Activity Guided Isolation of Antioxidant Tannoid Principles from Anogeissus latifolia

Raghavan Govindarajan1*,Madhavan Vijayakumar1,,Annie Shirwaikar2,,Ajay Kumar Singh Rawat1,,Shanta Mehrotra1,,Palpu Pushpangadan1 한국생약학회 2005 Natural Product Sciences Vol.11 No.3

Oxidative stress is an important causative factor in several human chronic diseases, such asatherosclerosis, cardiovascular disorders, mutagenesis, cancer, several neurodegenerative disorders, and the agingprocess. Phenolics and tannins are reported to be good antioxidants. Anogeissus latifolia (Combretaceae) bark hasnot available till date. Hence the present study was undertaken to isolate antioxidant compounds by activity-guided isolation. Inhibtion of diphenyl picryl hydrazyl (DPH) and Xanthine oxidase along with photoc-hemiluminescence assay were used as bioassay for antioxidant activity. Activity guided isolation was carried outusing silica column and the compounds were quantified using HPLC. Ethyl acetate and butanol fraction exhibitedpotent antioxidant activity. Bioassay-guided isolation led to isolation of ellagic acid (1) and dimethyl ellagic acid(2these three major tannoid principles present in A. latifolia, are responsible for the antioxidant potential andpossibly their therapeutic potential.

In vitro Antioxidant Activity of Ethanolic Extract of Chlorophytum borivilianum

R. Govindarajan1,,N. Sreevidya1,,M. Vijayakumar1,,M. Thakur2,,V.K. Dixit2,,S. Mehrotra*1,,P. Pushpangadan1 한국생약학회 2005 Natural Product Sciences Vol.11 No.3

Chlorophytum borivilianum Baker (Antharicaceae) comonly referred as ‘Safed Musli’ has beenwidely used in the Indian traditional systems of medicine to treat various diseases like rheumatism apart fromaphordisiac properties. C. borivilianum was screened for the first time to determine its antioxidant activity,isolation of the sapogenins and standardization of the isolated sapogenin fraction using HPTLC. Potent antioxidantactivity of ethanolic extract was found by their ability to scavenge DPPH (84.51%), hydroxyl radical (48.95 %),feryl bi-pyridyl complex (84.53%) along with the inhibition of lipid peroxidation (67.17%) at 100g/mlconcentration. The ethanolic extract also exhibited significant inhibition of superoxide anion radical generated byplant in the traditional system especially its use as a Rasayana drug.

Glutathione Transferases Superfamily: Cold-Inducible Expression of Distinct <i>GST</i> Genes in <i>Brassica oleracea</i>

Vijayakumar, Harshavardhanan,Thamilarasan, Senthil Kumar,Shanmugam, Ashokraj,Natarajan, Sathishkumar,Jung, Hee-Jeong,Park, Jong-In,Kim, HyeRan,Chung, Mi-Young,Nou, Ill-Sup MDPI 2016 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.17 No.8

<P>Plants, as sessile organisms, can suffer serious growth and developmental consequences under cold stress conditions. Glutathione transferases (GSTs, EC 2.5.1.18) are ubiquitous and multifunctional conjugating proteins, which play a major role in stress responses by preventing oxidative damage by reactive oxygen species (ROS). Currently, understanding of their function(s) during different biochemical and signaling pathways under cold stress condition remain unclear. In this study, using combined computational strategy, we identified 65 <I>Brassica oleracea</I> glutathione transferases (<I>BoGST</I>) and characterized them based on evolutionary analysis into 11 classes. Inter-species and intra-species duplication was evident between <I>BoGST</I>s and <I>Arabidopsis</I> GSTs. Based on localization analyses, we propose possible pathways in which <I>GST</I> genes are involved during cold stress. Further, expression analysis of the predicted putative functions for <I>GST</I> genes were investigated in two cold contrasting genotypes (cold tolerance and susceptible) under cold condition, most of these genes were highly expressed at 6 h and 1 h in the cold tolerant (CT) and cold susceptible (CS) lines, respectively. Overall, <I>BoGSTU19</I>, <I>BoGSTU24</I>, <I>BoGSTF10</I> are candidate genes highly expressed in <I>B. oleracea</I>. Further investigation of GST superfamily in <I>B. oleracea</I> will aid in understanding complex mechanism underlying cold tolerance in plants.</P>

A Palm Vein Recognition System based on a Support Vector Machine

Vijayakumar Ponnusamy,Abhijit Sridhar,Arun Baalaaji,M. Sangeetha 대한전자공학회 2019 IEIE Transactions on Smart Processing & Computing Vol.8 No.1

Palm vein authentication is among the recent research in the field of access control applications. Because palm veins are tough to forge, they act as a reliable metric in security applications. Accurate extraction of palm veins is challenging in the presence of various dynamics, such as variant light conditions, variations in palm vein patterns from person to person, the cleanliness of the hand, etc. This paper presents a robust recognition process that makes use of a ridge filter for vein pattern extraction, and local binary patterns (LBP) for feature extraction. The ridge filter takes the major eigenvalue of the Hessian matrix, which contains the second-order derivative of the image pixels. The eigenvalue is then processed using LBP feature extraction from the vein patterns. Finally, a support vector machine is used for classification of subsequent images. The result shows that the system can provide accuracy of 89%, with a computation time of 0.423s. The false acceptance rate and false rejection rate were also evaluated as benchmark parameters, which show significantly good performance.

A Review on Peripheral Tinnitus, Causes, and Treatments from the Perspective of Autophagy

Vijayakumar Karthikeyan A,조광원,Maharajan Nagarajan,Jang Chul Ho 한국뇌신경과학회 2022 Experimental Neurobiology Vol.31 No.4

Tinnitus is the perception of phantom noise without any external auditory sources. The degeneration of the function or activity of the peripheral or central auditory nervous systems is one of the causes of tinnitus. This damage has numerous causes, such as loud noise, aging, and ototoxicity. All these sources excite the cells of the auditory pathway, producing reactive oxygen species that leads to the death of sensory neural hair cells. This causes involuntary movement of the tectorial membrane, resulting in the buzzing noise characteristic of tinnitus. Autophagy is an evolutionarily conserved catabolic scavenging activity inside a cell that has evolved as a cell survival mechanism. Numerous studies have demonstrated the effect of autophagy against oxidative stress, which is one of the reasons for cell excitation. This review compiles several studies that highlight the role of autophagy in protecting sensory neural hair cells against oxidative stress-induced damage. This could facilitate the development of strategies to treat tinnitus by activating autophagy.

Adsorption Characteristics of Rhodamine B from Aqueous Solution onto Baryte

Vijayakumar, G.,Yoo, C. K.,Elango, K. G.,Dharmendirakumar, M. JOHN WILEY SONS, LTD 2010 CLEAN Vol.38 No.2

Cu-Zn-Co oxide nanoflakes on Ni-foam as a binder free electrode for energy storage applications

Vijayakumar, Subbukalai,Lee, Seong-Hun,Nagamuthu, Sadayappan,Ryu, Kwang-Sun Elsevier 2018 Materials letters Vol.219 No.-

<P><B>Abstract</B></P> <P>Cu-Zn-Co oxide nanoflakes were grown on Ni-foam using a hydrothermal method. FESEM revealed a thin nanoflake-like morphology. The Cu-Zn-Co oxide nanoflakes exhibited a maximum specific capacity of 215 C g<SUP>−1</SUP> at a scan rate of 5 mV s<SUP>−1</SUP> and 178 C g<SUP>−1</SUP> at a specific current of 1 A g<SUP>−1</SUP>. When used as a Li-ion battery electrode, the Cu-Zn-Co oxide nanoflakes exhibited a specific discharge capacity of 1117 mA h g<SUP>−1</SUP> in the second cycle with excellent cycling stability. This superior cycling stability of the Cu-Zn-Co oxide nanoflakes was attributed to the direct attachment of Cu-Zn-Co oxide nanoflakes on Ni-foam.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Cu-Zn-Co oxide grown on Ni-foam shows thin nanoflake like morphology. </LI> <LI> Cu-Zn-Co oxide nanoflakes exhibits a maximum specific capacity of 215 C g<SUP>−1</SUP>. </LI> <LI> Cu-Zn-Co oxide nanoflakes exhibits a specific discharge capacity of 1603 mA h g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Performance of a knight tour parallel algorithm on multi-core system using openmp

Vijayakumar Sangamesvarappa,Vidyaathulasiraman 한국전산응용수학회 2023 Journal of applied mathematics & informatics Vol.41 No.6

Today’s computers, desktops and laptops were build with multi-core architecture. Developing and running serial programs in this multi-core architecture fritters away the resources and time. Parallel programming is the only solution for proper utilization of resources available in the modern computers. The major challenge in the multi-core environment is the designing of parallel algorithm and performance analysis. This paper describes the design and performance analysis of parallel algorithm by taking the Knight Tour problem as an example using OpenMP interface. Comparison has been made with performance of serial and parallel algorithm. The comparison shows that the proposed parallel algorithm achieves good performance compared to serial algorithm.

New Liquid Crystal-Embedded PVdF-co-HFP-Based Polymer Electrolytes for Dye-Sensitized Solar Cell Applications

Vijayakumar, G.,Lee, Meyoung-Jin,Song, Myung-Kwan,Jin, Sung-Ho,Lee, Jae-Wook,Lee, Chan-Woo,Gal, Yeong-Soon,Shim, Hyo-Jin,Kang, Yong-Ku,Lee, Gi-Won,Kim, Kyung-Kon,Park, Nam-Gyu,Kim, Suhk-Mann The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.12

Liquid crystal (LC; E7 and/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine ($I_2$), which participate in the $I_3^-/I^-$ redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and volatilization. DSSCs, with liquid crystal(LC)-embedded PVdF-co-HFP-based polymer electrolytes between the amphiphilic ruthenium dye N719 absorbed to the nanocrystalline $TiO_2$ photoanode and the Pt counter electrode, were fabricated. These DSSCs displayed enhanced redox couple reduction and reduced charge recombination in comparison to that fabricated from the conventional PVdF-co-HFP-based polymer electrolyte. The behavior of the polymer electrolyte was improved by the addition of optimized amounts of plasticizers, such as ethylene carbonate (EC) and propylene carbonate (PC). The significantly increased short-circuit current density ($J_{sc}$, $14.60\;mA/cm^2$) and open-circuit voltage ($V_{oc}$, 0.68 V) of these DSSCs led to a high power conversion efficiency (PCE) of 6.42% and a fill factor of 0.65 under a standard light intensity of $100\;mW/cm^2$ irradiation of AM 1.5 sunlight. A DSSC fabricated by using E7-embedded PVdF-co-HFP-based polymer electrolyte exhibited a maximum incident photon-to-current conversion efficiency (IPCE) of 50%.

CuCo₂O₄ flowers/Ni-foam architecture as a battery type positive electrode for high performance hybrid supercapacitor applications

Vijayakumar, Subbukalai,Nagamuthu, Sadayappan,Ryu, Kwang-Sun Elsevier 2017 ELECTROCHIMICA ACTA Vol.238 No.-

<P><B>Abstract</B></P> <P>The battery type CuCo<SUB>2</SUB>O<SUB>4</SUB> electrode was evaluated as a positive electrode material for its hybrid supercapacitor applications. CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers were prepared on Ni-foam through a simple hydrothermal process and post calcination treatment. The structure and morphology of the CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers/Ni-foam was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy. FESEM clearly revealed the flower-like morphology, which was composed of large number of petals. The length and width of the petals ranged from approximately 5–8μm and approximately 50–150nm, respectively. The CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers/Ni-foam electrode was employed for electrochemical characterization for hybrid supercapacitor applications. The specific capacity of the CuCo<SUB>2</SUB>O<SUB>4</SUB> flower-like electrode was 692.4Cg<SUP>−1</SUP> (192.3mAhg<SUP>−1</SUP>) at a scan rate of 5mVs<SUP>−1</SUP>. The flower-like CuCo<SUB>2</SUB>O<SUB>4</SUB> electrode exhibited a maximum specific capacity of 645.1Cg<SUP>−1</SUP> (179.2mAhg<SUP>−1</SUP>) at a specific current of 1Ag<SUP>−1</SUP> and good long term cyclic stability. The high specific capacity, good cyclic stability, and low internal and charge transfer resistance of the CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers/Ni-foam electrode confirmed the suitability of the prepared material as a positive electrode for hybrid supercapacitor applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This paper reports the hydrothermal preparation of CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers on Ni-foam. </LI> <LI> The CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers exhibits maximum specific capacity of 645.1Cg<SUP>−1</SUP>. </LI> <LI> After 2000 cycles, 109% of the initial specific capacity was retained. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The Ni- foam supported CuCo<SUB>2</SUB>O<SUB>4</SUB> flowers exhibits a high specific capacity with superior long term cyclic stability.</P> <P>[DISPLAY OMISSION]</P>