Green synthesis of selenium nanoparticles using Artemisia chamaemelifolia: toxicity effects through regulation of gene expression for cancer cells and bacteria

An effective and economical green procedure is reported for the synthesis of selenium nanoparticles (SeNPs) using the extract of Artemisia chamaemelifolia aerial. The as-synthesized SeNPs were characterized using different spectroscopy and microscopy techniques, confirming the formation of about 110 nm SeNPs capped with phytochemicals present in the Artemisia chamaemelifolia aerial extract. The cytotoxicity of the as-synthesized SeNPs was evaluated through their effects on different bacteria and cell lines. The cytotoxicity effect was tested against the tumorigenic human colorectal adenocarcinoma (HT-29) cell line as well as the low-tumorigenic human embryonic kidney (HEK293) cell line. The results suggested that there is less cytotoxicity against HEK293 cells as compared to HT-29 cells. The apoptosis mechanism was further evaluated by investigation of different anti-apoptotic or pro-apoptotic genes expressed in these two cell lines. For the bacterial toxicity evaluation, S. aureus and K. pneumoniae were used. The results suggested considerable toxicity effect against both studied strains. Similarly, the expression levels of hlaA and vgrG-1 genes were evaluated in pathogenic bacteria after treatment with SeNPs. It was found that SeNPs could down-regulate the expression of pathogenic genes (hlaA and vgrG-1 genes in S. aureus and K. pneumoniae strains, respectively). Based on the findings of this study, we believe SeNPs synthesized by plant extract have great potential to be used for biomedical applications and such a non-metal nanoparticle will open new avenues to future medical applications as an anticancer and antibacterial agent.