Silver nanoparticles (Ag NPs) are now widely used as antibacterial and antifungal materials in different consumer products. We report here the preparation of Ag NPs by neem leaves extract (Azadirachta) reduction and trisodium citrate-sodium borohydride reduction methods, and study of their phytotoxicity. The nanoparticles were characterized by UV-Vis spectroscopy, FTIR, and atomic force microscopy (AFM) techniques. Both neem-coated and citrate-coated Ag NPs exhibit surface plasmon around 400 nm, and their average sizes measured by AFM are about 100 and 20 nm, respectively. Antibacterial and antifungal activities of these nanomaterials have been studied by simple pea seed germination and disk diffusion methods. It has been observed from the growth of root and shoot, citrate-coated Ag NPs significantly affect seedling growth, but neem-coated Ag NPs exhibit somehow mild toxicity toward germination process due to the nutrient supplements from neem. On the other hand, antifungal activity of neem-coated Ag NPs has been found much higher than that of citrate-coated Ag NPs due to the combined effects of antifungal activity of neem and Ag NPs. Present research primarily indicates a possible application of neem-coated Ag NPs as a potential fungicide.
Citrus macroptera (CM) fruit juice was used to reduce gold ions (Au3+) and to stabilize as‐formed gold nanoparticles (AuNPs). CM‐AuNPs exhibit surface Plasmon resonance (SPR) peak at 544 nm. Transmission Electron Microscope (TEM) study reveals that they are multi‐shaped, predominantly pseudo‐spherical with a diameter 20 nm. They have surface charge −30 mV and possess FCC lattice pattern. Particles could effectively inhibit the biofilm formation of Pseudomonas aeruginosa bacteria. Experimental study shows that CM‐AuNPs make the bacteria cripple to generate EPS and pyocyanin. AFM images of the structure of biofilm reveal that CM‐AuNPs indeed efficiently disrupt the biofilm structure. CM‐AuNPs in combination with Sub‐MIC dose of gentamicin against P. aeruginosa bacteria exhibit quite high efficiency. The cytotoxic effect of CM‐AuNPs against three human cancer cell line show that they are comparatively more efficient to regulate the growth of HepG2 (liver cancer cell line) than that of A 549 (adenocarcinogenic human alveolar basal epithial cell) and MDA‐MB 468 (breast cancer cell). Thus, the CM‐AuNPs could be treated as a potential anti‐biofilm and anti‐cancer agent.
The study of inter‐conversion between molecules, especially biologically and pharmaceutically important molecules, is extremely important. This study reports the inter‐conversion between two azo‐derivtives: azo‐6‐aminouracils to azo‐barbituric acids. We successfully converted the 1,3‐dimethyl‐5‐(arylazo)‐6‐aminouracils (Uazo‐1 to Uazo‐4) to 1,3‐dimethyl‐5‐(arylazo)‐barbituric acids (BAazo‐1 to BAazo‐4) (where aryl⇒C6H5‐(1); p‐MeC6H4‐(2), p‐ClC6H4‐(3), and p‐NO2C6H4‐(4)) following an acid‐hydrolysis path. The products were characterized using spectroscopic tools like UV‐vis, IR, and NMR spectroscopy. UV‐vis spectra of the as‐prepared dyes reveal that in contrast to the azo‐6‐aminouracils they are hardly responsive towards solvatochromism. IR spectra exhibit three characteristic >CO frequencies for as‐prepared azobarbituric acids instead of two for mother azo‐6‐aminouracils. 1H NMR spectra which reflect the existence of solution species evidence the absence of >CNH group (characteristic imido‐H at the 6‐position of hydrazone species of azo‐6‐aminouracils) and consequence presence of >CO group at the same position in as‐prepared azobarbituric acids. They exhibit structural emissions in the range of 400–440 nm upon excitation at 360 nm. The determined acid dissociation constant (pKa) values of BAazos increase according to the following sequence: BAazo‐2>1>3>4.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.