as lipid lowering agents. In the current work, the available reports related to the promising function of these compounds are reviewed.

Background: Trypanosoma cruzi is the causative agent of Chagas disease. This parasite is vulnerable to the effects of ROS as its main defense mechanism against exogenous agents trypanothione is also another weakness of the parasite that investigated related to the inhibition of enzymes belonging P450 system, mainly CYP51. In our group we have synthesized a series of triazoles known as [1,2,3]triazolo[1,5-a]pyridyl ketones, and pyridyl ketones. These families have shown interesting structural features due to the presence of electron withdrawing moieties attached to the main heterocycle (triazoles and/or pyridines) and are proposed as potential target in the parasite, by the presence of the carbonyl group being able to be reduced and form a free radical that could interact with molecular oxygen generating ROS in the parasite. Furthermore, the triazole ring and pyridines have been considered as potent inhibitors of sterol biosynthesis, the lock being part CYP51. Result: Our results showed that the series is capable of generating a stable radical species and generate ROS in the parasite. On the other hand these molecules are potent inhibitors of enzymes belonging to the complex P450. We have focused on the inhibition of ergosterol biosynthesis demonstrating that triazole/ pyridine families are able to affect this pathway being observed the accumulation of squalene and lanosterol.

Background: Polyphenols are organic compounds widely found in plants and possess many diverse biological activities. In the current study, eleven polyphenolic compounds [rutin (1), trans-ferulic acid (2), epigallaocatechin gallate (3), fumaric acid (4), chlorogenic acid (5), gallic acid (6), trans-resveratrol (7), propyl gallate (8), (+)-catechin (9), quercetin (10), and kaempferol-3-O-β-D-galactoside (11)] have been evaluated for their in vitro inhibitory activity against phosphodiesterase- 1 (PDE-1). The active compounds 1, 5, 6, and 7 possessed IC50 values of 173.90 ± 2.58, 36.67 ± 1.60, 325.19 ± 3.62, and 323.81 ± 4.25 μM, respectively. In silico experiments were performed to elucidate the binding patterns of inhibitor molecules with the active sites of the enzymes. Result: Molecular docking studies have shown that compounds 1 and 5 have better docking results than standard inhibitor (EDTA) against the PDE-1. In conclusion, chlorogenic acid, rutin, gallic acid, and resveratrol could be promising PDE-1 inhibitors and leads to identify new drug candidates against PDE-1-associated disorders.

Amaryllidaceae alkaloids (AAs), which are natural heterocyclic compounds, are isolated from Amaryllidaceae plants such as narcissus, snowdrop and spider lily. AAs have been extensively studied due to their multiple pharmacological properties. Nevertheless, knowledge of AA synthesis in plants is lacking and most genes encoding enzymes involved in their production remain unknown. AAs are structurally complex compounds which are challenging for total chemical synthesis that is economically viable. Therefore the understanding of AA biosynthesis could allow for the development of biotechnologies for the production of natural AAs or analogues, maintaining or improving their pharmacological properties. In this review, we describe the progress regarding the biosynthesis and pharmacological properties of AAs. The most recent developments in neurological, anti-cancer and anti-microbial bioactivities of heterocyclic AAs are covered.

Diabetes Mellitus (DM) is a metabolic disease characterized by high blood sugar levels. Recently, it has emerged as an important and global health problem with long-term complications and high economic burden. α-Amylase (α-Amy) and α-glucosidase (α-Gls) are two enzymes which are involved in the hydrolysis of starch into sugars and disaccharides leading to the increase of blood glucose level. Hence, inhibition of α-amylase and α-glucosidase plays key role in the treatment of type 2 diabetes. Heterocyclic compounds -both synthetic and naturally occurring derivatives- possess efficient biological properties. At this juncture, they have demonstrated potent inhibitory activity against α-Amy and α-Gls and were found to be versatile tools for the development of novel anti-diabetic agents.

Background: Synthesis, computational study and biological evaluation of peptidomimetic analogues of FR235222 (3), a natural immunosuppressant and HDAC inhibitor, have been reported. These new compounds, bearing α-hydroxyketone moiety, as more stable zinc binding group (ZBG), were evaluated in vitro as HDAC inhibitors against the human HDACs isoforms 1-9 and in cellular antiproliferative assays on U937 human leukemia cell line. The 1,4-benzodiazepin-2,5-dione (BDZ), capping group and the natural ZBG, (S,R)-2-amino-9-hydroxy-8-oxodecanoic acid (Ahoda), were evaluated in order to probe HDAC inhibition and/or paralogue selectivity. Some of the new derivatives showed an interesting activity against a number of HDAC isozymes. The observed activity profile was rationalized by a computational assisted SAR study, in order to understand how the BDZ classes interact with the enzyme into the catalytic pocket. Despite its poor solubility, compound 17b showed significant antiproliferative profile and HDAC inhibition activity. Result: In order to assess how the solubility issue could have affected the biological outcome, bioassay conditions were reproduced and quantification of precipitated particulate material was evaluated by turbidimetric and NMR studies together with physicochemical descriptors prediction. Thus, BDZ 17b has been chosen to be promising lead compounds for further optimization, in order to elucidate molecule- enzyme surface recognition.

Chagas disease is one of the major health problems in Central and South America, which is caused by the parasitic protozoa, Trypanosoma cruzi. It is commonly transmitted by members of blood-sucking subfamily Triatominae. Chagas disease is associated with cardiac and gastrointestinal manifestations. Up to now, there are no effective vaccines for treatment of Chagas disease and benznidazole and nifurtimox are the only effective anti-Chagas drugs that cause different adverse and side effects. Therefore, much attention has been paid to natural products as novel therapeutic strategies for Chagas disease and its manifestations. Nowadays, some flavonoids could be considered as effective and safe bioactive natural products with potential anti-Chagas activity. Despite the increasing evidence, there is lack of review papers regarding the beneficial effects of flavonoids against Chagas disease and its manifestations. The aim of this paper is to review the available scientific data on the beneficial effects of flavonoids on Chagas disease and its manifestations published over the past two decades. Moreover, we provide an overview on etiology, transmission, epidemiology, clinical manifestations, and current treatment protocols of Chagas disease.

Melatonin is an indoleamine with potent multifunctional biological and pharmacological effects, both receptor dependent and receptor-independent effects, including antioxidant, anticancer, antitumor, anti-inflammatory, anti-aging, anti-diabetic, antiviral, neuroprotective activities. Melatonin mitigates tissue injury via modification of abnormalities in redox status and other biochemical markers. At the molecular level, the biological and pharmacological activities of melatonin are attributed to the inhibition of nuclear factor-Κappa beta (NF-Κβ), c-Fos over expression and down-regulation of matrix metalloproteinases-3 (MMP-3), which are regulators of pro-inflammatory and pro-fibrotic cytokines. There are numerous scientific reports on the therapeutic potential of melatonin in treatment of asthma, respiratory diseases for infections, chronic obstructive pulmonary disease, lung cancer, pleural cavity diseases, as well as vascular pulmonary disease. In the present communication, we systematically review the therapeutic potential of melatonin in the treatment of respiratory diseases along with its molecular mechanism of actions.

Background: A series of perimidinone derivatives (7H-benzo[e]perimidin-7-one) were synthesized and assessed by means of in vitro assays as human MAO inhibitors. These compounds inhibited reversibly the enzymes with inhibitory constants in the range of 2 to 20 μM. In addition, the selectivity of inhibition of the MAO isoforms seems to be significantly dependent of the presence either of heteroatom or electron donating and withdrawing groups on the perimidinone framework, which was verified by using molecular docking simulation with the crystallized MAO receptors. Most of these inhibitors were highly selective: 9 and 11 inhibited selectively the MAO-B isoform while 12 had 10-fold selectivity for MAO-A isoform. Moreover, the compound 12 was both the most selective and potent MAO-A inhibitor among perimidinones. Result: These results have important implications for the drug design of molecules targeting depression and movement-related disorders.

Background: A new variety of adamantyl chalcones (2, 3a-o) were efficiently prepared by Claisen-Schmidt reaction of 4-adamantyl acetophenone 2 with a serie of aromatic aldehydes in good yields. Their structures were confirmed by spectroscopic data, and the relative configuration of 3d was confirmed by X-ray crystallography. All synthesized chalcones were tested against a panel of Grampositive and Gram-negative bacteria and pathogenic fungus and displayed strong antibacterial activity against Enterococcus faecali 29212, Pseudomonas aeruginosa ATCC27853, Escherichia coli and interesting antifungal activity against Candida glabrata ATCC 90030. Result: The effect of these compounds was also tested in vitro as antitumor on Miapaca2 cells. Compounds also showed anticancer activity against human pancreas cancer cell MiaPaca2.