Green synthesis and characterization of silver nanoparticles using belladonna mother tincture and its efficacy as a potential antibacterial and anti-inflammatory agent

Highlights

• Belladonna mother tincture for green synthesis of silver nanoparticles.

• The synthesized silver nanoparticles are highly stable with negative zeta potential.

• Various characterizations of biosynthesized silver nanoparticles are summarized.

• Different Biological properties of biosynthesized silver nanoparticles are evaluated.

Abstract

Biosynthesized silver nanoparticles is a promising area of interest for researchers of nano biosciences due to its wide range of applications and possibilities in biomedical sciences. Despite, the use of various biological compounds in green synthesis of silver nanoparticles, still there is a huge scope of further improvement for synthesizing stable and broadly applicable silver nanoparticles. Majorly biosynthesized silver nanoparticles have assessed as an antibacterial agent ignoring their other biological applications. So this present study aims to point the application of biosynthesized silver nanoparticles as an anti-inflammatory agent and probably is the first report where capability of Belladonna mother tincture to reduce AgNO₃ to Ag-Nanoparticles has been evaluated. The nanoparticles were characterized by UV–Vis spectroscopy, DLS, XRD and zeta potential measurements, and morphology was analysed by SEM and TEM. Anti-bacterial, anti-inflammatory and cytotoxicity effect of the synthesized nanoparticles was also evaluated. Thus, this possibly will be a novel environment-friendly technique to biosynthesize silver nanoparticles by a cost-effective and non-toxic manner.

Introduction

Numerous scientists have put distinct emphasis on the theme of nanotechnology with the solitary mission of enlightening the living standards of human being. Nanotechnology is the subdivision of technology that deals with proportions and tolerances of particles less than 100 nm, briefly it is a discipline of engineering, and technology that deals with the materials, whose any one of the dimension is within nanoscale (about 1–100 nm). Since the discovery of science and technology, synthesis of metal nanoparticles and nanocomposites is an emerging area of research and exploration in the field of material science for their unique size and shape;, and have reliant features that are different from the regular bulk structures [1,2]. Since the development of nanomaterials, metal nanoparticles has been extensively used in wide range of applications including sensing [3,4], catalysis [5,6], energy [7], drug & gene delivery [[8], [9], [10]] and electronics [11].

For the last few decades, silver nanoparticles (AgNPs) have been extensively used for their distinctive features and extensive range of applications. In the last few years silver nanoparticles (AgNPs) have emerged as one of the promising nanomaterial due to its unique properties, such as Surface Enhanced Raman Scattering (SERS), superior electrical and thermal conductivity, and most importantly due to their different promising bioactivities [[12], [13], [14], [15], [16]]. These different bioactivities include antifungal [17], anti-oxidant [18], antibacterial [19], anti-inflammatory [20], anticancer effects and non-viral carrier in gene therapy [9]. Among different applications, antibacterial activities of AgNPs have owned much consideration because they provide a solution to the problem of antibiotic resistance bacteria [21]. There are wide variety of approaches to produce AgNPs comprising physical and chemical methods [22]. Even if the chemical ways are effective but these approaches may suffer from toxicity owing to the chemicals used and the trouble in eradicating them. Additionally, chemical reagents used in these techniques are harmful to the environment [23]. To overcome these problems nowadays scientists are focusing on facile green synthesis routes for preparation of metal nanoparticles [24]. These types of synthesis method offer an economic, facile and eco-friendly way for preparation of engineered metal nanoparticles.

There are many reports on the synthesis of metal nanoparticles using microbes and plant materials [[25], [26], [27]]. Numerous investigations focused on the synthesis of silver nanoparticles using different plant extracts such as Sesbania grandiflora [28], Rubus glaucus [29], Benth Alpinia calcarate [15], and Artocarpus heterophyllus [30] and some of these also reported for their potential anticancer and antibacterial activities. Possibly, till now no one have tried to evaluate homeopathic mother tinctures of plant source for synthesizing nanoparticles and also synthesized nanoparticles using homeopathic mother tinctures of plant source, has not been evaluated for some precise biological activities in vitro as per reports. In homeopathy, majorly two forms of drugs are used, specifically, mother tinctures and potentized forms. Mother tinctures drugs are derived from plants, animals or minerals. For plants, it may be acquired as an ethanolic extract of the whole plant or some particular parts like root, leaves, bark, flowers, etc [31]. The mother tincture of the homeopathic drug BELLADONNA is the ethanolic extract of roots of the Atropa belladonnamade in a very concise method.

In this study, we report a one-step facile green method to prepare silver nanoparticles. Reduction of Ag⁺ions to Ag⁰ nanoparticles was done using belladonna mother tincture in which no extra reducing agent was used. Here belladonna mother tincture acted both as a reducing and stabilizing agent. The stability of nanoparticles plays a vibrant role during the synthesis of nanoparticles and most of the cases it become difficult to get stable nanoparticle [26]. But when examined this bio-synthesized nanoparticles was quite stable for around six weeks. The resulting AgNPs can be obtained in large quantities and in very cost effective method. The sizes of AgNPs were found to be in a range of 55–125 nm. The AgNPs produced exhibited good antibacterial effect as well as excellent anti-inflammatory effect. This hybrid nanomaterial provides an alternative material for antibacterial and anti-inflammatory drug.

On extensive literature search it was observed that not much work has so far been carried out on evaluating nano-precipitating property of any mother tincture including the one, obtained from the plant Atropa belladonna for preparation of Ag-nanoparticle and also not much reports on the evaluation of biological activities of the AgNPs produced using mother tincture including mother tincture obtained from the plant Atropa belladonna.