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Item IN VITRO ANTIBACTERIAL ACTIVITY OF HIBISCUS ROSA-SINENSIS FLOWER EXTRACT AGAINST HUMAN PATHOGENS(Asian Pacific Tropical Biomedicine Press, 2012) Ruban P; Gajalakshmi K; Department of Biotechnology; Gajalakshmi KTo access the in vitro antibacterial activity of Hibiscus rosa-sinensis (H. rosa- sinensis)flower extract against human pathogens. Methods: Antibacterial activity was evaluated by using disc and agar diffusion methods. The protein was run through poly acrylmide gel electrophoresis to view their protein profile. Results: The results showed that the cold extraction illustrates a maximum zone of inhibition against Bacillus subtillis (B. subtillis), Escherichia coli (E. coli) viz., (17.00 ± 2.91), (14.50 ± 1.71) mm, followed by hot extraction against, E. coli, Salmonella sp. as (11.66 ± 3.14), (10.60 ± 3.09) mm. In methanol extraction showed a highest zone of inhibition recorded against B. subtillis, E. coli as (18.86 ± 0.18), (18.00 ± 1.63) mm pursued by ethanol extraction showed utmost zone of inhibition recorded against Salmonella sp. at (20.40 ± 1.54) mm. The crude protein from flower showed a maximum inhibitory zone observed against Salmonella sp., E. coli viz., (16.55 ± 1.16), (14.30 ± 2.86) mm. The flower material can be taken as an alternative source of antibacterial agent against the human pathogens. Conclusions: The extracts of the H. rosasinensis are proved to have potential antibacterial activity, further studies are highly need for thedrug development.Item UV-VIS ABSORPTION SPECTRA OF SN(IV)TETRAKIS(4-PYRIDYL) PORPHYRINS ON THE BASIS OF AXIAL LIGATION AND PYRIDINE PROTONATION(Springer Link, 2019-09) Pavithra, Jayachandran; Abiram, Angamuthu; Praveena, Gopalan; Department of Physics; Praveena, GopalanThe present study highlights the structural and electronic spectra of Sn(IV)tetrakis(4-pyridyl) porphyrins (SnTP) using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The impact of axial ligands (OH-, Cl-, and H2O) and protonation at pyridine sites on the excitation properties of SnTP is also explored. The considered SnTPs were optimized at B3LYP/6-31+G* level of theory with LANL2DZ basis set for Sn metal. The effects of tetrahydrofuran (THF) and dimethylformamide (DMF) solvents were also assessed employing conductor-like polarizable continuum (C-PCM) model. The observed structural effects correlate well with the experimental data and clearly depict the impact of axial ligands on the SnTP ring. The absorption spectra along with the frontier orbitals in all three phases show noticeable dependence of axial ligation on the photophysical properties of SnTPs. The transition character of molecular orbitals and their respective density of states (DOS) were explored to infer the orbitals involved in electronic transitions. Graphical abstract The structural and electronic spectra of Sn(IV)tetrakis(4-pyridyl) porphyrins (SnTP) were examined using time-dependent density functional theory (TDDFT). Axial ligation and pyridine protonation significantly affects the absorption properties of Sn complexes. The overall results suggest the application of [(OH-)Sn (OH-)TP] and [(Cl-)Sn (Cl-)TP] as photosensitizers.Item AN EFFICIENT NEW DUAL FLUORESCENT PYRENE BASED CHEMOSENSOR FOR THE DETECTION OF BISMUTH (III) AND ALUMINIUM (III) IONS AND ITS APPLICATIONS IN BIO-IMAGING(Elsevier B.V, 2019-06) Arjunan, Saravanan; Selvaraj, Shyamsivappan; Thangaraj, Suresh; Gopalan, Subashini; Krishna, Kadirvelu; Nanjan, Bhuvanesh; Raju, Nandhakumar; Palathurai, Subramaniam Mohan; Department of Chemistry; Gopalan, SubashiniA new simple pyrene based schiff base chemosensor 1 (nicotinic acid pyren-1-ylmethylene-hydrazide) has been constructed and is prepared from 1-pyrenecarboxaldehyde and nicotinic hydrazide. Notably, the chemosensor 1 exhibited remarkable colour changes while in the presence of trivalent metal ions like Bi3+ & Al3+ ion in DMSO-H2O, (1:1 v/v, HEPES = 50 mM, pH = 7.4). The UV-Vis spectral investigation of chemosensor 1 showed that the maximum absorption peak appeared at 378 nm. In emission studies, chemosensor 1 develops weak fluorescence, while upon the addition of Bi3+ and Al3+ ions, it exhibits an enhancement of fluorescence intensity. Nevertheless, rest of metal ions have no changes in the emission spectra. The association constant of chemosensor 1 for binding to Bi3+ & Al3+ system had a value of 1.27 × 104 M-1 and 1.53 × 104 M-1. The detection limits were 0.12 µM for Bi3+ and 0.17 µM for Al3+ respectively. The overall results reveal that chemosensor 1 can act as a dual-channel, highly selective, and sensitive probe for Bi3+ and Al3+ ions. Moreover, the fluorescence imaging of chemosensor 1 was applied in RAW 264.7 cell line and cytotoxicity assay prove that this chemosensor 1 is non-toxic as well as highly biocompatible.Item CORROSION INHIBITION PROPERTY OF POLYESTER-GROUNDNUT SHELL BIODEGRADABLE COMPOSITE(Elsevier Inc, 2016-12) Sounthari, P; Kiruthika, A; Saranya, J; Parameswari, K; Chitra, S; Department of Chemistry; Parameswari, K; Chitra, SThe use of natural fibers as reinforcing materials in thermoplastics and thermoset matrix composites provide optimistic environmental profits with regard to ultimate disposability and better use of raw materials. The present work is focused on the corrosion inhibition property of a polymer matrix composite produced by the use of groundnut shell (GNS) waste. Polyester (PE) was synthesized by condensation polymerization of symmetrical 1,3,4-oxadiazole and pimelic acid using sodium lauryl sulfate as surfactant. The polyester-groundnut shell composite (PEGNS) was prepared by ultrasonication method. The synthesized polyester-groundnut shell composite was characterized by FT-IR, TGA and XRD analysis. The corrosion inhibitory effect of PEGNS on mild steel in 1M H2SO4 was investigated using gravimetric method, electrochemical impedance spectroscopy, potentiodynamic polarization, atomic absorption spectroscopy and scanning electron microscopy. The results showed that PEGNS inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration and decrease with increasing temperature. The composite inhibited the corrosion of mild steel through adsorption following the Langmuir adsorption isotherm. Changes in the impedance parameters Rt, Cdl, Icorr, Ecorr, ba and bc suggested the adsorption of PEGNS onto the mild steel surface, leading to the formation of protective film.