In Vitro Human Microbiota Response to Exposure to Silver Nanoparticles Biosynthesized with Mushroom Extract.

Emanuel Vamanu,Mihaela Ene,Bogdan Biță,Ionela Sârbu,Cristina Ionescu,Liviu Crăciun

doi:10.3390/nu10050607

Abstract

The ability to orally administer silver nanoparticles (AgNPs) in enteric capsules implies a direct interaction with the colon microbiota. The in vitro effect provides a portrayal of the functional properties under in vivo conditions. The purpose of this study was to describe a green AgNP synthesis process, using aqueous extract from Lactarius piperatus mushroom, and to characterize the nanomaterial. We determined its antimicrobial and antioxidant effects in vitro in the microbiota of healthy individuals via the GIS1 system—a colon transit simulator. Per the quantitative polymerase chain reaction (qPCR) results, the antimicrobial properties of the AgNPs affected the initial share of different enteric species by decreasing the Bacteroides, Enterobacteriaceae, and Lactobacillus populations and favoring the Bifidobacterium group. The association between AgNPs and wild mushroom L. piperatus extract had a synergistic antibacterial activity against various pathogenic microorganisms while the mushroom extract reduced biofilm formation. Administration of AgNP maintained its constant antioxidant status, and it was correlated with a reduction in ammonium compounds. The physicochemical characterization of these NPs complemented their biochemical characterization. The maximum ultraviolet-visible spectroscopy (UV-VIS) absorbance was observed at 440 nm, while the Fourier transform infrared (FT-IR) spectrum reached a peak at 3296 cm–1, which was correlated with the high-performance liquid chromatographic analysis (HPLC). The major phenolic compound was homogentisic acid. The size (49 ± 16 nm in diameter) and spherical shape of the NPs were correlated with their biological effects in vitro.

Highlights

Noble metal-based nanoparticles (NPs) are widely used in biopharmaceutical applications [1] to develop innovative pharmaceutical forms
The bond responsible for NP synthesis due to Ag reduction was identified at 1147.76 cm−1 which correspond with the Fourier transform infrared (FTIR) spectra of the compound [21]
AgNPs were synthesized beginning with an aqueous extract of the L. deliciosus mushroom and it was characterized by ultraviolet-visible spectroscopy (UV-VIS) spectroscopy, FTIR, Scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. quantitative polymerase chain reaction (qPCR)

Summary

Introduction

Noble metal-based nanoparticles (NPs) are widely used in biopharmaceutical applications [1] to develop innovative pharmaceutical forms. Silver NP (AgNP) synthesis, in particular, which uses plant extract as a reducing agent, is more advantageous over any other methods that use microorganisms; this process has received great attention in recent years [2]. The novel structure can start from different extracts (aqueous or alcoholic), using the reducing potential of different medicinal plants [3], medicinal mushrooms [4], or bacteria [5]. A recent study showed that aqueous extract from Pleurotus (P.) ostreatus can act as an efficient reducing agent for the large-scale production of novel antimicrobial compounds [6]. Bioactive compounds in edible mushrooms have high biological value [8], and this may add or bring potentiating effects to the antimicrobial properties of silver. It is very useful to have the structural details of the compound’s nanostructure, its expected shape, and its direct influence on the biological response

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