Browsing by Author "Kalra S."

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    E-pharmacophore guided discovery of pyrazolo[1,5-c]quinazolines as dual inhibitors of topoisomerase-I and histone deacetylase
    (Academic Press Inc., 2020) Joshi G.; Kalra S.; Yadav U.P.; Sharma P.; Singh P.K.; Amrutkar S.; Ansari A.J.; Kumar S.; Sharon A.; Sharma S.; Sawant D.M.; Banerjee U.C.; Singh S.; Kumar R.
    In the quest to ameliorate the camptothecin (CPT) downsides, we expedite to search for stable non-CPT analogues among 11 motifs of pyrazoloquinazolines reported. E-pharmacophore drug design approach helped filtering out pyrazolo[1,5-c]quinazolines as Topoisomerase I (TopoI) 'interfacial' inhibitors. Three compounds, 3c, 3e, and 3l were shown to be potent non-intercalating inhibitors of TopoI specifically and showed cancer cell-specific cytotoxicity in lung, breast and colon cancer cell lines. The compounds induced cell cycle arrest at S-phase, mitochondrial cell death pathway and modulated oxidative stress in cancer cells. Furthermore, a preliminary study was conducted to explore the feasibility of these compounds to be developed as dual TopoI-HDAC1 (histone deacetylase 1) inhibitors (4a) to combat resistance. Compound 4a was found to possess dual inhibitory capabilities in-vitro. Cytotoxic potential of 4a was found to be significantly higher than parent compound in 2D as well as 3D cancer cell models. Probable binding modes of 4a with TopoI and HDAC1 active sites were examined by molecular modelling.
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    Novel 2-(substituted phenyl Imino)-5-benzylidene-4-thiazolidinones as possible non-ulcerogenic tri-action drug candidates: synthesis, characterization, biological evaluation And docking studies
    (Birkhauser Boston, 2019) Chawla P.; Kalra S.; Kumar R.; Singh R.; Saraf S.K.
    The present research was aimed at the synthesis and screening of 35 novel 2-(substituted phenyl imino)-5-benzylidene-4-thiazolidinones having different substitutions at imino phenyl and arylidene groups. The title compounds were synthesized by Knoevenagel condensation at the 5th position of the 4-thiazolidinone ring, in the presence of sodium acetate. The structures were assigned on the basis of spectral data. The compounds were screened for in vivo anti-inflammatory, antinociceptive and in vitro free-radical scavenging activities. The compounds exhibited significant activities when compared with standard drugs. The distinctive property of the derivatives was that none of them had an acidic group, like conventional NSAIDs, but exhibited significant in vivo activity in acute inflammation models. Further, the active compounds of each series were docked against cyclooxygeanase (COX)-2 enzyme using Glide module of Maestro 11.1 program. It was evident from the docking results that 3-chlorophenylimino and 2-chloro moiety on 5-benzylidene nucleus of the 4-thiazolidinone derivative (30) could easily fit into the COX-2-binding pocket, considered as critical interaction for COX-2 inhibition. Interestingly, some of the compounds exhibited the potential of becoming dual action or even triple action drug candidates, which could target degenerative disorders associated with excessive free-radical generation.
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    Recent advancements in mechanistic studies and structure activity relationship of FoF1 ATP synthase inhibitor as antimicrobial agent
    (Elsevier Masson SAS, 2019) Narang R.; Kumar R.; Kalra S.; Nayak S.K.; Khatik G.L.; Kumar G.N.; Sudhakar K.; Singh S.K.
    The emergence of drug resistance in infectious microbial strains can be overcome by development of novel drug molecules against unexploited microbial target. The success of Bedaquiline in recent years, as FoF1 ATP synthase inhibitor against XDR and MDR mycobacterium strains, has resulted in further exploration to identify more potent and safe drug molecules against resistant strains. FoF1 ATP synthase is the main energy production enzyme in almost all eukaryotes and prokaryotes. Development of bacterial ATP synthase inhibitors is a safe approach, without causing harm to mammalian cells due to structural difference between bacterial and mammalian ATP synthase target sites. This review emphasizes on providing the structural insights for FoF1 ATP synthase of different prokaryotes and will help in the design of new potent antimicrobial agents with better efficacy. Further, applications of synthetic and natural active antimicrobial ATP synthase inhibitors, reported by different research groups are summarized. Their SAR and mode of actions are also analysed. � 2019 Elsevier Masson SAS
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    A review on quinoline derived scaffolds as anti-HIV agents
    (Bentham Science Publishers, 2019) Chokkar N.; Kalra S.; Chauhan M.; Kumar R.
    After restricting the proliferation of CD4+T cells, Human Immunodeficiency Virus (HIV), infection persists at a very fast rate causing Acquired Immunodeficiency Syndrome (AIDS). This demands the vigorous need of suitable anti-HIV agents, as existing medicines do not provide a complete cure and exhibit drawbacks like toxicities, drug resistance, side-effects, etc. Even the introduction of Highly Active Antiretroviral Therapy (HAART) failed to combat HIV/AIDS completely. The major breakthrough in anti-HIV discovery was marked with the discovery of raltegravir in 2007, the first integrase (IN) inhibitor. Thereafter, the discovery of elvitegravir, a quinolone derivative emerged as the potent HIV-IN inhibitor. Though many more classes of different drugs that act as anti-HIV have been identified, some of which are under clinical trials, but the recent serious focus is still laid on quinoline and its analogues. In this review, we have covered all the quinoline-based derivatives that inhibit various targets and are potential anti-HIV agents in various phases of the drug discovery.