Faculty of Applied Sciences
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Item Palladium immobilized on guanidine functionalized magnetic nanoparticles : a highly effective and recoverable catalyst for ultrasound aided Suzuki-Miyaura cross-coupling reactions(Royal Society of Chemistry (RSC), 2023-10-16) Hegde, Sumanth; Nizam, Aatika; Vijayan, Ajesh; Dateer, Ramesh B.; Krishna, Suresh Babu NaiduWe designed and prepared a palladium catalyst that can be magnetically recyclable by anchoring guanidine moiety on the surface of Fe3O4 nanoparticles, named Fe3O4@SiO2-TCT-Gua-Pd. It was established to be a potent catalyst for the Suzuki–Miyaura cross-coupling reaction (SMCR) in the EtOH/ H2O system under ultrasonic conditions. FT-IR spectroscopy, field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) microanalysis, vibration sample magnetometry (VSM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses were used to characterize the structure of the Fe3O4@SiO2-TCT-Gua-Pd nanoctalyst. The Fe3O4@SiO2-TCT Gua-Pd catalyst produced favorable coupled products with excellent yields and was harmonious with various aryl halides and aryl boronic acids. The stability, low palladium leaching, and heterogeneous nature of the nanocatalyst were confirmed by a hot-filtration test. The palladium nanocatalyst could be easily recovered by magnetic field separation and recycled at least 6 times in a row without noticeable loss in its catalytic activity.Item Biogenic synthesis of zinc oxide nanoparticles mediated by the extract of Terminalia catappa fruit pericarp and its multifaceted applications(American Chemical Society (ACS), 2023-10-09) Fernandes, Cannon Antony; Jesudoss M, Nameeta; Nizam, Aatika; Krishna, Suresh Babu Naidu; Lakshmaiah, Vasantha VeerappaZinc oxide nanoparticles (ZnO-NPs) were bio synthesized by using the pericarp aqueous extract from Terminalia catappa Linn. These NPs were characterized using various analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV) spec troscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM), and XRD studies of the nanoparticles reported mean size as 12.58 nm nanocrystals with highest purity. Further SEM analysis emphasized the nanoparticles to be spherical in shape. The functional groups responsible for capping and stabilizing the NPs were identified with FTIR studies. DLS studies of the synthesized NPs reported ζ potential as −10.1 mV and exhibited stable colloidal solution. These characterized ZnO-NPs were evaluated for various biological applications such as antibacterial, antifungal, antioxidant, genotoxic, biocompatibility, and larvicidal studies. To explore its multidimensional application in the field of medicine. NPs reported a potential antimicrobial activity at a concentration of 200 μg/mL against bacterial strains in the decreasing order of Streptococcus pyogenes > Streptococcus aureus > Streptococcus typhi > Streptococcus aeruginosa and against the fungi Candida albicans. In vitro studies of RBC hemolysis with varying concentrations of NPs confirm their biocompatibility with IC50 value of 211.4 μg/mL. The synthesized NPs’ DPPH free radical scavenging activity was examined to extend their antioxidant applications. The antiproliferation and genetic toxicity were studied with meristematic cells of Allium cepa reported with mitotic index (MI index) of 1.2% at the concentration of 1000 μg/mL. NPs exhibited excellent Larvicidal activity against Culex quinquefasciatus larvae with the highest mortality rate as 98% at 4 mg/L. Our findings elicit the therapeutic potentials of the synthesized zinc oxide NPsItem Differential approach of bioremediation by sclerotium rolfsii towards textile dye(2023-10-05) Samuel, Anthony; Lakshmaiah, , Vasantha Veerappa; Dias, Priyanjali; Praveen, N.; Fernandes, Cannon Antony; Nizam, Aatika; Krishna, Suresh Babu NaiduSynthetic dyes are extensively used in various industries and are one of the major contaminants of industrial effluents. Dyes being xenobiotic, carcinogenic, and toxic there is need for their effective removal and detoxification to conserve water resources. Tremendous research has been carried out to identify potent microorganisms that facilitate bioremediation of these harmful dyes. A static batch culture has proved white rot fungi Sclerotium.rolfsii as an efficient catalyst in bioremediation of textile dyes and to compare their efficiency in decolourisation of two different azo dyes. Studies revealed the organism employ different remedial approach to cationic dye (Malachite green) and anionic dyes (Rose Bengal). Decolourisation of malachite green was a gradual with degradation and bio-transformation to colourless, non-toxic by products while Decolourisation of rose Bengal was quick process of biosorption. S.rolfsii exhibited 89% of decolourisation of malachite green dyes at higher concentration of 900mg/L while 96% for rose Bengal at 900mg/L. The mechanism of dye decolourisation was proposed using the UV Vis spectrophotometry, FTIR, XRD, HPLC and SEM. Microbial toxicity studies confirmed the dye metabolites of degraded malachite green was less toxic compared to original dye. Com- prehensively studies illustrate the sustained application of S. rolfsii as model organism for bioremediation of complex industrial effluents due to its differential bio remedial approach can potentially decolourise or remove various dyes.Item Multicomponent synthesis strategies, catalytic activities, and potential therapeutic potential of pyranocoumarins : a comprehensive review(Wiley, 2023) M, Jayalakshmi; Joy, Francis; Nizam, Aatika; Krishna, Suresh Babu NaiduFused coumarins, because of their remarkable biological and therapeutic properties, particularly pyranocoumarins, have caught the interest of synthetic organic chemists, leading to the development of more efficient and environmentally friendly protocols for synthesizing pyranocoumarin derivatives. These compounds are the most promising heterocycles discovered in both natural and synthetic sources, with anti‐inflammatory, anti‐HIV, antitubercular, antihyperglycemic, and antibacterial properties. This review employed the leading scientific databases Scopus, Web of Science, Google Scholar, and PubMed up to the end of 2022, as well as the combining terms pyranocoumarins, synthesis, isolation, structural elucidation, and biological activity. Among the catalysts employed, acidic magnetic nanocatalysts, transition metal catalysts, and carbon‐based catalysts have all demonstrated improved reaction yields and facilitated reactions under milder conditions. Herein, the present review discusses the various multicomponent synthetic strategies for pyranocoumarins catalyzed by transition metal‐based catalysts, transition metal‐based nanocatalysts, transition metal‐free catalysts, carbon‐based nanocatalysts, and their potential pharmacological activities.Item Fungi-templated silver nanoparticle composite: synthesis, characterization, and its applications(MDPI AG, 2023-02-06) Joy, Francis; Devasia, Jyothis; Nizam, Aatika; Veerappa Lakshmaiah, Vasantha; Krishna, Suresh Babu Naidu; Krishna, Suresh Babu Naidu; Anthony William, ColemanThe self-assembly of nanoparticles on living bio-templates is a promising synthetic methodology adopted for synthesizing nano/microstructures with high efficiency. Therefore, the method of bio-templating offers various advantages in controlling the geometries of nano/microstructures, thereby increasing the efficiency of the synthesized material towards various functional applications. Herein, we utilized a filamentous fungus (Sclerotium rolfsii) as a soft bio-template to generate silver nanoparticle (AgNP) microtubules adhering to the fungal hyphae. The resulting composite combines the unique properties of silver nanoparticles with the biological activity of the fungi. The 3D fungal hyphae–silver nanoparticle (FH-AgNP) composite was characterized using SEM, elemental analysis, and the X-ray diffraction technique. Additionally, to highlight the functional application of the synthesized composite, dye degradation studies of methylene blue under visible light was effectuated, and a percentage degradation of 67.86% was obtained within 60 min, which highlights the potent catalytic activity of FH-AgNPs in dye degradation. Further, the antibacterial study of the composite was carried out against the bacterium Escherichia coli, and it was found that 200 µg of the composite exhibited maximum antibacterial properties against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacteria. Overall, fungi-templated silver nanoparticle composites are a promising area of research due to their combination of biological activity and unique physical and chemical properties.