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In this study, a series of coumarin–indole hybrids have been synthesized and evaluated for their lipid lowering activity. Preliminary biological screening of the synthesized compounds was undertaken in an in vitro model of the HMG-CoA reductase enzyme, and the activity was confirmed in Triton WR-1339 induced hyperlipidemic rats. Among the hybrids, compound 26 was found to be the best as it significantly reduced the serum and hepatic lipid profiles in an HFD-fed hyperlipidemic rat model. The mechanism of action seems to be associated with the regulation of HMG-CoA reductase activity in the liver, which is in good agreement with binding mode studies. Compound 26 exhibited favorable pharmacokinetic behavior for its oral administration, which underscores the potential of this template as a new class of hypolipidemic agents.

In the quest for novel scaffolds for the management of androgen sensitive prostatic disorders like prostate cancer and benign prostatic hyperplasia, a series of twenty-six aryl/heteroaryl piperazine derivatives have been described. Three compounds, 8a, 8c and 9a, exhibited good activity profiles against an androgen sensitive prostate cancer cell line (LNCaP) with EC50 values of 9.8, 7.6 and 11.2 μM, respectively. These compounds caused a decrease in luciferase activity and a decline in PSA and Ca2+ levels, which are indicative of their anti-androgenic and α1A-adrenergic receptor blocking activities, respectively. Compound 9a reduced the prostate weight of rats (47%) and in pharmacokinetic analysis at 10 mg kg−1 it demonstrated an MRT of ∼14 h post dose, exhibiting high levels in prostate. Compound 9a docked in a similar orientation to hydroxyflutamide on an androgen receptor and showed strong π–π interactions. These findings reveal that compound 9a is a promising candidate for management of prostatic disorders with anti-androgenic and α1A-blocking activities.

A series of new dihydropyrimidinone–semicarbazone hybrids were successfully synthesised by integrating regioselective multicomponent reaction with the pharmacophore hybridization approach. All the synthesised compounds were evaluated for their hLig1 inhibition potency and most of them were found to be good to moderately active. Out of the tested derivatives, compound 6f showed selective anti-proliferative activity against HepG2 cells in a dose-dependent manner with an IC50 value of 10.07 ± 1.2. It also reduced cell survival at ≤20 μM concentration. Further, analysis of treated HepG2 cell lysates by western blot assay showed increased γ-H2AX levels and upregulation of p53, leading to apoptosis. In silico docking results explain the binding modes of compound 6f to the DNA-binding domain of hLig1 enzyme thereby preventing its nick sealing activity. In addition, the favourable pharmacokinetic properties suggest that this new class of hLig1 inhibitors could be promising leads for further drug development.

The processes of DNA replication and repair are accomplished by the concerted action of several proteins. Among them human DNA ligases play an important role during the last step of almost all DNA replication and repair processes, where they seal the nicks between DNA strands. In humans, three kinds of DNA ligases (human DNA ligase I, III, IV) are found. DNA ligase I (hLigI) is involved in both DNA replication as well as in DNA repair pathways and is reported to be over-expressed in rapidly dividing cells, including cancer cells. For this reason, in this study we have targeted hLigI for studying its response as a novel anticancer target. We have screened for ligase I inhibitors from our in-house small molecule library by a previously validated pharmacophore based virtual screening method and found a novel hLigI inhibitor. This compound (S-097/98) demonstrated antiproliferative activities specifically in DLD-1 (colon), MDA-MB-231 (triple negative breast) and HepG2 (liver) cancer cell lines at low micromolar concentrations of 6–7 μM. Mechanistic studies show that the compound can directly interacts with the hLigI protein and inhibits ligation of both the purified protein in vitro, as well as in cell lysate of DLD-1 cells treated with the inhibitor. The compound also arrests cell cycle progression at the G2/M phase and increases the nuclear size of DLD-1 cancer cells, thereby demonstrating its antiproliferative activity. Finally, the compound promotes cellular apoptosis in DLD-1 cells.

We have designed new potent inhibitors of thymidine monophosphate kinase of Mycobacterium tuberculosis (TMPKmt) using structure-based molecular design. Three-dimensional (3D) models of TMPKmt–inhibitor complexes were prepared by in situ modification of the crystal structure of TMPKmt co-crystallized with the natural substrate deoxythymidine monophosphate (dTMP) (PDB entry code: 1G3U) and a training set of 20 thymine derivatives bearing an aliphatic or aromatic group attached through a spacer (THMDs) with known inhibitory potencies. A QSAR model was elaborated for the training set THMDs and a linear correlation was established between the computed free energies of THMD binding and observed enzyme inhibition constants (Kexpi). Validation of this QSAR model was performed with 3D-QSAR pharmacophore generation (PH4). Structural information derived from the 3D model and breakdown of computed TMPKmt–THMDs interaction energies up to individual active site residue contributions helped us to design new more potent TMPKmt inhibitors. We obtained a reasonable agreement between the free energies of TMPKmt–THMDs complexation (ΔΔGcom) and Kexpi values, which explained approximately 93% of the TMPKmt inhibition data (pKi = −0.1422 ΔΔGcom + 4.9199, R2 = 0.93). Similar agreement was established for the PH4 pharmacophore model (pKexpi = 1.0016 × pKprei + 0.0077, R2 = 0.95). Comparative analysis of the active site residue contributions directed substitutions to various positions of the naphtholactam or naphthosultam moeties and suggested their replacement with phthalimido or isoindolinone or indanone rings, which led to a predicted increase of the inhibitory potency. The predicted Kprei for the best inhibitor candidate reached the picomolar range for aliphatic acyclic nucleoside analogs and for benzyl pyrimidine-like analogs. This computational approach, which combines molecular modelling, pharmacophore generation and analysis of TMPKmt–THMDs interaction energies resulted in a set of proposed TMPKmt inhibitors. It can thus direct medicinal chemists in their search for new antituberculotic agents.

Fluconazole based novel mimics containing 1,5-disubstituted 1,2,3-triazoles were synthesized by using Ru catalysed 1,3 dipolar cycloaddition. All the newly synthesized compounds and pure enantiomers were more potent than fluconazole against Candida albicans. Docking of 9A and 9B showed different conformation in the active site of Cyp51 of Candida albicans. The more active compounds 2 and 2A did not exhibit any toxicity up to 3.12 μg mL−1 against mammalian cell line L929.

Drug resistance to established antifungals such as azole derivatives (fluconazole and ketoconazole) is driving the rise in global mortality due to fungal infection. Identification of new molecular entities structurally unrelated to these may represent a valid strategy to overcome resistance to currently available drugs. In an effort to develop highly potent antifungal agents, we report herein a series of 27 compounds of dithiocarbamate and the rhodanine molecules containing pyridine moiety and their antifungal activity. Among the synthesized compounds, several analogues have shown potent antifungal activity. The potent compounds against Candida albicans strain were further tested for in vitro anticandidal activity and amphotericin B-resistant strain of Candida albicans. Several derivatives 4a–f, 6, and 7k–n were found to be more effective (MIC = 0.39 – 3.12 μg mL−1) against Candida albicans MTCC183 and further these compounds, except 4e, 4f, and 7m, showed significant activity against amphotericin B-resistant strain of Candida albicans than that of fluconazole. Moreover, these analogues did not exhibit any toxicity up to MIC 3.12 μg mL−1 against mammalian cell line L929. A molecular docking study was undertaken to understand the mode of action of the active compounds towards prospective target lanosterol 14α-demethylase (CYP-51).