Browsing by Author "Kumar B."

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    Evaluation of heavy metals toxicity in the groundwater of some villages of Sirsa district of Haryana, India
    (Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma, 2019) Kumar P.; Jain S.; Kumar B.
    An attempt was made to assess the groundwater quality in some rural parts of Sirsa district of Haryana, India with respect to heavy metals contamination. For this purpose, 23 groundwater samples were collected from the bore wells during pre-monsoon in 2017 from some selected locations in the study area where the groundwater is used for drinking and agricultural activities. The samples have been analyzed for seven heavy metals viz. Mn, As, Zn, Cd, Pb, Cu and Cr using ICP-MS. The results were compared with the BIS standards to assess the suitability of groundwater for drinking. To assess the heavy metal contamination, the heavy metal pollution index (HPI), metal index (MI) and hazard index (HI) was calculated. The groundwater with HI > 1 falls in the high pollution category. In our study, 10 out of 23 samples were not fit to consume by the infants and all the 23 samples were found to be unfit for both the children and the adults. The correlation matrix showed a good correlation of HPI with Mn (r = 0.998), As (r = 0.993), Cu (r = 0.998), Cr (r = 0.998) and with Pb (r = 0.998) whereas the correlation of MI with Mn (r = 0.998), As (r = 0.994), Cu (r = 0.998), Cr (r = 0.999) and with Pb (r = 0.998).
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    Metal- And Solvent-Free Multicomponent Decarboxylative A3-Coupling for the Synthesis of Propargylamines: Experimental, Computational, and Biological Investigations
    (American Chemical Society, 2020) Kaur P.; Kumar B.; Gurjar K.K.; Kumar R.; Kumar V.; Kumar R.
    Decarboxylative A3-coupling of ortho-hydroxybenzaldehydes, secondary amines, and alkynoic acids is performed under catalyst and solvent-free conditions. The developed methodology provided a waste-free method for the synthesis of hydroxylated propargylamines which are versatile precursors for various bioactive heterocyclic scaffolds. The experimental and density functional theory studies revealed that the in situ-formed ortho-quinonoid intermediate (formed from ortho-hydroxybenzaldehyde and amine) undergoes a concerted Eschweiler-Clarke type decarboxylation with alkynoic acids. The synthesized compounds were evaluated for MAO-A, MAO-B, and AChE inhibitory activities as potential drug candidates for the treatment of various neurological disorders. Compound 4f was found to be the most potent and selective MAO-B (high selectivity over MAO-A) and AChE inhibitor in the series with IC50 values of 4.27 ± 0.07 and 0.79 ± 0.03 ?M, respectively.
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    Synthesis, Biological Evaluation and Molecular Modeling Studies of Propargyl-Containing 2,4,6-Trisubstituted Pyrimidine Derivatives as Potential Anti-Parkinson Agents
    (John Wiley and Sons Ltd, 2018) Kumar B.; Kumar M.; Dwivedi A.R.; Kumar V.
    Monoamine oxidase B (MAO‐B) inhibitors are potential drug candidates for the treatment of various neurological disorders including Parkinson's disease. A total of 20 new propargyl‐containing 2,4,6‐trisubstituted pyrimidine derivatives were synthesized and screened for MAO inhibition using Amplex Red assays. All the synthesized compounds were found to be reversible and selective inhibitors of the MAO‐B isoform at sub‐micromolar concentrations. MVB3 was the most potent MAO‐B inhibitor with an IC50 value of 0.38±0.02 μμ , whereas MVB6 (IC50=0.51±0.04 μμ ) and MVB16 (IC50=0.48±0.06 μμ ) were the most selective for MAO‐B with a selectivity index of more than 100‐fold. In cytotoxic studies, these compounds were found to be nontoxic to human neuroblastoma SH‐SY5Y cells at concentrations of 25 μm . MVB6 was found to decrease the intracellular level of reactive oxygen species to 68 % at 10 μm concentration, whereas other compounds did not produce significant changes in reactive oxygen species levels. In molecular modeling studies, MVB3 displayed strong binding affinity for the MAO‐B isoform with a dock score of −10.45, in agreement with the observed activity. All the compounds fitted well in the hydrophobic cavity of MAO‐B. Thus, propargyl‐substituted pyrimidine derivatives can be promising leads in the development of potent, selective and reversible MAO‐B inhibitors for the treatment of Parkinson's disease.