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Zinc oxide nanoparticles (ZnO NPs) are becoming an innovative agent in biological and environmental applications due to its unique characteristics, biocompatibility, low cost and toxicity. In this study, the composite ZnO NPs using Rhododendron arboreum (R. arboreum) stem bark were synthesized and characterized for UV–visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The biomedical assessment of the synthesized nanoparticles showed zones of inhibition of 23 ± 0.09, 18 ± 0.1 and 16 ± 0.05 mm, against the Klebsiella pneumoniae (K. pneumoniae), Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains, respectively. Likewise, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against K. pneumoniae, S. aureus, and E. coli were found to be 34 ± 0.21 and 72.71 ± 0.47, 47 ± 0.11 and 94.86 ± 0.84 and 94 ± 0.18 and 185.43 ± 0.16 µg/mL, respectively. The biosynthesized ZnO NPs resulted in significant eradication of the outer and inner membranes of the tested bacterial cells. In addition, the environmental application of the synthesized ZnO NPs also showed time-dependent photocatalytic degradation activity and revealed 65% methyl orange dye degradation with an irradiation period of 6 h. The findings of this study suggest the suitability of the novel R. arboreum stem bark-based ZnO NPs as an effective ameliorant against bactericidal activities and photocatalytic potential for the removal of potentially toxic substances from water. [ABSTRACT FROM AUTHOR]

Three new thiourea-based thermo-reversible, low molecular weight organogelators (LMOGs) 3-5 have been synthesized using (+)-Dehydroabietylamine (DAA, a tricyclic diterpene) employing DLS (Diterpene-Linker-spacer) strategy. (+) DAA was converted into isothiocynates through a cascade of reactions and cross-coupled with primary amines to furnish thiourea 3-5 with respective spacers. The structures of gelators 3-5 were confirmed through 1H-NMR and 13C-NMR spectroscopy, high-resolution electron spray ionization mass spectrometry (HRESI–MS, positive mode) and FTIR spectroscopy. Gelation potential of gelators 3-5 was investigated through inverted test tube method and sol–gel transition measured by ball-dropping method. The results revealed that unbranched alkyl groups furnish gelation and their gelation ability increases with increasing spacer length. Gelator 5 with dodecyl chain found to be excellent gelator that can gelate hexane (spontaneously), toluene, methanol, ethanol, petrol, and diesel. Morphology of gels was studied though scanning electron microscopy exhibiting fibrillar to lamellar structure with a thickness in the range of 9.5 nm to 5.0 μm with increasing length of spacer. [ABSTRACT FROM AUTHOR]

Background: Lignin in sugarcane bagasse (SB) hinders its utilization by microorganism, therefore, pretreatment methods are employed to make fermentable components accessible to the microbes. Multivariate analysis of different chemical pretreatment methods can aid to select the most appropriate strategy to valorize a particular biomass. Results: Amongst methods tested, the pretreatment by using sodium hydroxide in combination with methyltrioctylammonium chloride, an ionic liquid, (NaOH+IL) was the most significant for xylanase production by Bacillus aestuarii UE25. Investigation of optimal levels of five significant variables by adopting Box-Behnken design (BBD) predicted 20 IU mL− 1 of xylanase and experimentally, a titer of 17.77 IU mL− 1 was obtained which indicated the validity of the model. The production kinetics showed that volumetric productivity of xylanase was much higher after 24 h (833.33 IU L− 1 h− 1) than after 48 h (567.08 IU L− 1 h− 1). The extracted xylan from SB induced more xylanase in the fermentation medium than pretreated SB or commercially purified xylan. Nuclear Magnetic Resonance, Fourier transform infrared spectroscopy and scanning electron microscopy of SB indicated removal of lignin and changes in the structure of SB after NaOH+IL pretreatment and fermentation. Conclusion: Combined pretreatment of SB with alkali and methyltrioctylammonium chloride appeared better than other chemical methods for bacterial xylanase production and for the extraction of xylan form SB. [ABSTRACT FROM AUTHOR]

In this study, an attempt was made to synthesize silver nanoparticles (Ag-NPs) using Grewia optiva leaf extract and isolated compounds. The bioreductant capacity of Grewia optiva leaf extract for the synthesis of Ag-NPs was assessed using various confirmatory techniques like thermogravimetric analysis (TGA), particle size analysis (PSA), energy-dispersive X-ray (EDX), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and UV-Visible spectroscopy. The presence of various bioactive compounds in leaf aqueous extract was confirmed through HPLC analysis, and 8 compounds were identified among the different peaks present in the chromatogram. Biopotencies like antioxidant, antibacterial, and effect on hair growth were determined for extract and NPs. Antioxidant capacities were assessed through standard ABTS and DPPH methods. The antibacterial potential was evaluated in terms of zone of inhibition, minimum bactericidal concentration, and minimum inhibitory concentration of the Ag-NPs and the leaf extract against selected strains of bacteria, whereas the effect on growth of rabbit hair was studied through topical treatment for a specific period of time. Better antibacterial and DPPH and ABTS free radical inhibition was observed for the formulated Ag-NPs as compared to leaf extract. The previously isolated eight compounds from this plant's chloroform and ethyl acetate extracts were also tested for their bioreductant capacities. Out of them, the highest amount of precipitates was obtained with compound VII ((2,5-dihydroxyphenyl)-3 ′ ,6 ′ ,8 ′ -trihydroxyl-4H-chromen-4 ′ -one). The study implies that the biogenically engineered nanoscale particles could have promising biological activities in comparison to parental extract and they need to be investigated further as potential therapeutic agents to be used as antibacterial and antioxidant agents and for hair growth enhancement. [ABSTRACT FROM AUTHOR]

Green synthesis of silver nanoparticles (AgNPs) employing an aqueous plant extract has emerged as a viable eco-friendly method. The aim of the study was to synthesize AgNPs by using plant extract of Sanvitalia procumbens (creeping zinnia) in which the phytochemicals present in plant extract act as a stabilizing and reducing agent. For the stability of the synthesized AgNPs, different parameters like AgNO3 concentration, volume ratios of AgNO3, temperature, pH, and contact time were studied. Further, AgNPs were characterized by UV–visible spectroscopy, FT-IR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), and EDX (Energy Dispersive X-ray Spectrometer) analysis. FT-IR analysis showed that the plant extract contained essential functional groups like O–H stretching of carboxylic acid, N–H stretching of secondary amides, and C–N stretching of aromatic amines, and C–O indicates the vibration of alcohol, ester, and carboxylic acid that facilitated in the green synthesis of AgNPs. The crystalline nature of synthesized AgNPs was confirmed by XRD, while the elemental composition of AgNPs was detected by energy dispersive X-ray analysis (EDX). SEM studies showed the mean particle diameter of silver nanoparticles. The synthesized AgNPs were used for photocatalytic degradation of Orange G and Direct blue-15 (OG and DB-15), which were analyzed by UV-visible spectroscopy. Maximum degradation percentage of OG and DB-15 azo dyes was observed, without any significant silver leaching, thereby signifying notable photocatalytic properties of AgNPs. [ABSTRACT FROM AUTHOR]

The need of non-toxic synthesis protocols for nanoparticles arises developing interest in biogenic approaches. The present project was focused on cost effective, environment congenial synthesis of Ag nanoparticles and their biological applications. Leaf and root extracts of Ricinus communis were used as a reducing and stabilizing agent in synthesis process. A Proposed mechanism in published literature suggested that Indole-3-acetic acid, l-valine, triethyl citrate, and quercetin-3-0-p-d-glucopyranoside phytoconstituents of Ricinus communis act as reducing and capping agents. The synthesized Ag NPs were characterized with a help X-ray diffractometer, Transmission electron microscopy, UV-Vis spectrophotometry and Fourier Transform Infrared Spectroscopy (FTIR). The XRD results inveterate the synthesis of pure nano size crystalline silver particles. The FTIR data revealed the possible functional groups of biomolecules involved in bio reduction and capping for efficient stabilization of silver nanoparticles. TEM analysis confirmed the almost spherical morphology of synthesized particles with mean size 29 and 38 nm for R-Ag-NPs (root) and L-Ag-NPs (leaf), respectively. The stability of synthesized nanoparticles was examined against heat and pH. It was observed that synthesized nanoparticles were stable up to 100 °C temperature and also showed stability in neutral, basic and slightly acidic medium (pH 05–06) for several months while below pH 5 were unstable. The synthesized silver nanoparticles had promising inhibition efficiency in multiple applications, including as bactericidal/fungicidal agents and Urease/Xanthine oxidase enzymes inhibitors. The cytotoxicity of synthesized nanoparticles shows that the concentration under 20 μg/mL were biologically compatible. [ABSTRACT FROM AUTHOR]