Medicinal Chemistry - Volume 13, Issue 3, 2017

Background: Estrogen receptors (ERs) are an important target for the management of breast cancers. Selective estrogen receptor down-regulators (SERDs) block ER activity, as well as reduce ERα protein levels in cells, and therefore are promising therapeutic agents for the treatment of breast cancers. Objective: In order to develop potent SERDs, we prepared tamoxifen and fulvestrant hybrids and evaluated their binding activity and down-regulation of ERα. Methods: We designed and synthesized tamoxifen derivatives, which had a 4,4,5,5,5- pentafluoropentyl group on the terminal alkyl chain. The oxidation state of the sulfur atom and alkyl length between the sulfur and nitrogen atoms were varied. Western blotting was performed to determine the ability to down-regulate ERα. Binding affinities of synthesized compounds were evaluated by a fluorescence polarization-based competitive binding assay. Results: We successfully prepared nine compounds. Treatment with 11, 14, and 17 effectively reduced ERαprotein levels in MCF-7 cells in a concentration-dependent manner. This reduction was inhibited by a proteasome inhibitor. The ability of 14 to down-regulate the ERαprotein level was equal to fulvestrant. All compounds showed a largely equal affinity for ERα. Conclusion: As indicated by Western blots, the ERαdegradation activity was observed only in the series of butyl linker derivatives, namely, 11, 14, and 17. These findings suggest that the specific length of the alkyl chain is an important factor in controlling the down-regulation of ER. These results provide useful information for designing promising SERD candidates.

Objectives: A series of esters and amides, incorporating an antioxidant residue, such as trolox or caffeic acid, and various moieties with different biological activities, were synthesised. The obtained compounds demonstrated considerable anti-inflammatory, radical scavenging and antioxidant action. Thus, they could reduce carrageenan-induced rat paw oedema by 31-60% at 150 μ mol/kg and inhibit rat microsomal membrane lipid peroxidation with IC50 values as low as 1.4 μ M, which is much lower than that of trolox. Most of them could also inhibit soybean lipoxygenase. The thiomorpholine derivatives decreased significantly all lipidemic indices of Triton-induced hyperlipidemia in rats. The most active, the caffeic acid derivative (6), decreases triglycerides, total cholesterol and low density lipoprotein, in the plasma of hyperlipidemic rats, by 70%, 67%, and 73%, respectively, at 150 μ mol/kg (i.p.). Conclusion: The synthesised compounds, designed to exhibit two or more pharmacological actions, may be considered useful in the study of agents addressed to conditions involving inflammation and oxidative stress.

Background: Indane-1,3-dione, thiazole, bis-thiazole and thiadiazoles rings are very interested moieties in anti-inflammatory and analgesic drugs. Objective: The goal of this work is to synthesize new derivatives of bis-thiazoles and bis-1,3,4- thiadiazoles for the investigation of their anti-inflammatory, anti-ulcerogenic and analgesic activities. Methods: 1,1'-(1,2-phenylene)bis(3-phenylthiourea) (1) reacts with a number of N-aryl arenecarbohydrazonoyl chlorides 2 to give a series of new bis-1,3,4-thiadiazoles 4. Also, reaction of bisthiosemicarbazone of 1,3-indanedione 6 with another type of hydrazonoyl halides namely, N-aryl-2- oxapropanehydrazonoyl chlorides 7 and ethyl-(N-arylhydrazono)chloroacetate 8 in dioxane under reflux in the presence of triethylamine give the respective bis-thiazole derivatives 9 and 10, respectively. The products 9 and 10 can exist in five and seven tautomeric forms for each one. Their actual tautomeric forms were deduced based on electronic absorption data (UV / Vis spectra). Moreover, a series of novel bis-formazans 12 and 13 have been synthesized by reaction of 1,3-dihydrazono-2,3- dihydro-1H-indene (11) with both hydrazonoyl chlorides 7 and 8. Results: The structure of all the novel products was deduced by elemental analysis and spectral data. In addition, the biological activity of the newly synthesized compounds was evaluated and the results obtained indicate their potency as anti-inflammatory, anti-ulcerogenic and analgesic agents. Conclusion: In this context, we synthesize new derivatives of bis-thiazoles and bis-1,3,4-thiadiazoles as anti-inflammatory, anti-ulcerogenic and analgesic agents.

Background: Hyperlipidemia is one of the most common chronic diseases worldwide. Cholesteryl ester transfer protein (CETP) is a hydrophobic glycoprotein that facilitates the transfer of cholesteryl ester from the atheroprotective high-density lipoprotein (HDL) to the proatherogenic low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL). Methods: In this work, synthesis and characterization of five fluorinated 3-benzylamino benzamides 8a-8c, 13a and 13b that target CETP activity were carried out. Results: Benzamides 8b and 8a showed the highest CETP inhibitory activities with an IC50 of 0.75 μ M and 4.1 μ M respectively. It was found that the presence of p-OCF3 group (as in 8a-8c) enhances CETP inhibitory activity more than p-OCF2CHF2 (as in 13a and 13b) which could be attributed to the bulkiness of the tetrafluoroethoxy group hindering their proper orientation in the binding domain. Additionally m-F derivatives were found to have higher activity against CETP than p-F ones leaving the o-F analogues with the weakest anti-CETP bioactivity. Conclusion: Ligand-based and structure-based drug design strategies confirm that hydrophobic interaction mediates ligand/protein complex formation and explains the activity of our verified molecules.

Background: Flavones, are a class of naturally occuring polyphenolic compounds which have 2-phenylchromen-4-one structure. Various studies showed that flavones have several pharmacological activities such as antioxidant, anti-inflammatory, antimicrobial, cytotoxic, antitumour and antiallergic. In the present study, 3-hydroxyflavones also called flavonols, posessing 4'-dialkylamino moiety were synthesized, and their antioxidant and anticholinesterase activities were investigated by comparison with unmodified 3-hydroxflavone. Method: For investigation of antioxidant potential, radical scavenging assays (DPPH•, ABTS^+_, O2^-) were used along with CUPRAC and lipid peroxidation inhibitory assays, as well as anticholinesterase activity by Ellman method. Results: The best results were obtained for 4'-N,N-dimethyl flavonol (1) in both antioxidant and anticholinesterase activity tests, possibly due to its least steric hinderance effect. It exhibited remarkable DPPH free radical scavenging activity (2.43±0,09 μ ;g/mL) competing with a standard compound quercetin (2.10±0,10 μ ;g/mL). Moreover, the other tested flavonols also showed high antioxidant activities. Compounds 5 and 6 exhibited close IC50 values to those of compound 1. Conclusion: Antioxidant activity test results were found to be well correlated with anticholinesterase activity test results indicating possible role of antioxidant compounds in the treatment of Alzheimer’s disease.

Background: Gout is the most common inflammatory arthritis, which, if left untreated or inadequately treated, will lead to joint destruction, bone erosion and disability due to the crystal deposition. Uric acid transporter 1 (URAT1) was the promising therapeutic target for urate-lowering therapy. Objective: The goal of this work is to understand the structure-activity relationship (SAR) of a potent lesinurad-based hit, sodium 2-((5-bromo-4-((4-cyclopropyl-naphth-1-yl)methyl)-4H-1,2,4-triazol-3- yl)thio)acetate (1c), and based on that discover a more potent URAT1 inhibitor. Methods: The SAR of 1c was systematically explored and the in vitro URAT1 inhibitory activity of synthesized compounds 1a-1t was determined by the inhibition of URAT1-mediated [8-14C]uric acid uptake by human embryonic kidney 293 (HEK293) cells stably expressing human URAT1. Results: Twenty compounds 1a-1t were synthesized. SAR analysis was performed. Two highly active URAT1 inhibitors, sodium 2-((5-bromo-4-((4-n-propylnaphth-1-yl)methyl)-4H-1,2,4-triazol-3- yl)thio)acetate (1j) and sodium 2-((5-bromo-4-((4-bromonaphth-1-yl)methyl)-4H-1,2,4-triazol-3- yl)thio)acetate (1m), were identified, which were 78- and 76-fold more active than parent lesinurad in in vitro URAT1 inhibitory assay, respectively (IC50 values for 1j and 1m were 0.092 μM and 0.094 μM, respectively, against human URAT1 vs 7.18 μM for lesinurad). Conclusion: Two highly active URAT1 inhibitors were discovered. The SAR exploration also identified more flexible naphthyltriazolylmethane as a novel molecular skeleton that will be valuable for the design of URAT1 inhibitors, as indicated by the observation that many of the synthesized naphthyltriazolylmethane- bearing derivatives (1b-1d, 1g, 1j and 1m) showed significantly improved UART1 inhibitory activity (sub-micromolar IC50 values) as compared with lesinurad which has the rigid naphthyltriazole skeleton.

Background: Angiogenesis involves the process of sprouting of microvessels from preexisting microvasculature and is held responsible for the growth, malignancy and metastasis of cancer. Heat shock protein Hsp90 has been proven responsible for indirectly inducing multiple pathways leading to angiogenesis and metastasis in cancer. Recent researches shift towards proposing novel phytochemicals as possible antiangiogenic agents. Objective: The study aims towards Virtual screening of compounds from Cucurbitaceae family and their Druglikeliness and PreADMET filtering in search of potent lead as Vitexin, targeting Hsp90 and hence restraining angiogenesis. Materials and Methods: Structures of phytochemicals from Cucurbitaceae family were retrieved from PubChem database and were converted into suitable 3-D structures. The target protein, Hsp90 was retrieved from RCSB Protein Data Bank. Phytochemicals of Cucurbitaceae family were filtered through enumerated Lipinski’s rule of five and ADMET toxicity profiling and the filtered compounds were further taken forward for molecular docking analysis and interaction studies using AutoDock Tools 4.0. Results: The docking results revealed Vitexin, a prominent glycosylated natural flavonoid, showing promising inhibitory potential against Hsp90 with binding energy of -8.80 kcal/mole and Ki 353.24 nM as compared to its known inhibitor Ganetespib having binding energy of -7.33 kcal/mole and Ki 4260 nM. Vitexin also exhibits better drug having properties with satisfactory ADMET profiling in relation to Ganetespib. Conclusion: The result proposes Vitexin to hold prominent antiangiogenic potential surpassing different in silico parameters and thus expected to be a multi-targeted novel antiangiogenic lead.

Background: Pistacia integerrima has many medicinal uses in therapeutic as well as folk medicine. P. integerrima has been used for the treatment of different ailments such as blood purifier, anti-inflammatory, and as remedy for gastrointestinal disorders such as vomiting and diarrhea, expectorant, cough, asthma and fever. Objective: The main objective of this research work was to evaluate the effect of pistagremic acid (PA) isolated from the galls of Pistacia integerima in acute toxicity and gastrointestinal (GIT) motility tests. Methods: Compound 1 namely pistagremic acid (PA) (at 10, 50, 100 mg/kg i.p) were assessed for their in-vivo gastrointestinal motility test using charcoal screening model. Results: Results revealed that pretreatment of PA exhibited substantial safety in acute toxicity test up to the dose of 500 mg/kg p.o. However, when studied in charcoal meal GI transit test, PA caused significant (p<0.05) attenuation of GIT motility and an increase in intestinal transit time, comparable to atropine (a muscarinic receptor blocking agent). Conclusion: In conclusion, PA displayed a strong dose-dependent reduction in GIT motility with considerable safety.

Background: A growing evidence indicates that marine sponge Phyllospongia sp. is one of rich sources of 20, 24-bishomoscalarane sesterterpenes with potent biological activities. In order to search more bioactive 20, 24-bishomoscalarane sesterterpenes for new drug discovery, chemical investigation was carried out on an Indonesian marine sponge P. papyrecea. Methods: Bioassay-guided fractionation was carried out on its dichloromethane extract. And nine compounds were purified and isolated using HPLC. Their chemical structures were determined by a combination of spectroscopic and spectrometric data, including 1D-, 2D-NMR and HRESI-MS. Their cytotoxic activities were performed on three human tumor cell lines A549, MCF-7 and HeLa using the CCK-8 method. Results: One new 20, 24-bishomoscalarane sesterterpene, phyllactone H (9), was isolated and elucidated together with phyllactones A-B (1-2) and D-G (3-6), 12 α, 24-dihydroxy-20, 24-dimethyl-15, 17- scalaradien-25, 24-olides (7-8). Compounds 1 and 2, 3 and 4, 5 and 6, 7 and 8 were C-24 anomers and inseparable mixtures, respectively. The 1H and 13C-NMR data for 7/8 were firstly reported in this paper. Conclusion: Compounds 1-9 possessed in vitro moderate cytotoxicities against A549, MCF-7 and HeLa cells with IC50 values of less than 25 μM.

Background: Biaryl seven-membered lactones (BSLs), the target compounds are a class of bioactive compounds with anti-arrhythmic activity, which also serve as a starting material or structural units for chemical synthesis. Objective: To report a simple and efficient procedure for the synthesis of biaryl seven-membered lactones. Method: Under microwave, the umpolung reaction was promoted by N-heterocyclic carbenes under oxygen, with anhydrous potassium carbonate as base and with 1,4,7,10,13,16-Hexanoxacyclooctadecane (18-crown-6) as a phase-transfer catalyst. Results: The practical protocol was found to be compatible with different structurally diverse substrates and with moderate to excellent yields. Conclusion: This synthesis method has the advantage of high efficacy and novelty, short reaction time, operation simplicity, mild condition and high yields, providing a useful and atom-economic approach to the synthesis of BSLs.