Green Synthesis of Silver Nanoparticles Using Diospyros malabarica Fruit Extract and Assessments of Their Antimicrobial, Anticancer and Catalytic Reduction of 4-Nitrophenol (4-NP).

Kaushik Kumar Bharadwaj,Tanmay Sarkar,Sonit Kumar Gogoi,Siddhartha Pati,Hisham Atan Edinur,Nayanjyoti Kakati,Bhabesh Kumar Choudhury,Zulhisyam Abdul Kari,Debabrat Baishya,Bijuli Rabha

doi:10.3390/nano11081999

Abstract

The green synthesis of silver nanoparticles (AgNPs) has currently been gaining wide applications in the medical field of nanomedicine. Green synthesis is one of the most effective procedures for the production of AgNPs. The Diospyros malabarica tree grown throughout India has been reported to have antioxidant and various therapeutic applications. In the context of this, we have investigated the fruit of Diospyros malabarica for the potential of forming AgNPs and analyzed its antibacterial and anticancer activity. We have developed a rapid, single-step, cost-effective and eco-friendly method for the synthesis of AgNPs using Diospyros malabarica aqueous fruit extract at room temperature. The AgNPs began to form just after the reaction was initiated. The formation and characterization of AgNPs were confirmed by UV-Vis spectrophotometry, XRD, FTIR, DLS, Zeta potential, FESEM, EDX, TEM and photoluminescence (PL) methods. The average size of AgNPs, in accordance with TEM results, was found to be 17.4 nm. The antibacterial activity of the silver nanoparticles against pathogenic microorganism strains of Staphylococcus aureus and Escherichia coli was confirmed by the well diffusion method and was found to inhibit the growth of the bacteria with an average zone of inhibition size of (8.4 ± 0.3 mm and 12.1 ± 0.5 mm) and (6.1 ± 0.7 mm and 13.1 ± 0.5 mm) at 500 and 1000 µg/mL concentrations of AgNPs, respectively. The anticancer effect of the AgNPs was confirmed by MTT assay using the U87-MG (human primary glioblastoma) cell line. The IC50 value was found to be 58.63 ± 5.74 μg/mL. The results showed that green synthesized AgNPs exhibited significant antimicrobial and anticancer potency. In addition, nitrophenols, which are regarded as priority pollutants by the United States Environmental Protection Agency (USEPA), can also be catalytically reduced to less toxic aminophenols by utilizing synthesized AgNPs. As a model reaction, AgNPs are employed as a catalyst in the reduction of 4-nitrophenol to 4-aminophenol, which is an intermediate for numerous analgesics and antipyretic drugs. Thus, the study is expected to help immensely in the pharmaceutical industries in developing antimicrobial drugs and/or as an anticancer drug, as well as in the cosmetic and food industries.

Highlights

Nowadays, nanotechnology is a rapidly developing field and has a wide range of applications in biomedicine, drug delivery, bioimaging, bio-sensing devices, optoelectronics, catalysis and in environmental protection due to the exemplary properties, such as biocompatibility, high productivity, rapid production and cost-effectiveness [1,2,3,4,5].Among nanomaterials, metal nanoparticles, such as silver, copper, zinc, gold, titanium and magnesium, have been gaining immense magnitude for their applications and play a major role in this field [6,7,8,9]
This study focused on the green synthesis of AgNPs using Diospyros malabarica aqueous fruit extract as a reducing and stabilizing agent
The U87-MG cell lines were obtained from the National Centre for Cell Science (NCCS), Pune, India

Summary

Introduction

Nanotechnology is a rapidly developing field and has a wide range of applications in biomedicine, drug delivery, bioimaging, bio-sensing devices, optoelectronics, catalysis and in environmental protection due to the exemplary properties, such as biocompatibility, high productivity, rapid production and cost-effectiveness [1,2,3,4,5].Among nanomaterials, metal nanoparticles, such as silver, copper, zinc, gold, titanium and magnesium, have been gaining immense magnitude for their applications and play a major role in this field [6,7,8,9]. Nanotechnology is a rapidly developing field and has a wide range of applications in biomedicine, drug delivery, bioimaging, bio-sensing devices, optoelectronics, catalysis and in environmental protection due to the exemplary properties, such as biocompatibility, high productivity, rapid production and cost-effectiveness [1,2,3,4,5]. Several physical and chemical methods have been widely employed for the synthesis of AgNPs, such as sonochemical, microwave, γ-rays, hydrothermal, wet chemical, laser ablation and sol-gel, but these methods have some disadvantages, such as their use of high beam energy, hazardous toxic wastes, require high capital costs and production of large amounts of toxic byproducts that cause environmental contamination [11,12,13]. Green synthesis of AgNPs is rapidly increasing due to its enhanced stability, nontoxicity, inexpensive, eco-friendly, simple and rapid method of preparation approaches, which are substitutes to hazardous physical and chemical methods. Green synthesized AgNPs from plants are being successfully employed in various pharmaceutical and biomedical fields, such as antimicrobial, antibiofilm, antifungal, anticancer, anti-angiogenic therapy, anti-inflammatory, antioxidant, antiviral, drug delivery systems, gene therapy, bioimaging and wound healing [14,15,16,17,18,19,20,21,22,23]

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Results

Conclusion