nan Shamsuzzaman

Bioactive Benzofuran derivatives: A review.

In natures collection of biologically active heterocycles, benzofuran derivatives constitute a major group. The broad spectrum of pharmacological activity in individual benzofurans indicates that this series of compounds is of an undoubted interest. Benzofuran and its derivatives have attracted medicinal chemists and pharmacologists due to their pronounced biological activities and their potential applications as pharmacological agents. Due to the wide range of biological activities of benzofurans, their structure activity relationships have generated interest among medicinal chemists, and this has culminated in the discovery of several lead molecules in numerous disease conditions. The outstanding development of benzofuran derivatives in diverse diseases in very short span of time proves its magnitude for medicinal chemistry research. The present review is endeavour to highlight the progress in the various pharmacological activities of benzofuran derivatives in the current literature with an update of recent research findings on this nucleus.

Review: biologically active pyrazole derivatives

Nitrogen-containing heterocyclic compounds and their derivatives have historically been invaluable as a source of therapeutic agents. Pyrazole, which has two nitrogen atoms and aromatic character, provides diverse functionality and stereochemical complexity in a five-membered ring structure. In the past decade, studies have reported a growing body of data on different pyrazole derivatives and their innumerable physiological and pharmacological activities. In part, such studies attempted to reveal the wide range of drug-like properties of pyrazole derivatives along with their structure–activity relationships in order to create opportunities to harness the full potentials of these compounds. Here, we summarize strategies to synthesize pyrazole derivatives and demonstrate that this class of compounds can be targeted for the discovery of new drugs and can be readily prepared owing to recent advances in synthetic medicinal chemistry.

Synthesis and anti-tumor evaluation of B-ring substituted steroidal pyrazoline derivatives

The synthesis and anti-tumor activity screening of new steroidal derivatives (4-18) containing pharmacologically attractive pyrazoline moieties are performed. During in vitro anticancer evaluation, the newly synthesized compounds displayed moderate to good cytotoxicity on cervical and leukemia cancer cell lines. In addition these compounds were found to be nontoxic to normal cell (PBMCs) (IC50>50 μM). The structure-activity relationship is also discussed. The most effective anticancer compound 9 was found to be active with IC50 value of 10.6 μM. It demonstrated significant antiproliferative influence on Jurkat cell lines. The morphological changes and growth characteristics of HeLa cells treated with compound 4 were analyzed by means of SEM.

Neurodegenerative diseases linked to misfolded proteins and their therapeutic approaches: A review.

Neurodegenerative diseases, such as Alzheimers, Parkinsons, Creutzfeldt-Jacob, Huntingtons diseases and amyotrophic lateral sclerosis, are mainly characterized by the massive deposition of misfolded protein aggregates consequent to aberrant production or overexpression of specific proteins. The development of new therapeutics for the treatment of neurodegenerative pathophysiologies currently stands at a crossroads. This presents an opportunity to transition future drug discovery efforts to target disease modification, an area in which much still remains unknown. In this review we examine recent progress in the area of neurodegenerative drug discovery, focusing on some of the most common targets.

Synthesis of Steroidal Spiro-1′,2′,4′-triazolidine-3′-thiones

Abstract Steroidal ketone thiosemicarbazones (4–6), obtained from the corresponding ketones(1–3), on oxidative cyclization with H2O2 at 0°C provide title compounds (7–9), respectively. The structures of these compounds have been established on the basis of their elemental analytical and spectral data.

Synthesis and characterization of steroidal heterocyclic compounds, DNA condensation and molecular docking studies and their in vitro anticancer and acetylcholinesterase inhibition activities

A facile, convenient and efficient approach for the synthesis of a new series of steroidal heterocyclic compounds (4–12) by reacting a mixture of compounds (1e–3e) with o-aminothiophenol/o-aminophenol/o-phenylenediamine is reported. The structural assignment of products is confirmed on the basis of IR, 1H NMR, 13C NMR, MS and analytical data. The compounds obey the Lipinskis ‘Rule of Five’ analysis based on computational prediction and pharmacokinetic properties. The anticancer activity has been tested in vitro against three cancer cell lines Hep3B (human hepatocellular carcinoma), MCF7 (human breast adenocarcinoma), HeLa (human cervical carcinoma) and one non-cancer normal cell i.e. PBMCs (peripheral blood mononuclear cell) by MTT assay. In addition, the synthesized compounds are also tested for their in vitro antioxidant activity by various reported methods in which compounds 10–12 exhibited good antioxidant activity. Nonenzymatic degradation of DNA has been investigated. The acetylcholinesterase (AChE) inhibitor activities of the steroidal derivatives are also evaluated using Ellmans method. Moreover, the application of compound 6 as a DNA gene transporter is evaluated by DNA condensation and ascertained by employing TEM and AFM, which illustrate that the compound 6 induces the condensation of CT-DNA. Molecular docking studies further characterize the interaction of the synthesized compounds with DNA.

Molecular spectroscopic and thermodynamic studies on the interaction of anti-platelet drug ticlopidine with calf thymus DNA

Ticlopidine is an anti-platelet drug which belongs to the thienopyridine structural family and exerts its effect by functioning as an ADP receptor inhibitor. Ticlopidine inhibits the expression of TarO gene in S. aureus and may provide protection against MRSA. Groove binding agents are known to disrupt the transcription factor DNA complex and consequently inhibit gene expression. Understanding the mechanism of interaction of ticlopidine with DNA can prove useful in the development of a rational drug designing system. At present, there is no such study on the interaction of anti-platelet drugs with nucleic acids. A series of biophysical experiments were performed to ascertain the binding mode between ticlopidine and calf thymus DNA. UV-visible and fluorescence spectroscopic experiments confirmed the formation of a complex between ticlopidine and calf thymus DNA. Moreover, the values of binding constant were found to be in the range of 103M-1, which is indicative of groove binding between ticlopidine and calf thymus DNA. These results were further confirmed by studying the effect of denaturation on double stranded DNA, iodide quenching, viscometric studies, thermal melting profile as well as CD spectral analysis. The thermodynamic profile of the interaction was also determined using isothermal titration calorimetric studies. The reaction was found to be endothermic and the parameters obtained were found to be consistent with those of known groove binders. In silico molecular docking studies further corroborated well with the experimental results.

Microwave-assisted one pot synthesis, characterization, biological evaluation and molecular docking studies of steroidal thiazoles

In the present manuscript, a series of steroidal thiazole derivatives (4-6, 8) have been synthesized in efficient manner by one step reaction methodology employing microwave irradiation. The synthesis involves the reaction of steroidal ketones (1-3, 7) with thiosemicarbazide and phenacyl bromide. Structural assignment of the products was confirmed on the basis of IR, 1H NMR, 13C NMR, MS and analytical data. The synthesized compounds were screened for in vitro antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. In addition, the products 4-6, 8 were also tested for pBR322 DNA cleavage activity, genotoxicity, reactive oxygen species (ROS) production and RBC hemolysis. Molecular docking analysis was carried out to validate the specific binding mode of the newly synthesized compounds into the active site of DNA. Docking showed formation of more stable complexes of compounds 4 and 8 with the free binding energies -8.1 and -8kcal/mol, respectively. Hence, it could be suggested that the steroidal compounds bearing a core thiazole scaffold would be a potent biological agent.

In vitro cytotoxcity and interaction of new steroidal oxadiazinanones with calf thymus DNA using molecular docking, gel electrophoresis and spectroscopic techniques

Herein we report synthesis of new steroidal oxadiazinanones from steroidal ketones. After characterization by spectral and analytical data, the interaction studies of compounds (4-6) with DNA were carried out by UV-vis, fluorescence spectroscopy and gel electrophoresis. The compounds bind to DNA preferentially through electrostatic and hydrophobic interactions with Kb; 1.8×10(4) M(-1), 2.2×10(4) M(-1) and 2.6×10(4) M(-1), respectively, indicating the higher binding affinity of compound 6 towards DNA. Gel electrophoresis showed the concentration dependent cleavage activity of compound 6 alone or in presence of Cu (II) causes the nicking of supercoiled pBR322 and it seems to follow the mechanistic pathway involving generation of hydroxyl radicals that are responsible for initiating DNA strand scission. Molecular simulations suggest that compounds binds through minor groove of DNA. MTT assay depicted promising anticancer activity of compound 5 and 6 particularly against HL-60 and MCF-7. The apoptotic degradation of DNA was analyzed by agarose gel electrophoresis and visualized by ethidium bromide staining (comet assay). The results revealed that compound 6 has better prospectus to act as cancer chemotherapeutic candidate which warrants further in vivo anticancer investigations.

SYNTHESIS OF 1',3'-DIOXOLAN-2'-ONE BY THE REACTION OF STEROIDAL OXIRANES WITH CARBON DIOXIDE: SYNTHESIS OF FIVE-MEMBERED CIS CYCLIC CARBONATES

The reaction of 3β-acetoxy-5,6α-epoxy-5α-cholestane 1, its 3β-chloro analogue 2, and 5,6α-epoxy-5α-cholestane 3 with carbon dioxide gas in the presence of sodium bromide as catalyst with continuous stirring at 100 °C for 30 min affords selectively the corresponding 1′,3′,-dioxolan-2′-ones (steroidal cyclic cis-carbonates) 4–6 in excellent yields. The structures of these products have been established on the basis of their elemental analysis and spectral data (infrared, 1H NMR, and mass).