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Background Bimetallic nanoparticles (BNPs) are used in attractive applications in the medicinal, green catalyst, optics, electrochemical and so on. Apart from the catalytic activity, the chemical synthesized BNPs is less energy and environmentally highly toxic. Hence, Au-Ag BNPs prepared by the green synthesis method is suggested to be eco-friendly and have a potential catalytic reduction/degradation activity against environmentally polluted organic dyes. Materials and method In this present work, Ultrasound-Assisted green synthesis of Gold-Silver Bimetallic Nanoparticles (Au-Ag BNPs) was synthesized from Lawsonia inermis seed extract aqueous fraction. The effects of the extract volume, metal ions concentration, pH, and temperature were investigated to determine the optimum conditions of the synthesis of Au-Ag BNPs. Results and discussion UV-vis absorbance of the surface Plasmon resonance centre at 537 nm was confirmed the product of Au-Ag BNPs. FT-IR spectroscopy to determine the phytochemicals groups of the plant extract and Au-Ag BNPs. High-resolution transmission electron microscopy image of Au-Ag BNPs shows polygonal, spherical and irregular shaped with particle sizes 15-35 nm. Under UV-vis the light source, the obtained BNPs had a strong photocatalytic reduction/degradation activity against 4-nitrophenol and methyl orange dye in the presence of NaBH4.

A simple phyto-assisted synthesis of zinc oxide nanowires (ZnO NWs) employing urinary tract infection (UTI) controlling traditional medicinal plant Pedalium murex L. mucilage, their silver (Ag) doping by co-precipitation method has been reported. The synthesized Ag-doped ZnO NWs photocatalytic action on the UTI antibiotic nitrofurantoin (NFT) and the dye methylene blue (MB) has been reported. The synthesized NPs optical, biocomponents, structural and chemical properties were determined by UV-vis spectroscopy, FTIR, XRD, SEM, TEM, EDAX, particle size analyzer. Photocatalytic activity of the phyto-assisted synthetic Ag-doped ZnO NWs was investigated on the degradation of the antibiotic NFT and the dye MB. The percentage of degradation, as well as dye removal efficiency was calculated. The UV-vis absorption spectrum showed a surface plasmon resonance (SPR) band at 370 nm - 400 nm with blue and redshift. The vast bandgap energy (3.37 eV - 2.75 eV) reduction indicated the inclination of noble metal Ag on the surface of ZnO NWs. XRD diffractogram revealed the crystalline hexagonal wurtzite structure and c-axis oriented growth of the synthesized ZnO nanowires. FTIR spectra functional groups exposed the possible contribution of plant phytochemicals in the formation of nanowires. TEM micrographs showed the agglomerations of zinc cite crystal structure nanowire with silver inclination on their surface. EDX and SAED confirmed the elemental composition and purity of the synthesized Ag/ZnO nanowires. The synthesized Ag-doped ZnO nanowires achieved photocatalytic degradation of about 78.51% of the antibiotic NFT and 92.43% of MB dye in 150 min under UV irradiation. The present study establishes the likelihood of photocatalytic degenerative potency of the antibiotic nitrofurantoin and methylene blue employing photosynthesized phytosynthesized zinc oxide nanowires.

Cassia auriculata L., the flower aqueous extract was fractionated by separating funnel using n-hexane (A1), chloroform (A2), ethyl acetate (A3) and triple distilled water (A4). The A4 fraction was concentrated and determined the presence of preliminary phytochemicals such as tannins, flavonoids, glycosides, carbohydrates and polyphenolic compounds. These phytochemical compounds acted as reducing as well as a stabilizing agent in the green synthesis of Ag NPs from aqueous silver ions. Initially, the colour change and UV-vis absorbance surface Plasmon resonance strong, wide band located at 435nm has confirmed the synthesis of Ag NPs. The X-ray diffraction (XRD) pattern of Ag NPs shows a face-centered cubic crystal structure. The observed values were calculated by Debye-Scherrer equation to theoretical confirms the particle size of 18nm. The surface morphology of Ag NPs was viewed by HRTEM, the particles are spherical and triangle shapes with sizes from 10 to 35nm. Further, the Ag NPs was effective catalytic activity in the reduction of highly environmental polluted organic compounds of 4-nitrophenol and methyl orange. The green synthesis of Ag NPs seems to eco-friendly, cost-effective, conventional one spot synthesis and greater performance of catalytic degradation of environmentally polluted organic dyes.

The aim of the present investigation was to isolate and identify the phytochemicals from Semecarpus anacardium seeds and evaluate their activity against Gram positive and Gram negative bacterial strains (Bacillus subtilis MTCC 441, Staphylococcus aureus MTCC 96, Escherichia coli MTCC 1689 and Proteus vulgaris MTCC 742 using well diffusion method). The phytochemicals were isolated using silica gel column chromatography and characterized as catechol derivatives by spectroscopic analyses. The antimicrobial activity of the isolated catechol derivatives I-IV varied according to the dose and bacterial strains tested. Among the four catechol derivatives, catechol derivatives I and IV showed prominent antibacterial activity against both the positive and negative human pathogenic organisms compared to catechol derivatives II, III and tetracycline – a reference antibiotic drug. From these findings, it can be concluded that catechol derivatives I and IV possessed methyl group (CH3) in aromatic ring and no double bond in the aliphatic side chain which was not present in catechol derivatives II and III and they possessed double bonds in the aliphatic side chain and no methyl group in the aromatic ring. These may be the possible reason for showing more inhibitory activity of catechol derivatives I and IV. These results showed the effectiveness of catechol derivatives against tested bacterial strains. Further work is necessary to explore these antimicrobial compounds, which are useful in clinical applications.