Publications by authors named "Vediappen Padmini"

15 Publications

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Small molecule induced toxic human-IAPP species characterized by NMR.

Chem Commun (Camb) 2020 Nov 2;56(86):13129-13132. Epub 2020 Oct 2.

Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.

In this study, the effect of CurDAc, a water-soluble curcumin derivative, on the formation and stability of amyloid fibers is revealed. CurDAc interaction with amyloid is structurally selective, which is reflected in a strong interference with hIAPP aggregation while showing weaker interactions with human-calcitonin and amyloid-β in comparison. Remarkably, CurDAc also exhibited potent fiber disaggregation for hIAPP generating a toxic oligomeric species.
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http://dx.doi.org/10.1039/d0cc04803hDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7641245PMC
November 2020

Highly Selective and Sensitive Colorimetric and Fluorimetric Sensor for Cu.

J Fluoresc 2020 Jan;30(1):3-10

Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, 625021, Madurai, Tamilnadu, India.

A newly designed fluorescent and colorimetric probe was synthesized and selective detection of cu was successful in aqueous medium. The design strategy exhibited strongly fluorescent when binding with cu based on the change in structure between spirocyclic to a non-cyclic form of rhodamine based dye. The UV visible spectra of probe (6GS2) exhibited three absorption peaks at 229, 309 and 530 nm respectively. The emission spectra of fluorescent probe exhibited wavelength at 550 nm. The peak intensity increases during the addition of copper ion to probe through n-π transition. The probe characterized by different techniques like NMR, absorption, emission, mass and test strips methods. Graphical Abstract .
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http://dx.doi.org/10.1007/s10895-019-02450-9DOI Listing
January 2020

Highly Efficient Colorimetric Sensor for Selective and Sensitive Detection of Arsenite Ion (III) in Aqueous Medium.

J Fluoresc 2019 Jul 21;29(4):813-818. Epub 2019 Jun 21.

Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai, Tamilnadu, 625021, India.

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http://dx.doi.org/10.1007/s10895-019-02401-4DOI Listing
July 2019

Synthesis of β-Ketoamide Curcumin Analogs for Anti-Diabetic and AGEs Inhibitory Activities.

Chem Biodivers 2018 Aug 19;15(8):e1800105. Epub 2018 Jul 19.

Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai, Tamil Nadu, India.

Two different series of novel β-ketoamide curcumin analogs enriched in biological activities have been synthesized. The synthesized compounds were screened for their in vitro anti-diabetic and AGEs inhibitory activities and exhibited potent to good anti-diabetic and AGEs inhibitory activities. The molecular docking study was also performed with the α-amylase enzyme.
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http://dx.doi.org/10.1002/cbdv.201800105DOI Listing
August 2018

I-Catalyzed Oxidative Cross-Coupling Reaction of Methyl Ketones and 2-(2-Aminophenyl) Benzimidazole: Facile Access to Benzimidazo[1,2-]quinazoline.

ACS Omega 2018 May 8;3(5):5021-5028. Epub 2018 May 8.

Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.

A general and efficient iodine-catalyzed metal-free oxidative cross-coupling reaction of methyl ketones with 2-(1-benzo[]imidazol-2-yl)aniline has been established. This is a new synthetic strategy for the synthesis of benzimidazo[1,2-]quinazoline derivatives involving C(sp)-H oxidation, condensation, and cyclization processes.
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http://dx.doi.org/10.1021/acsomega.8b00067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6641929PMC
May 2018

Curcumin based chemosensor for selective detection of fluoride and cyanide anions in aqueous media.

Photochem Photobiol Sci 2016 Nov;15(12):1536-1543

Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625021, Tamilnadu, India.

The conjugate N,N-dimethyl curcumin analogue fluorophore dye 1 has been synthesized and its performance as a sensor was demonstrated. As a fluoride and cyanide sensor it enabled visual detection, and showed changes in UV-vis and fluorescence spectra in the presence of fluoride and cyanide ions in aqueous medium. The Job's plot indicated that the formation of a complex between dye-1 fluoride ions has a 1 : 1 stoichiometric ratio.
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http://dx.doi.org/10.1039/c6pp00254dDOI Listing
November 2016

Evaluation of antimicrobial activity of glycinate and carbonate derivatives of cholesterol: Synthesis and characterization.

Saudi Pharm J 2016 Nov 1;24(6):658-668. Epub 2015 Jun 1.

Department of Organic Chemistry, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India.

A series of glycinate and carbonate derivatives of cholesterol were synthesized, characterized and assessed for their antimicrobial activity. Our results revealed that the compounds exerted inhibitory activities against gram-negative bacteria and fungi.
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http://dx.doi.org/10.1016/j.jsps.2015.05.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5094438PMC
November 2016

Multiple biological activities and molecular docking studies of newly synthesized 3-(pyridin-4-yl)-1H-pyrazole-5-carboxamide chalcone hybrids.

Bioorg Med Chem Lett 2016 12 27;26(23):5624-5630. Epub 2016 Oct 27.

Department of Organic Chemistry, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India. Electronic address:

A series of fifteen new chemical entities, 3-(pyridin-4-yl)-1H-pyrazole-5-carboxamide chalcones (6a-o), were synthesized as new hybrids with enriched biological activities compared to their parent molecules. The compounds were characterized by H NMR, C NMR, Mass and IR spectral studies. Their antibacterial, anti-inflammatory and antioxidant activities have been evaluated. These compounds showed moderate to good antibacterial, anti-inflammatory and antioxidant activities. The molecular docking analysis was performed with cyclooxygenase enzyme to ascertain the probable binding model.
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http://dx.doi.org/10.1016/j.bmcl.2016.10.075DOI Listing
December 2016

Optically Biaxial, Re-entrant and Frustrated Mesophases in Chiral, Non-symmetric Liquid Crystal Dimers and Binary Mixtures.

Chem Asian J 2016 Oct 6;11(20):2897-2910. Epub 2016 Sep 6.

Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Prof. U. R. Rao Road, Jalahalli, Bengaluru 560013, India.

Sixteen optically active, non-symmetric dimers, in which cyanobiphenyl and salicylaldimine mesogens are interlinked by a flexible spacer, were synthesized and characterized. While the terminal chiral tail, in the form of either (R)-2-octyloxy or (S)-2-octyloxy chain attached to salicylaldimine core, was held constant, the number of methylene units in the spacer was varied from 3 to 10 affording eight pairs of (R & S) enantiomers. They were probed for their thermal properties with the aid of orthoscopy, conoscopy, differential scanning calorimetry and X-ray powder diffraction. In addition, the binary mixture study was carried out using chiral and achiral dimers with the intensions of stabilizing optically biaxial phase/s, re-entrant phases and important phase sequences. Notably, one of the chiral dimers as well as some mixtures exhibited a biaxial smectic A (SmA ) phase appearing between a uniaxial SmA and a re-entrant uniaxial SmA phases. The mesophases such as chiral nematic (N*) and frustrated phases viz., blue phases (BPs) and twist grain boundary (TGB) phases, were also found to occur in most of the dimers and mixtures. X-ray diffraction studies revealed that the dimers possessing oxybutoxy and oxypentoxy spacers show interdigitated (SmA ) phase where smectic periodicity is over 1.4 times the molecular length; whereas in the intercalated SmA (SmA ) phase formed by a dimer having oxydecoxy spacer the periodicity was found to be approximately half the molecular length. The handedness of the helical structure of the N* phases formed by two enantiomers was examined with the aid of CD measurements; as expected, these enantiomers showed optical activities of equal magnitudes but with opposite signs. Overall, it appears that the chiral dimers and mixtures presented herein may serve as model systems in design and developing novel materials exhibiting the apolar SmA phase possessing D symmetry and nematic-type biaxiality.
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http://dx.doi.org/10.1002/asia.201600918DOI Listing
October 2016

Chemodivergent, One-Pot, Multi-Component Synthesis of Pyrroles and Tetrahydropyridines under Solvent- and Catalyst-Free Conditions Using the Grinding Method.

ACS Comb Sci 2016 05 18;18(5):236-42. Epub 2016 Apr 18.

Department of Chemistry, Texas A&M University , College Station, Texas 77842, United States.

A highly efficient, chemoselective synthesis of a library of polysubstituted pyrroles and tetrahydropyridines has been achieved through the one-pot, multicomponent reactions of ethyl (E)-3-(aryl/alkyl amino) acrylates, 2,2-dihydroxy-1-arylethan-1-ones, and malononitrile under solvent- and catalyst-free grinding conditions. The selective formation of pyrrole or tetrahydropyridines relied on substitution of the N-aryl of ethyl (E)-3-(4-arylamino) acrylates. These reactions presumably occurred via a domino Knoevenagel condensation and Michael addition followed by an intramolecular cyclization sequence of reactions in a single transformation.
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http://dx.doi.org/10.1021/acscombsci.5b00154DOI Listing
May 2016

Biological evaluation and molecular docking studies of new curcuminoid derivatives: Synthesis and characterization.

Bioorg Med Chem Lett 2016 Apr 23;26(7):1655-9. Epub 2016 Feb 23.

Department of Microbial Technology, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India.

In the present study, three series of dimethylamino curcuminoids viz. 4-phenylaminomethyl curcumin (3a-d), arylidene curcumin (3e) and pyrazole curcumin (3f-i) derivatives have been synthesized and studied for their in vitro anti-inflammatory, antioxidant and antibacterial activities. Synthesized dimethylamino curcuminoid derivatives namely 3d, 3e, 3h and 3i have shown potent anti-inflammatory properties than parent curcumin. Molecular docking interactions of dimethylamino curcuminoids derivatives against cyclooxygenase enzymes (COX-1 and COX-2) were studied.
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http://dx.doi.org/10.1016/j.bmcl.2016.02.066DOI Listing
April 2016

A green and efficient protocol for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives via a one-pot, four component reaction by grinding method.

J Adv Res 2015 Nov 25;6(6):975-85. Epub 2014 Nov 25.

X-ray Diffraction Laboratory, Department of Chemistry, Texas A&M University, College Station, TX 77842, USA.

An efficient grinding protocol for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives from acetylene ester, hydrazine hydrate, aryl aldehydes and malononitrile under solvent free conditions has been achieved with excellent yields. The structures of the synthesized compounds were deduced by spectroscopic techniques and the compounds were further evaluated for their in vitro antioxidant and antimicrobial activities.
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http://dx.doi.org/10.1016/j.jare.2014.11.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642161PMC
November 2015

Influence of a curcumin derivative on hIAPP aggregation in the absence and presence of lipid membranes.

Chem Commun (Camb) 2016 Jan;52(5):942-5

Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA. and Biophysics Program, University of Michigan, Ann Arbor, MI 48109, USA.

The deposition of aggregates of human islet amyloid polypeptide (hIAPP) has been correlated with the death of β-cells in type II diabetes mellitus. The actual molecular mechanism of cell death remains largely unknown; however, it has been postulated that the process of aggregation from monomeric hIAPP is closely involved. A possible cause of cellular toxicity may be through the disruption of structural integrity of the cell membrane by IAPP. Herein, a water-soluble curcumin derivative, CurDAc, is used to investigate the mitigation of hIAPP aggregation in the absence and presence of lipid membrane.
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http://dx.doi.org/10.1039/c5cc07792cDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4703533PMC
January 2016

Synthesis and biological evaluation of new symmetric curcumin derivatives.

Bioorg Med Chem Lett 2015 Oct 30;25(19):4282-6. Epub 2015 Jul 30.

Department of Organic Chemistry, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India. Electronic address:

A series of novel curcumin bisacetamides aiming of enriching their biological activities have been synthesized. The synthesized compounds were screened for their in vitro antioxidant, anti-inflammatory and cytotoxic activities. All the compounds exhibited potent to good anti-inflammatory, antioxidant and noteworthy cytotoxic activities.
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http://dx.doi.org/10.1016/j.bmcl.2015.07.088DOI Listing
October 2015

Inhibitory Activity Of Curcumin Derivatives Towards Metal-free And Metal-induced Amyloid-β Aggregation.

Curr Alzheimer Res 2015 ;12(5):415-23

Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689- 798, Korea.

When Alzheimer's disease (AD) progresses, several pathological features arise including accumulation of misfolded protein aggregates [e.g., amyloid-β (Aβ) plaques], metal ion dyshomeostasis, and oxidative stress. These characteristics are recently suggested to be interconnected through a potential factor, metal-associated Aβ (metal-Aβ) species. The role of metal-Aβ species in AD pathogenesis remains unclear, however. To elucidate the contribution of metal-Aβ species to AD pathology, as well as to develop small molecules as chemical tools and/or theranostic (therapeutic and diagnostic) agents for this disease, curcumin (Cur), a natural product from turmeric, and its derivatives have been studied towards both metal-free and metal-induced Aβ aggregation. Although Cur has indicated anti-amyloidogenic activities and antioxidant properties, its biological use has been hindered due to low solubility and stability in physiologically relevant conditions. Herein, we report the reactivity of Cur and its derivatives (Gd-Cur, a potential multimodal Aβ imaging agent; Cur-S, a water soluble derivative of Cur that has substitution at the phenolic hydroxyls) with metal-free Aβ and metal-Aβ species. Our results and observations indicate that Gd-Cur could modulate Cu(II)-triggered Aβ aggregation more noticeably over metal-free or Zn(II)-induced analogues; however, Cur-S was not observed to noticeably modulate Aβ aggregation with and without metal ions. Overall, our studies present information that could aid in optimizing the molecular scaffold of Cur for the development of chemical tools or theranostics for metal-Aβ species.
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http://dx.doi.org/10.2174/1567205012666150504150125DOI Listing
February 2016