Stimulation of Artemisinin Production in Artemisia annua Hairy Roots by Ag-SiO2 Core-shell Nanoparticles

Silver nanoparticles, exhibiting unusual properties of ionic ability associated with the particle suspension, have been extensively used as the anti-microbial agent in medicine. The present study addressed the elicitation potential of nanosilver particles for the enhancing plant secondary metabolite production. Ag-SiO2 core–shell nanoparticles (AgNPs) with an average size of 101.8 ± 8.9 nm were prepared as elicitor to the hairy root cultures of Artemisia annua. Artemisinin content in the cultures was increased from 1.67 mg/g dry wt to 2.86 mg/g dry wt by the stimulation of AgNPs at 900 mg/L for 3 d. AgNP elicitation was related to the released dissolved Ag+ and nanoparticulate nature of AgNPs introduced to the cultures. AgNP treatment induced oxidative stress (H2O2 production) resulting in lipid peroxidation (increased malonyldialdehyde (MDA) accumulation), enhanced activities of catalase (CAT) and increased artemisinin content in hairy roots. The elicitor stimulated artemisinin production in 20-day-old hairy root cultures up to 13.3 mg/L, a 3.9-fold increase over the control. These results suggest that Ag nanoparticles can be used as a novel effective elicitor in plant biotechnology for the production of plant secondary metabolites.