In Vitro Antioxidant, Antitumor and Photocatalytic Activities of Silver Nanoparticles Synthesized Using Equisetum Species: A Green Approach.

Denisa Batir-Marin,Alexandra Iacobescu,Adrian Fifere,Monica Hancianu,Monica Boev,Liliana Verestiuc,Andreia Corciova,Oana Cioanca,Cornelia Mircea,Ana Flavia Burlec

doi:10.3390/molecules26237325

Abstract

The ethanolic extracts of three Equisetum species (E. pratense Ehrh., E. sylvaticum L. and E. telmateia Ehrh.) were used to reduce silver ions to silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV-Vis spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) measurements. FTIR data revealed the functional groups of biomolecules involved in AgNPs synthesis, such as O-H, C-H, C=O, C-O, and C-C. EDX spectroscopy was used to highlight the presence of silver, while DLS spectroscopy provided information on the mean diameter of AgNPs, that ranged from 74.4 to 314 nm. The negative Zeta potential values (−23.76 for Ep–AgNPs, −29.54 for Es–AgNPs and −20.72 for Et–AgNPs) indicate the stability of the obtained colloidal solution. The study also focused on establishing the photocatalytic activity of AgNPs, which is an important aspect in terms of removing organic dyes from the environment. The best photocatalytic activity was observed for AgNPs obtained from E. telmateia, which degraded malachite green in a proportion of 97.9%. The antioxidant action of the three AgNPs samples was highlighted comparatively through four tests, with the best overall antioxidant capacity being observed for AgNPs obtained using E. sylvaticum. Moreover, the biosynthesized AgNPs showed promising cytotoxic efficacy against cancerous cell line MG63, the AgNPs obtained from E. sylvaticum L. providing the best result, with a LD50 value around 1.5 mg/mL.

Highlights

The potential use of nanomaterials is a continuously developing research field
Biological methods currently represent the center of attention for researchers, since they provide numerous advantages, given that they involve eco-friendly processes, low costs and offer the possibility of avoiding high temperatures and pressure
The current trend in AgNPs synthesis is the use of microorganisms, enzymes, and plants extracts

Summary

Introduction

In particular, have received special attention due to their widespread applications in areas such as medicine, electronics, cosmetics and food, optics, chemical industry and many others [1,2]. For AgNPs synthesis, a variety of chemical, physical and biological methods can be used. Biological methods currently represent the center of attention for researchers, since they provide numerous advantages, given that they involve eco-friendly processes, low costs and offer the possibility of avoiding high temperatures and pressure. The current trend in AgNPs synthesis is the use of microorganisms, enzymes, and plants extracts. Plants are usually preferred given their high accessibility and the presence of biological compounds that can participate in this process, as well as the feasibility of the synthesis process [5,6]

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