Hydrogen peroxide Acts as a Secondary Messenger for Production of Silymarin in Ag+ Elicited Silybum marianum Hairy Root Cultures

This study was performed to investigate the effect of Ag+ as an elicitor on the activity of antioxidant enzymes, content of H2O2, accumulation of total tocopherol and antioxidant activity in hairy root cultures of Silybum marianum (L.) Gaertn. The hairy roots were treated with 2 mM Ag+. The treated and non-treated hairy roots were harvested in the same time and data on H2O2 content, DPPH, tocopherol content and enzyme activity were measured. Ag+ elicitation resulted in enhanced H2O2 content after 24, 72 and 96 h. Peroxidase activity increased 24 h after elicitation, whereas the antioxidant activity decreased upon treatment. The overall trend of IC50 changes was very similar to that of the control treatments. Tocopherol content decreased 24 and 48 h after elicitation. The results demonstrated a possible role of hydrogen peroxide as a secondary messenger for production of silymarin in Ag+ elicited Silybum marianum hairy roots cultures.