Clove-mediated green synthesis of silver nanoparticles and in vitro investigation of their antimicrobial, antioxidant, and anticancer potential.

内容摘要

Green synthesis of silver nanoparticles (AgNPs) using plant extracts offers an eco-friendly and sustainable strategy for developing multifunctional nanomaterials with biomedical applications. This study aimed to biosynthesize AgNPs using Syzygium aromaticum (clove) extract and evaluate their physicochemical characteristics and antioxidant, anti-inflammatory, antiviral, anticancer, and antibacterial activities. AgNPs were biosynthesized using clove extract and characterized by Ultraviolet-Visible Spectroscopy (UV-Vis), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Energy-Dispersive X-ray Spectroscopy (EDX). Antioxidant activity was determined by IC&#x2085;&#x2080; analysis, while anti-inflammatory potential was assessed using hemolysis protection and human red blood cell (HRBC) membrane stabilization assays. Antiviral activity was evaluated against hepatitis A virus (HAV), Coxsackievirus B4 (COXB4), and herpes simplex virus type 1 (HSV-1). Cytotoxicity was assessed in human colorectal carcinoma (CaCO&#x2082;) and normal lung fibroblast (Wi-38) cells. Antibacterial activity was tested against multidrug-resistant (MDR) bacterial strains, and quantitative molecular analyses were performed to determine the expression of bacterial virulence genes and cancer-related genes. All reported values represent the mean of three independent experiments. The synthesized AgNPs were predominantly spherical, well dispersed, and had an average particle size of approximately 9.5 nm. XRD confirmed a crystalline face-centered cubic (fcc) structure, while UV-Vis analysis showed a characteristic surface plasmon resonance peak at 437 nm, confirming successful nanoparticle formation. The AgNPs exhibited strong antioxidant activity with an IC&#x2085;&#x2080; of approximately 13.5 &#x3bc;g/mL and demonstrated significant anti-inflammatory activity through membrane stabilization and hemolysis protection. Antiviral assays showed marked inhibition of HAV, COXB4, and HSV-1 at 250 &#x3bc;g/mL, with the highest inhibition observed against HAV (74%). Cytotoxicity studies revealed selective anticancer activity, with an IC&#x2085;&#x2080; of approximately 137 &#x3bc;g/mL against CaCO&#x2082; cells compared with 387 &#x3bc;g/mL for Wi-38 cells. Broad-spectrum antibacterial activity was observed against MDR Staphylococcus aureus (ATCC 27217), Staphylococcus haemolyticus (ATCC 29970), Escherichia coli (BAA-197), and Klebsiella pneumoniae (BAA-1705). Molecular analyses demonstrated significant suppression of bacterial virulence genes, including luxS in E. coli (70%), fnbA-a and cna in S. aureus (74%), fnbA-h in S. haemolyticus (77%), and rmpA in K. pneumoniae (81%) at AgNP concentrations of 10 &#x3bc;g/mL for Gram-positive and 12.5 &#x3bc;g/mL for Gram-negative strains. In CaCO&#x2082; cells, AgNP treatment significantly downregulated c-MYC (0.49-fold), K-RAS (0.67-fold), and BCL2 (0.78-fold; p < 0.01), while significantly upregulating BAX (1.74-fold). Clove-mediated AgNPs demonstrated potent multifunctional biological activities, including antioxidant, anti-inflammatory, antiviral, selective anticancer, and antibacterial effects, accompanied by modulation of cancer-associated and bacterial virulence genes. These findings highlight the therapeutic potential of biosynthesized AgNPs as promising candidates for the development of novel antimicrobial and anticancer nanomedicines.