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Faculty of Applied Sciences

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Subject: search.filters.subject.Antibacterial activity

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    Green synthesis of silver nanoparticles using flower extracts of Aerva lanata and their biomedical applications
    (Informa UK Limited, 2022-01-02) Palithya, Sashikiran; Gaddam, Susmila Aparna; Kotakadi, Venkata Subbaiah; Penchalaneni, Josthna; Golla, Narasimha; Krishna, Suresh Babu Naidu; Naidu, C.V.
    In the present study, green synthesis of silver nanoparticles (AgNPs) was performed using flower extracts of Aerva lanata (Al) from Amaranthaceae family. The size, shape, and elemental composition of the silver nanoparticles (AgNPs) was studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and UV-visible spectroscopy. The dynamic light scattering (DLS), of silver nanoparticles (AgNPs) exhibited mean size of 7.6 nm in the range of 5–15 nm, having a poly-dispersed indexed value of 0.419. Zeta potential contributing to the stability of silver nanoparticles was recorded as −18.7 mV. Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis confirmed the presence of the synthesized AgNPs with an average size range 7 ± 3 nm. The biosynthesized silver nanoparticles displayed antibacterial activity against Gram-positive and Gram-negative bacteria. The 2,2’-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay revealed antioxidant potential of silver nanoparticles in the concentration of 100 µg/ml. The photocatalytic activity of silver nanoparticles was evaluated using decolourization of the dyes under the sunlight using UV-Vis. spectroscopy. The results suggest that biosynthesized silver nanoparticles from A. lanata (Al-AgNPs) flower extracts have broad spectrum antibacterial, antioxidant and catalytic activities may be useful in a variety of biomedical and industrial applications.
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    Biosynthesis of ZnO nanoparticles using Jacaranda mimosifolia flowers extract: Synergistic antibacterial activity and molecular simulated facet specific adsorption studies
    (Elsevier, 2016) Sharma, Deepali; Sabela, Myalowenkosi Innocent; Kanchi, Suvardhan; Mdluli, Phumlani Selby; Singh, Gulshan; Stenström, Thor-Axel; Bisetty, Krishna
    The naturally occurring biomolecules present in the plant extracts have been identified to play an active role in the single step formation of nanoparticles with varied morphologies and sizes which is greener and environmen-tally benign. In the present work, spherical zinc oxide nanoparticles (ZnO NPs) of 2–4 nm size were synthesized using aqueous extract of fallen Jacaranda mimosifolia flowers (JMFs), treated as waste. The microwave assisted synthesis was completed successfully within 5 min. Thereafter, phase identification, morphology and optical band gap of the synthesized ZnO NPs were done using X-ray diffraction (XRD), high resolution transmission elec-tron microscopy (HRTEM) and UV–Visible spectroscopy techniques. The composition of JMFs extract was ana-lyzed by gas chromatography–mass spectrometry (GC–MS) and the ZnO NPs confirmation was further explored with fourier transform infrared spectroscopy (FTIR). The GC–MS results confirmed the presence of oleic acid which has high propensity of acting as a reducing and capping agent. The UV–Visible data suggested an optical band gap of 4.03 eV for ZnO NPs indicating their small size due to quantum confinement. Further, facet specific adsorption of oleic acid on the surface of ZnO NPs was studied computationally to find out the im-pact of biomolecules in defining the shape and size of NPs. The viability of gram negative Escherichia coli and gram positive Enterococcus faecium bacteria was found to be 48% and 43%, respectively at high concentration of NPs.