Browsing by Author "Kumar, R"

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Cyclocondensation reactions of an electron deactivated 2-aminophenyl tethered imidazole with mono/1, 2-biselectrophiles: synthesis and DFT studies on the rationalisation of imidazo [1, 2-a] quinoxaline versus benzo [f] imidazo [1, 5-a][1, 3, 5] triazepine selectivity switches.
(Royal Society of Chemistry, 2018) Joshi, G.; Chauhan, M; Kumar, R; Thakur, A; Sharma, S; Singh, R.; Wani, A.A.; Sharon, A.; Bharatam, P.V; Kumar, R.
Microwave-promoted ring-closure reactions of 5-amino-1-(2-aminophenyl)-1H-imidazole-4-carbonitrile (7) with various mono/1,2-biselectrophiles are presented. The reaction of 7 with aldehydes, ketones and isocyanates produced the corresponding Pictet–Spengler (PS) products i.e. the imidazo[1,2-a]quinoxaline ring system via 6-endo-trig cyclisation. On the other hand, the reaction of 7 with CH(OEt)3, and CDI resulted in the formation of benzo[f]imidazo[1,5-a][1,3,5]triazepine scaffolds via a 7-exo-trig cyclisation process. The mechanistic aspects of these ring cyclisation processes have been analysed and studied to rationalise 6- versus 7-membered ring formation using density functional theory (DFT). DFT calculations revealed the involvement of N-Heterocyclic Carbene (NHC) in the PS reaction mechanism.
Exploration of Pd-catalysed four-component tandem reaction for one-pot assembly of pyrazolo[1,5-c]quinazolines as potential EGFR inhibitors
(Academic Press Inc., 2019) Ansari, A.J; Joshi, G; Yadav, U.P; Maurya, A.K; Agnihotri, V.K; Kalra, S; Kumar, R; Singh, S; Sawant, D.M.
A series of pyrazolo[1,5-c]quinazolines as EGFR inhibitors was designed and synthesized by highly efficient and novel multicomponent route involving Pd-catalyzed tandem one-pot four-component reaction. The reaction proceeds with good functional group tolerance under a simple condition with excellent regioselectivity and high efficiency. Target compounds were screened against cancer cell lines MDA-MB-231, A549 and H1299. Of these, 9b and 10b exhibited superior anticancer activity (IC50 < 2.5 ?M) to erlotinib and gefitinib. Synthetics were able to inhibit EGFR mediated kinase activity, induced ROS in cancer cells promoting mitochondrial mediated apoptosis via halting cell cycle progression at G1 phase.
Micropropagation protocol for Salvadora oleoides
(Northeast Forestry University, 2019) Kumar, R; Najar, R.A; Gupta, K.B; Saini, R.G.
Salvadora oleoides Decne. is a pharmaceutically important plant. Owing to poor seed formation, viability and, germination, and to anthropogenic disturbances, this species is on the verge of extinction. A reproducible micropropagation protocol to increase the population through tissue culture has been standardized and the results are reported here. Callus tissues were initiated from young leaves and stem explants. Leaf calluses proliferated with 1.5 mg/L BAP and 0.9 mg/L 2, 4-D with additives and continuous slow proliferation up to 15 weeks on 0.5 mg/L BAP and additives with 200 mg/L activated charcoal. Direct shoot initiation took place from stem node explants after 12 days; 4–5 shoots per node were produced in 30 days. Shoot clumps elongated and grew further on MS media supplemented with 2 mg/L BAP, 0.2 mg/L NAA and additives, which generated 20–23 shoots. The elongated shoots induced tap roots with 4 mg/L NAA and 200 mg/L activated charcoal in 12 days. In vitro raised plants produced secondary roots when transferred to pots containing vermiculite maintained at 28–35 °C. The plantlets successfully acclimatised in pots containing soil in natural conditions. © 2018, Northeast Forestry University and Springer-Verlag GmbH Germany, part of Springer Nature.
Novel 2-(substituted phenyl Imino)-5-benzylidene-4-thiazolidinones as possible non-ulcerogenic tri-action drug candidates: synthesis, characterization, biological evaluation And docking studies.
(Springer, 2019) Chawla, P.; Kalra, S; Kumar, R; Ranjit, S; Saraf, S.
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.
Pseudomonas citronellolis; a multi-metal resistant and potential plant growth promoter against arsenic (V) stress in chickpea
(Elsevier, 2019) Adhikary, Arindam; Kumar, R; Pandir,R; Bhardwaj, Pankaj; Wusirika, Ramakrishna; Kumar, Sanjeev
Soil micro-biota plays a vital role in maintaining plant growth and fitness under normal and adverse conditions. Pseudomonas is one of the most important free-living and copious genera in south-west Punjab and involved in plant growth promotion under heavy metal stress. In this study, we have studied microbial diversity of the agricultural and marginal land based on 16S rRNA gene and screened eight strains of Pseudomonas for its tolerances towards various heavy metals and for plant growth promoting properties (PGP). The best strain is tested in chickpea plants against Arsenic (As5+) stress. All the strains responded differently to heavy metals viz. Arsenic, (As5+ (0.3–0.5M) and As3+ (250 μg mL−1) Cadmium (Cd2+) (250–350 μg mL−1), Chromium (Cr2+) (200–350 μg mL−1) and Mercury (Hg2+) (1–2 μg mL−1). Out of eight strains, only two strains (KM594398 and KM594397) showed plant growth promoting characters, concurrently they were highly tolerant to Arsenic (As5+). Pseudomonas citronellolis (PC) (KM594397) showed the best results in terms of As5+ tolerance and plant growth promoting activity, hence further tested for actual plant growth response in chickpea (Cicer arietinum L.) under As5+ (10–160 mg kg−1) stress. Pseudomonas citronellolis enhanced plant growth and dry biomass under As5+ stress. High As5+ tolerance and plant growth promoting activity of Pseudomonas citronellolis in chickpea especially designate this strain suitable for marginal lands and heavy metals contaminated sites. © 2019 Elsevier Masson SAS
Quantification of groundwater-agricultural soil quality and associated health risks in the agri-intensive Sutlej River Basin of Punjab, India
(Springer, 2020) Kumar, R; Mittal, S; Peechat, S; Sahoo, P.K; Sahoo, S.K.
The quality of drinking water and agricultural soil significantly affects the health of residents of the area. The quality of groundwater used as drinking and irrigation water along with agricultural soil of an agri-intensive region of the Sutlej River Basin (SRB), Punjab (India), has been investigated in the present paper to further access their impacts on human health. The quality parameters studied are pH, conductivity, cations, anions and trace elements/heavy metals. The spatio-distribution maps of major contaminates have been made. The distribution of major existing groundwater and agricultural soil contaminants has also been illustrated using inverse distance weighting interpolation technique. Further, the Pearson correlation matrix and principal component analysis (PCA) have been applied to explore the correlation and source apportionment analysis for the contaminants. Finally, the health risk assessment study has also been performed. The results showed elevated levels [compared to BIS acceptable limits] of bicarbonate and total hardness in more than 90% groundwater samples, while the concentration of Se and U exceeded in around 25% samples. Spatial distribution maps showed a non-homologous distribution pattern for most of the heavy metals except Zn, indicating their different origins. The significant existence of Se and U in groundwater and low content in soils indicated their geogenic origin. The Gibbs diagram suggested that rock-water interaction is the primary process controlling the chemical evolution of the groundwater in the region. The PCA indicated that Cu, Mn, Pb, NO3? and SO42? in groundwater have an anthropogenic origin, whereas Fe, As and U are mainly of geogenic origin. Significant positive correlations of heavy metals with Fe and Al in soils indicated scavenging of these elements by Fe/Al-oxyhydroxides minerals. Based on SAR, Na%, PI and corrosivity ratio analysis, it can be concluded that groundwater of the region is suitable for irrigation purposes Further, health risk assessment study indicated Cr and As are the possible cancer risk posing elements from both soil and groundwater. Non-carcinogenic risk assessment showed that cumulative exposure (hazard index 1.98) of U (HQ 1.21), NO3? (HQ 0.37) and F? (HQ 0.34) might pose harmful impacts to residents through groundwater ingestion in the long term. Although currently the contaminants in the groundwater, soil system may not pose any human health risks, continuous long-term monitoring is required to keep a check on the changes in their quality with time. 2020, Springer Nature B.V.
TEQIP-II Sponsored,
(2015) Nag, S; Sharma, S; Mittal, Sunil; Kumar, R; Vishwakarma, G. S.