Current Topics in Medicinal Chemistry - Volume 15, Issue 11, 2015

The 9-(bromoalkyl)-1,4-dimethyl-9H-carbazole (2a-d) derivatives, characterized by the presence of five or seven methylenic spacer groups bonded to the carbazole nitrogen, have been synthesized from the corresponding 1,4- dimethyl-9H-carbazole and appropriate dibromoalkane following a general synthetic method. All the prepared species have been fully characterized by means of IR, and 1H and 13C NMR spectroscopy, GC-MS and Elemental analysis. Good crystals of the 2c have been obtained and the crystal structure has been solved by means of X-ray diffractometry. In order to study the cytotoxic effect of 2a, 2b, 2c, 2d carbazole derivatives on A2780 ovarian cancer cells, we performed MTT assay after exposure of this cell population to those compounds in a concentration range from 1 to 10μM. Finally, we want to verify whether the cytotoxic effect of the 2c carbazole is mediated by apoptotic mechanisms, by performing chromatin condensation assay on the A2780 cell cultures upon the carbazole treatment at concentration of 10 μM for 72h. All together our data demonstrate that carbazole derivatives exert inhibitory effects on ovarian cancer cell growth, highlighting a stronger and a dose-dependent anti proliferative activity displayed by 2c carbazole, designating this compound, as a better candidate in the treatment of human ovarian cancer.

To investigate the theoretical model of the three-dimensional structure of multidrug resistance protein 1(P-glycoprotein, expressed by MDR1 gene of E. histolytica) and its molecular docking with anti-amoebic agents. The theoretical model of multidrug resistance protein 1(P-glyoprotein, expressed by MDR1 gene of E. histolytica) was predicted by homology modeling on the structure of the 3G61. Docking studies were performed to investigate the interaction of p-glycoprotein with antiamoebic gents. MRPEH1F is significant model for p-glycoprotein and have total of 114 amino acid residues. The model is well supported by cross validation data generated after analyzing criss-cross residues, local geometry check as well as ramachandran plot. Molecular docking of MRPEH1F revealed that all the test molecules have strong binding affinity along with significant interactions. Henceforth, none of the molecules will probably be effective for the multidrug resistant strains of E. histolytica.

A new class of 4-thiazolidinones clubbed with quinozolinone nucleus has been synthesized. The title compounds were screened for their in vitro antimicrobial and anticancer potentials. Results of antimicrobial and anticancer study revealed that compounds 7 (pMICam = 1.69 μM/ml) and 2 (IC50 = 12.83 μM) were found to be the most potent antimicrobial and anticancer agents respectively. QSAR studies indicated that antimicrobial activity of synthesized 4-thiazolidinone derivatives was governed by the electronic parameters, dipole moment (μ), energy of highest occupied molecular orbital (HOMO), lipophilic parameter, log P and topological parameter, valence third order molecular connectivity index (3χv).

A series of twenty one chalcone derivatives having indole moiety were synthesized and were evaluated against four human cancer cell lines. Indolyl chalcones 1a, 1b, 1d, 1f-1j, 2c, 2e, 2i showed good anticancer activity. Chalcones 1b and 1d were the most active and selective anticancer agents with IC50 values <1μg/ml and 1.51μg/ml, against WRL-68 cell line, respectively. Molecular mechanism was explored through in silico docking & ADMET studies.

Isolation of andrographolide from Andrographis paniculata, preparation of a library of derivatives via 1,3-dipolar cycloaddition of andrographolide with azomethine ylides generated from isatin derivatives or acenaphthoquinone and seconday α-amino acids, evaluation of the anticancer potential of the products, quantitative structure activity relationship studies and pharmacokinetic parameter determination have been described. 2D QSAR studies revaled that steric effects and van der Waals interactions play major roles in the determination of antiproliferative activity of these derivatives. 3D QSAR study predicted that the benzyl substitution at N20 position may be important for higher steric interaction. Pharmacokinetic studies with two most potent analogues revealed moderate chemical stability but poor aqueous solubility, metabolic stability and permeability with significant CYP3A4 inhibition.

Bioactivity guided separation of combined n-hexane and chloroform extracts of Oplismenus burmannii resulted in the isolation and characterization of five new glycoglycerolipids, (2S)-1,2,6’-tri- O-hexadecanoyl-3-O-β-D-galactopyranosyl glycerol (1a), (2S)-1,2,6’-tri-O-[(9Z,12Z)-octadeca-9,12- dienoyl]-3-O-β-D-galactopyranosyl glycerol (1b), (2S)-1,6’-di-O-[(9Z,12Z)-octadeca-9,12-dienoyl]-3- O-β-D-galactopyranosyl glycerol (2b), (2S)-1,6’-di-O-[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-O-β-D-galactopyranosyl glycerol (2c), and (2S)-1,2-di-O-[(9Z,12Z)-octadeca-9,12-dienoyl]-3-O-(6- sulpho-α-D)-quinovopyranosyl glycerol (3b) along with five known glycoglycerolipids (1c, 2a, 3a, 3c and 4), a cerebroside (5), three monoacylglycerols (6a-c) and α-linoleic acid (7). The isolated compounds, 1-5 were in-vitro tested for their antihyperglycemic potential in terms of increase in 2-deoxyglucose uptake in L6-GLUT4myc myotube cells. The results showed that compounds, 1-5 were showing 1.52 (P<0.05), 1.50 (P<0.05), 1.28, 1.49 (P<0.05) and 1.50 (P<0.05) fold increase in the glucose uptake at concentration of 10 μg/mL and 1.71 (P<0.001), 1.74 (P<0.001), 1.50 (P<0.05), 1.76 (P<0.001) and 1.74 (P<0.001) fold increase in the glucose uptake at concentration of 25 μg/mL respectively. However, standard drug Rosiglitazone increases the glucose uptake by 1.59 fold at the concentration of 10μM. Further work on optimization of the anti-diabetic lead is under progress.

Estrogens control a wide number of aspects of human physiology and play a key role in multiple diseases, including cancer. Estrogens act by binding to and activating the cognate receptor (ER), however numerous studies have revealed that the G protein-coupled receptor named GPR30/GPER mediates also estrogen signals. As ER and GPER share the ability to bind to same compounds, the use of GPER-selective ligands has allowed a better understanding of the biological responses mediated by GPER. In the present study, we designed and synthesized two novel carbazole derivatives and then investigated their ability to interact with and activate the GPER-mediated transduction pathway in breast cancer cells. Both compounds did not activate the classical ER in MCF7 cells, whereas one of the two compounds synthesized triggered through GPER the rapid ERK activation in ER-negative SkBr3 cells, demonstrating a good affinity for GPER in docking studies. The characterization of this novel selective GPER agonist could represent a potential useful tool to provide further insights into the physiopathological role exerted by GPER.

Bioactivity guided isolation of Glycyrrhiza glabra (Leguminosae / Fabaceae) roots resulted in the characterization of 18β-glycyrrhetinic acid as a major anti-tubercular agent. Further, GA-1 was semi-synthetically converted into its nine derivatives, which were in-vitro evaluated for their antitubercular potential against Mycobacterium tuberculosis H37Rv using BACTEC-460 radiometric susceptibility assay. All the derivatives were active, but the benzylamide (GA-8, MIC 12.5μg/ml) and ethyl oxylate (GA-3, MIC 25.0 μg/ml) derivatives were significantly active against the pathogen. This was further supported by the molecular docking studies, which showed adequate docking (LibDock) scores for GA-3 (120.3) and GA-8 (112.6) with respect to the standard anti-tubercular drug, rifampicin (92.94) on the DNA-directed RNA polymerase subunit beta (rpoB) target site. Finally, the in silico pharmacokinetic and drug-likeness studies showed that GA-3 and GA- 8 possesses drug-like properties. This is the first ever report on the anti-tubercular potential of GA and its derivatives. These results may be of great help in anti-tubercular drug development from a very common, inexpensive, and non toxic natural product.

A series 3/4-bromo-N&apos-(substituted benzylidene/furan-2-ylmethylene/5-oxopentylidene/3- phenylallylidene)benzohydrazides (1-23) was synthesized and characterized by physicochemical and spectral means. The synthesized compounds were screened for their antimicrobial and anticancer potentials. Antimicrobial activity results indicated that compound 12 (pMICam = 1.67 μM/ml) was the most potent antimicrobial agent. The synthesized benzohydrazides were also having good anticancer potential and compound 22 (IC50 = 1.20 μM μM) was found to be the most potent anticancer agent which was more potent than standard drugs, tetrandrine (IC50 = 1.53) and 5- fluorouracil (IC50 = 4.6 μM). QSAR studies indicated that antimicrobial activity of synthesized compounds was best described by electronic parameter, total energy (Te) and topological parameters, valance zero order molecular connectivity index (0χv) and Wiener index (W).