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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.
Vijayakumar, Mayakrishnan,Ilavenil, Soundarrajan,Arasu, Mariadhas Valan,Jung, Min-Woong,Park, Hyung Soo,Kim, Ji Hea,Lim, Young Cheol,Choi, Ki Choon The Korean Society of Grassland and Forage Science 2014 한국초지조사료학회지 Vol.34 No.3
The aim of present study was to improve the quality of silage using lactic acid bacteria (LAB) and chlorella as a supplement. Italian ryegrass (IRG) mediated silage was prepared with lactic acid bacteria (L. plantarum) and different concentration of chlorella. We analyzed the nutritional profiles such as crude protein (CP), acid detergent fiber (ADF) neutral detergent fiber (NDF), total digestible nutrient (TDN) and in-vitro dry matter digestibility (IVDMD), microbial counts and fermentative acids such as lactic acid, acetic acid and butyric acid in the control and experimental silage after three months. It shows increased crude protein content and also maintains the rest of nutritional values as compared with control silage. LAB inoculation with chlorella as supplementation slightly reduced the pH of the silage. In addition, it increased the fermentative acids production as compared with control silage and inhibits the undesired microbial growth especially fungi in the silage. Therefore, we suggest that LAB inoculation and chlorella supplementation to the IRG mediated silage could be improved the nutritional quality of the silage which is an intrinsic feature for the application in the preparation of animal feeds and functional foods.
( Vijayakumar M. Malathi ),( Ravi P. More ),( Rangasamy Anandham ),( Gandhi R. Gracy ),( Muthugounder Mohan ),( Thiruvengadam Venkatesan ),( Sandipan Samaddar ),( Sushil K. Jalali ),( Tongmin Sa ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.6
Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-tophenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.
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%.
Vijayakumar, Vijayalekshmi,Nam, Sang Yong Elsevier 2019 Journal of industrial and engineering chemistry Vol.70 No.-
<P><B>Abstract</B></P> <P>Anion exchange membranes (AEMs) play prominent role in addressing alkaline fuel cell efficiency and cost. Great deal of efforts has been made in the past, particularly during the last couple of years to reach AEMs with high hydroxide conductivity, good chemical/thermal/mechanical stability, fuel cross-over resistance and low cost. The purpose of this review is to summarize and discuss the progress on the development of different AEMs for alkaline fuel cells over the last three years. The alternative AEMs based on the modified synthetic and sustainable polymers, organic/inorganic hybrid materials and additives are reviewed in the context of AEM materials.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Vijayakumar, Sekar,Saravanakumar, Kandasamy,Hu, Xiaowen,Wang, Myeong-Hyeon Plenum Press 2019 Journal of cluster science Vol.30 No.6
<P> The research for innovative antibiofilm drugs is essential due to the increased microbial resistance to antibiotics presently in use. Now a day’s natural products wrapped nano biomaterial play an important role in the field of medicine. The aqueous bark extracts of <I>Rhus verniciflua</I> was used to synthesize gold nanoparticles (Rh-AuNPs) by green method. The synthesized nanoparticles were characterized (optical property, crystallinity, functional groups, size, shape and purity) by UV-vis spectroscopy (UV), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission transmission electron microscopy (FE-TEM) with Energy dispersive X-ray (EDX). An effective antioxidant activity was observed at 100 μg/ml of Rh AuNPs. The acridine orange, live and dead (PI-SYTO-9) staining assay using confocal laser scanning microscopic, results evidanced that the Rh-AuNPs (100 μg/ml) was effectively inhibited the biofilms of <I>Escherichia coli</I> and <I>Staphylococcus aureus.</I> In addition, Rh-AuNPs also significantly inhibited the cell surface hydrophobicity of both <I>E. coli</I> and <I>S. aureus</I> at 100 μg/ml. This study reports antibacterial potency of Rh-AuNPs and that have significant therapeutic properties. </P>
Vijayakumar, Vijayalekshmi,Kim, Kihyun,Nam, Sang Yong The Korean Society of Industrial and Engineering C 2019 공업화학 Vol.30 No.6
Polybenzimidazole (PBI), an engineering polymer with well-known excellent thermal, chemical and mechanical stabilities has been recognized as an alternative to high temperature polymer electrolyte membranes (HT-PEMs). This review focuses on recent advances made on the development of PBI-based HT-PEMs for fuel cell applications. PBI-based membranes discussed were prepared by various strategies such as structural modification, cross-linking, blending and organic-inorganic composites. In addition, intriguing properties of the PBI-based membranes as well as their fuel cell performances were highligted.
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>