Cytotoxic and Apoptotic Effects of Green Synthesized Silver Nanoparticles via Reactive Oxygen Species-Mediated Mitochondrial Pathway in Human Breast Cancer Cells

Due to their exceptional physicochemical features, green synthesized silver nanoparticles (AgNPs) have been of considerable interest in cancer treatment. In the present study, for the first time, we aimed to green synthesize AgNPs from Euphorbia retusa and explore their anticancer potential on human breast cancer (MCF-7) cells. First, the green synthesized AgNPs (EU-AgNPs) were well characterized by UV-visible spectroscopy, Fourier transmission infrared (FTIR) spectrum, XRD, scanning and transmission electron microscopy (SEM and TEM), and EDX techniques. The characterization data exhibited that EU-AgNPs were spherical in shape and crystalline in nature with an average size of 17.8 nm. FTIR results established the presence of active metabolites in EU-AgNPs. Second, the anticancer effect of EU-AgNPs was evaluated against MCF-7 cells by MTT and neutral red uptake (NRU) assays. Moreover, morphological changes, ROS production, MMP, and apoptotic marker genes were also studied upon exposure to cytotoxic doses of EU-AgNPs. Our results showed that EU-AgNPs induce cytotoxicity in a concentration-dependent manner, with an IC50 value of 40 μg/mL. Morphological changes in MCF-7 cells exposed to EU-AgNPs also confirm their cytotoxic effects. Increased ROS and decreased MMP levels revealed that EU-AgNPs induced oxidative stress and mitochondrial membrane dysfunction. Moreover, ROS-mediated apoptosis was confirmed by elevated levels of proapoptotic marker genes (p53, Bax, caspase-3, and caspase-9) and reduced levels of an antiapoptotic gene (Bcl-2). Altogether, these findings suggested that EU-AgNPs could induce potential anticancer effects through ROS-mediated apoptosis in MCF-7 cells.

Synthesis approach-dependent antiviral properties of silver nanoparticles and nanocomposites

Numerous viral infections are common among humans, and some can lead to death. Even though conventional antiviral agents are beneficial in eliminating viral infections, they may lead to side effects or physiological toxicity. Silver nanoparticles and nanocomposites have been demonstrated to possess inhibitory properties against several pathogenic microbes, including archaea, bacteria, fungi, algae, and viruses. Its pronounced antimicrobial activity against various microbe-mediated diseases potentiates its use in combating viral infections. Notably, the appropriated selection of the synthesis method to fabricate silver nanoparticles is a major factor for consideration as it directly impacts antiviral efficacy, level of toxicity, scalability, and environmental sustainability. Thus, this article presents and discusses various synthesis approaches to produce silver nanoparticles and nanocomposites, providing technological insights into selecting approaches to generate antiviral silver-based nanoparticles. The antiviral mechanism of various formulations of silver nanoparticles and the evaluation of its propensity to combat specific viral infections as a potential antiviral agent are also discussed.

Antimicrobial and In Vitro Cytotoxic Efficacy of Biogenic Silver Nanoparticles (Ag-NPs) Fabricated by Callus Extract of Solanum incanum L

The in vitro callus induction of Solanum incanum L. was executed on MS medium supplemented with different concentrations of auxin and cytokinin utilizing petioles and explants of leaves. The highest significant fresh weights from petioles and leaf explants were 4.68 and 5.13 g/jar for the medium supplemented with1.0 mg L-1 BA and 1.0 mg L-1 2,4-D. The callus extract of the leaves was used for the green synthesis of silver nanoparticles (Ag-NPs). Analytical methods used for Ag-NPs characterization were UV-vis spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM). Spherical, crystallographic Ag-NPs with sizes ranging from 15 to 60nm were successfully formed. The FT-IR spectra exhibited the role of the metabolites involved in callus extract in reducing and capping Ag-NPs. The biological activities of Ag-NPs were dose-dependent. The MIC value for Staphylococcus aureus, Bacillus subtilis, and Escherichia coli was 12.5 µg mL-1, while it was 6.25 µg mL-1 for Klebsiella pneumoniae, Pseudomonas aeruginosa, and Candida albicans. The highest inhibition of phytopathogenic fungi Alternaria alternata, Fusarium oxysporum, Aspergillus niger, and Pythium ultimum was 76.3 ± 3.7, 88.9 ± 4.1, 67.8 ± 2.1, and 76.4 ± 1.0%, respectively at 200 µg mL-1. Moreover, green synthesized Ag-NPs showed cytotoxic efficacy against cancerous cell lines HepG2, MCF-7 and normal Vero cell line with IC50 values of 21.76 ± 0.56, 50.19 ± 1.71, and 129.9 ± 0.94 µg mL-1, respectively.