Ph.D Theses

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Browsing Ph.D Theses by Subject "Biochemistry"

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    In planta assimilation and characterization of metal nanoparticles in in vitro shoots of Withania somnifera and its therapeutic evaluation using Rotenone induced SH-SY5Y cells
    (Avinashilingam, 2024-08) Kanimozhi N; Dr. Kalaiselvi Senthil
    Withania somnifera is a predominant medicinal herb having economically valuable secondary metabolites and high reduction potential. Apart from being medicinal, W. somnifera also has hyper accumulation capability especially with heavy metals. Initially, metal bioaccumulation and metal reduction capability of field grown shoot tissues of W. somnifera was analysed using elemental analysis and extract based green synthesis of silver nanoparticles. The capability of W. somnifera to grow under the influence of heavy metal stress and accumulation of secondary metabolites is studied using in vitro shoot cultures. On confirmation of metal reduction capability, 45-days old in vitro shoot cultures were treated with different concentrations of silver nitrate and lead acetate salts at acute and chronic conditions. An Increase in biomass, primary and secondary metabolites (withanolides) was found to be accumulated in considerable amounts in metal salts treated in vitro shoots compared to in vitro control. Among the metal treated shoots, 1mM AgNO3 treatment for 12 days period and 0.8mM PbAc treatment for 12 days period was selected as the optimum treatment conditions and selected for the further studies. Optimum AgNO3 and PbAc treated shoots along with control shoots were analysed for its respective metal content using ICP MS analysis. The concentration of Ag in optimum AgNO3 treated shoot is 50.8ppm and Pb in optimum PbAc treated shoot is 405ppm. The nature of Ag and Pb within the shoot was analysed by TEM with EDAX analysis. The presence of Ag and Pb nanoparticles in spherical and rod shape was confirmed. In addition, the neuroprotective activity of metal treated IVS along with field grown tissues of W. somnifera was studied using Parkinson’s disease cell model (SH-SY5Y cells). Compared to field grown tissues, AgNO3 treated IVS exhibited increased neuroprotective activity against rotenone toxicity. Molecular docking study was conducted to analyse the binding site of rotenone and selected withanolides in mitochondrial complex I protein. Multiple ligand simultaneous docking revealed a binding of rotenone with withaferin A leaves complex I protein uninhibited. Thus, from the current study, we conclude that AgNO3 treated IVS along with increased withaferin A content has higher neuroprotective activity which may be used as a potential drug for toxins induced PD.
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    Neuroprotective effect of synthesized zinc oxide nanoparticle - capped catechin
    (Avinashilingam, 2024-06) Nandhini B; Dr. Anitha Subash
    Nanotechnology is a prolonged branch of existing research that involves the fabrication and customization of particle structures with typical sizes of less than 100 nm. A large area of surface-to-volume ratio was related to minimum surface functionalization, resulting in nanostructured metal oxide nanoparticles with outstanding biological activity. The biosynthesis of nanoparticles has become an important research area because of their remarkable environmental friendliness and biocompatibility. Catechin, a group of polyphenolic compounds is widely used as nutraceuticls, Zinc oxide in the form of nanoparticles, can enhance beneficial therapeutic effects to the development of nanotechnology shown to have neurogenic and neuroprotective effects, regeneration and repair of damaged brain tissue, cortical neurons synaptic connection and synaptic plasticity and ultimately promote regeneration. Camellia sinensis is one of the most popular plants used in green tea production worldwide, which possesses the antioxidant and neuroprotective properties. The aim of this research is the synthesized zinc oxide nanoparticle-capped catechin and investigation of their neuroprotective potential. Zinc oxide nanoparticles synthesized form the Camellia sinensis leaf extract by nano precipitation method, then capped with catechin. The nanoparticles were characterized by different techniques, such as UV Vis spectrophotometer, Scanning electron microscopy, Zeta potential, Fourier transform infrared spectroscopy and X-ray diffraction analysis. Synthesized zinc oxide nanoparticle-capped catechin exhibited the antioxidant activity was determined using the DPPH radical scavenging activity. Synthesized zinc oxide nanoparticle-capped catechin has significantly inhibited the acetylcholinesterase activity. A dose-dependent cell viability of synthesized zinc oxide nanoparticle-capped catechin has been observed against Neuro 2a cells. . Key words: Zinc oxide nanoparticles, catechin, Camellia sinensis, neuro 2a cells, neuroprotective, antioxidant, acetylcholinesterase