The extract of Carpesium cernuum whole plant was successfully used as a green factory for the synthesis of
silver nanoparticles in a one-step, one-pot process. The extract efficiently reduced
silver ions to spherical
silver nanoparticles. The size was measured as 13.0 ± 0.2 nm from high resolution transmission electron microscopic images. The reaction yield was determined to be 99.6% using inductively coupled plasma optical emission spectroscopy. The
silver nanoparticles were highly stable for 28 days at ambient temperature without forming agglomeration or aggregation of nanoparticles. Dose-dependent
antioxidant activity of the
silver nanoparticles was observed in terms of the scavenging activity of
2,2-diphenyl-1-picrylhydrazyl radicals. The
silver nanoparticles also exerted cytotoxicity on Mus musculus skin
melanoma cells (B16F10) and human
lung cancer cells (A549) in a dose-dependent manner. Specifically, the cytotoxicity of the
silver nanoparticles on A549 cells was closely associated with apoptotic cell death. Cellular uptake of the
silver was evaluated via inductively coupled plasma mass spectrometry, and a higher percentage of
silver was taken up by A549 cells (22.6%) than by B16F10 cells (17.3%). This result indicated that higher cellular uptake of
silver nanoparticles resulted in higher cytotoxicity on A549 cells. Therefore,
plant extracts are capable of being valuable natural sources for the green synthesis of
silver nanoparticles that exhibit potent biological activities for pharmaceutical and biomedical applications in future nanomedicine.