Preparation and physicochemical characterization of Ag nanoparticles biosynthesized by Lippia citriodora (Lemon Verbena).
The purpose of this study was to develop a simple biological method for the synthesis of Ag nanoparticles (AgNPs) using Lippia citriodora leaves aqueous extract as reducing agent. Transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD), and visible absorption spectroscopy (UV-vis) confirmed the reduction of silver ions to AgNPs. Stable, spherical crystalline AgNPs with well defined dimensions (average size of 15-30 nm) were obtained, on treating aqueous silver nitrate with the plant leaf aqueous extract. The kinetic of particles formation was proportional to the effect of reducing agent concentration and was enhanced by the increase of temperature from 25 degrees C to 95 degrees C. Time, temperature and extract concentration did not influence significantly the shape and size of nanoparticles. In order to identify the compounds responsible for the bioreduction of silver ions and stabilization of the AgNPs formed, we investigated the constituents of L. citriodora aqueous extract by high performance liquid chromatography (HPLC) and mass spectrometry (MS). The main compounds found were verbascoside, isoverbascoside, chrysoeriol-7-O-diglucoronide and luteonin-7-O-diglucoronide. The data obtained suggests that the isoverbascoside compound is responsible for Ag(+) ions reduction and act as capping agents of the nanoparticles afterwards.
Cruz
Diana
D
Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Centro de Química e Bioquímica, 1749-016 Lisboa, Portugal.
Falé
Pedro L
PL
Mourato
Ana
A
Vaz
Pedro D
PD
Serralheiro
M Luisa
ML
Lino
Ana Rosa L
AR
D055598:Chemical Phenomena; D002851:Chromatography, High Pressure Liquid; D047309:Flavones / Q000737:chemistry; D005960:Glucosides / Q000737:chemistry; D020719:Glucuronides / Q000737:chemistry; D007700:Kinetics; D032411:Lippia / Q000737:chemistry*; D013058:Mass Spectrometry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010316:Particle Size; D010636:Phenols / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D019163:Reducing Agents / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013696:Temperature; D014961:X-Ray Diffraction; D059808:Polyphenols
D047309:Flavones; D005960:Glucosides; D020719:Glucuronides; D010636:Phenols; D010936:Plant Extracts; D019163:Reducing Agents; D012834:Silver; C058956:acteoside; D059808:Polyphenols; C064683:isoacteoside