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Abstract The present study is focused on the synthesis of silver nano particles (Ag NPs) using an aqueous extract of the whole plant of Sida cordifolia as a potential bio-reducing agent and assessment of their antibacterial activity. UV–Vis spectroscopy of composed silver colloidal solution displayed surface Plasmon resonance peak at 420 nm. XRD and TEM analysis revealed the morphology as ultra-small, monodispersed spherical nanoparticles with face-centered cubic structure and mean particle size of 3–6 nm. This ultra-small nano size might owe to the slow reaction time and phytochemicals existing in the S. cordifolia extract. The Ag NPs are trailed for antibacterial activity against 5 fish (Aeromonas hydrophila , Pseudomonas fluorescence , Flavobacterium branchiophilum, Edwardsiella tarda and Yersinia rukeri) and 4 human (Escherichia coli , Klebsiella pneumonia , Bacillus subtilis and Staphyloccocus aureus) bacterial pathogens. In all the cases, Ag NPs from Sida cordifolia plant extract manifested noteworthy antibacterial effects on par with positive control i.e.; Gentamicin. Highlights • First report on the biosynthesis of Ag NPs using Sida Cordifolia plant extract. • Ultra Small, Monodispersed Ag NPs using green Synthesis. • Act as a good antibacterial agent against various human and fish bacterial pathogens. • Ag NPs were characterized with UV–Vis, XRD, SEM and TEM. [ABSTRACT FROM AUTHOR]

In the present study, green synthesis of silver nanoparticles (AgNPs) is demonstrated using medicinal herb Swertia paniculata extract. The plant extract acted both as reducing and capping agents during synthesis process, where silver nitrate was used as silver source. Subsequent analysis revealed that particles had size range between 31 and 44 nm and were spherical in shape. Among reaction parameters, temperature and time had significantly influenced the synthesis reaction. Also, synthesized nanoparticles were found stable up to 90 days. Further, antimicrobial activity against gram negative and gram positive bacterial strains was done and results showed that synthesized AgNPs had better antimicrobial activity against Pseudomonas aeruginosa , Klebsiella pneumoniae under standard incubation conditions. Study shows that these particles can be very promising in biomedical applications in future. [ABSTRACT FROM AUTHOR]

In this study, a natural extract from the plant Radix hedysari (ER) was proven to be useful for the green synthesis of silver nanoparticles (AgNPs) and ER-AgNPs in particular. Considering the complexity of plant extracts, high-pressure liquid chromatography (HPLC) was effective at confirming the components of ER, surprisingly, formononetin was found to comprise more than 85% of the total contents. Since formononetin was confirmed to be the primary component of ER, this compound was also used as the basis to synthesize AgNPs designated FMT-AgNPs that was highly pure and of high quality. The FMT-AgNPs functionalized by formononetin were optimized for further study. A simple, fast and sensitive colorimetric method detect formothion was achieved using FMT-AgNPs. A wide linear range from 0.1 μM to 10 μM was established with a low limit of detection (LOD) of 14.6 nM. Since formononetin performed multiple roles during the synthesis, it was confirmed that the mechanism of detection was based on aldol condensation, intermolecular hydrogen bonds and electrostatic attraction between formononetin and formothion. Finally, the green synthesized FMT-AgNPs were further applied in typical fruit and vegetable samples, indicating that FMT-AgNPs were potentially highly useful. [Display omitted] • The plant extract (ER) and formononetin was utilized to green synthesize silver nanoparticles (ER-AgNPs/FMT-AgNPs). • FMT-AgNPs were proven to be pure and of high quality. • The relevant synthesis or mechanism of detection was clearly explained. • FMT-AgNPs were sensitive and selective for the detection of formothion. • FMT-AgNPs were applied to detect formothion in typical vegetable and fruit samples. [ABSTRACT FROM AUTHOR]

Hypothesis Biological synthesis of silver nanoparticles is a cost effective natural process where the phytochemicals specifically phenols, flavonoids and terpenoids present in the plant extracts act as capping and reducing agent. Due to their nano size regime the silver nanoparticles may directly bind to the DNA of the pathogenic bacterial strains leading to higher antimicrobial activity. Experiment In the current study silver nanoparticles were synthesised using plant extracts from different origin Cucurbita maxima (petals), Moringa oleifera (leaves) and Acorus calamus (rhizome). The synthesised nanoparticles were characterized by UV–visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), field emission scanning electron microscopy (Fe-SEM) and Fourier transform infrared spectroscopy (FTIR). Finding Highly crystalline, roughly spherical and cuboidal silver nanoparticles of 30–70 nm in size were synthesised. The nanoparticles provided strong antimicrobial activity against pathogenic strains. The effect of the synthesised nanoparticles against A431 skin cancer cell line was tested for their toxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye. The IC 50 values of 82.39 ± 3.1, 83.57 ± 3.9 and 78.58 ± 2.7 μg/ml were calculated for silver nanoparticles synthesised by C. maxima , M. oleifera and A. calamus respectively. [ABSTRACT FROM AUTHOR]