Browsing by Author "Manisha Malviya"

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Biosynthesis of silver nanoparticles from the novel strain of Streptomyces Sp. BHUMBU-80 with highly efficient electroanalytical detection of hydrogen peroxide and antibacterial activity
(Elsevier Ltd, 2017) Rajeev Kumar Gupta; Vijay Kumar; Ravi Kumar Gundampati; Manisha Malviya; Syed Hadi Hasan; Medicherla V. Jagannadham
The use of a microbial supernatant has become a potential source for the eco-friendly and rapid synthesis of nanoparticles. In this study, we have targeted to synthesize silver nanoparticles (AgNPs) using extracellular secretion of Streptomyces sp. The strain was successfully isolated from the soil samples and identified as Streptomyces sp. BHUMBU-80 on the basis of morphological, biochemical and Phylogenetic analysis. The synthesized AgNPs was characterized using several modern characterizing techniques such as UV-vis Spectroscopy, FTIR spectroscopy, SEM, EDX spectroscopy, TEM, XRD and XPS. The presence of characteristics SPR band at 450 nm confirmed the synthesis of AgNPs. The FTIR spectra confirmed the involvement of various functional groups present in culture supernatant responsible for the reduction of Ag+ ions into Ag0. SEM and TEM analysis confirmed the presence of spherical AgNPs with an average size of 21 ± 1 nm. The XPS analysis confirmed the presence of two individual peaks which attributed to the Ag 3d3/2 and Ag 3d5/2 binding energies corresponding to the presence of metallic silver. The electrochemical studies of the green synthesized AgNPs using a glassy carbon electrode showed the superior electrocatalytic activity towards the reduction of H2O2. The calibration plot was established for H2O2 in the concentration range from 50 μM to 1000 μM with 50 μM detection limit, at a signal-to-noise ratio of 3 in a three-electrode cell with a Pt plate as the counter electrode. Additionally, the AgNPs also showed potent antibacterial activity against pathogenic bacteria like E. coli, and S. aureus. © 2017 Elsevier Ltd. All rights reserved.
Electro-organic synthesis of isatins and hydrazones through C-N cross-coupling and C(sp2)-H/C(sp3)-H functionalization
(Royal Society of Chemistry, 2023) Neetu Verma; Rajdeep Tyagi; Ashish Khanna; Manisha Malviya; Ram Sagar
An efficient and unique approach to synthesize isatin (indole-2,3-dione) from 2-aminoacetophenone under electrochemical conditions supported by I2-DMSO through C-N cross-coupling and C(sp2)-H/C(sp3)-H functionalization is presented. This synthetic method spans a wide range of substituted 2-aminoacetophenone substrates. The use of iodine as a promoter and shorter reaction times produced good to very good yields of isatin derivatives, which is a significant improvement over the reaction in a batch process. Further, hydrazones of isatin were synthesized by using hydrazine hydrate which produces electrochemically active molecules, namely isatin-hydrazones. The hydrazones of acetophenone were also obtained using the same reaction protocol. Additionally, the effect of increasing scan rate studied using cyclic voltammetry shows that the process followed a diffusion-controlled mechanism. © 2023 The Royal Society of Chemistry.
Graphene Derived Materials as Catalysts for the Oxygen Reduction Reaction
(Bentham Science Publishers, 2022) Manisha Malviya; Amisha Soni; Sarvatej Kumar Maurya
The conventionally used electrocatalysts for oxygen reduction reaction (ORR) such as PGM and sulphide based, respectively, have contributed negligible or zero-emissions towards global warming. However, there is an urgent need to develop cost-effective, earth-abundant, efficient, non-poisonous and stable electrocatalysts. Through an exhaustive literature survey, it was observed that graphene derived materials are a promising candidate for ORR owing to exceptional electronic, physical and mechanical properties. Furthermore, the surface of graphene derived materials (GDM) can be modified to get desired physicochemical properties and induce electrocatalytic activity by adopting various synthesis methods insynthesis and postsynthesis by insertion of dopants, defect points, surface tuning, making composites, advanced wrapping structures. In the present chapter, fundamental ORR, graphene derived electrocatalysts, and the recent progress of ORR are discussed. © 2022 Bentham Science Publishers.
Liquid-assisted grinding (LAG) approach, metal-free synthesis of 2,3-dihydro-1,5-benzothiazepines and their electrochemical properties
(CSIRO, 2024) Manjit Singh; Kuldeep Kumar Maurya; Manisha Malviya
In this work, we have disclosed a facile metal-free synthesis of pharmaceutically fascinating and biologically important benzothiazepines in the presence of a few drops of ethanol. The present methodology converts chalcones and ortho-amino thiophenol into 2,3-dihydro-1,5-benzothiazepines under ambient conditions using liquid-assisted grinding, resulting in rapid synthesis in a very short period. This process is eco-friendly, operationally simple and gives good to excellent yields of products with easy isolation. This approach offers a facile synthesis of 2,3-dihydro-1,5-benzothiazepines from three readily available starting materials. An electrochemical study of the benzothiazepine derivatives was undertaken using cyclic voltammetry and electrochemical impedance spectroscopy techniques. © 2024 CSIRO. All rights reserved.
Molecular Design, Synthesis and Anti-cancer Activity of Novel Pyrazolo[3,4-b]pyridine-based Glycohybrid Molecules
(Academic Press Inc., 2025) Neetu Verma; Ghanshyam Tiwari; Ashish Khanna; Vinay Kumar Mishra; Yogesh Jawaharlal Yadav; Manisha Malviya; Ram Sagar
Molecular hybridization is an emerging strategy in medicinal chemistry for designing new bioactive molecules that link pharmacophores covalently and shows synergistic enhanced properties. Herein, we have developed pyrazolo[3,4-b]pyridine-based new glycohybrids considering the Warburg effect. A microwave-assisted, copper-catalyzed efficient synthesis of new triazole-linked glycohybrids based on pyrazolo[3,4-b]pyridines scaffold was achieved successfully in high yields with inherent stereochemical diversity from D-glucose, D-galactose, and D-mannose. The twenty-three distinct new glycohybrids, incorporating various electron-donating and electron-withdrawing groups with stereochemical diversities, were prepared using developed synthetic protocol. This efficient synthesis significantly reduced reaction time and furnished products with high isolated yields, showcasing its potential for glycohybrids synthesis. In-vitro study revealed that among the synthesized glycohybrids, compound 8e emerged as a potential compound against MDA-MB231 (SI > 31) and MCF-7 (SI > 434) with an IC50 value of 19.58 µM and 1.42 µM respectively. The molecular docking study predicts the binding interaction of the chemical probe with the target protein HCK. The enzyme inhibition assay revealed that compound 8e is having strong inhibitory potency against HCK enzyme. This article highlights the synthetic utility of this strategy and the potential applications of these newly designed and prepared glycohybrids. © 2025 Elsevier Inc.
Synthesis of imidazole-fused nitrogen-bridgehead heterocycles catalysed by lipase and their antifungal and antimicrobial bioactivity
(Royal Society of Chemistry, 2024) Manjit Singh; Manisha Malviya; Vijay B. Yadav; Aishwarya Nikhil; Munesh Gupta
An effective approach for selective C-N bond formation for synthesising imidazo[1,2-a] pyridine-based heterocycles using porcine pancreatic lipase (PPL) as a biocatalyst has been devised. Under moderate conditions, a series of imidazo[1,2-a]pyridine-based heterocycle derivatives were synthesised with remarkable selectivity in good-to-excellent yields (89-95%). Further, the antimicrobial and antifungal activities of derivatives 3ha, 3ka, 3fa, 3hc, and 3eb were observed, and they were found to be biologically active in antimicrobial susceptibility tests for Gram-positive bacteria (Enterococcus faecalis ATCC 29212 and Staphylococcus auris ATCC 25923), Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) and fungal strains (Candida albicans ATCC 90028 and Candida tropicalis ATCC 750). © 2024 The Royal Society of Chemistry.