Lactuca undulata Ledeb. is a medicinal plant belonging to the Asteraceae family. Chicoric acid is one of the main derivatives of caffeic acid, with various pharmacological and biological properties. This study was conducted to optimize cell suspension culture and enhance chicoric acid production in L. undulata by eliciting secondary metabolites using silver nitrate (AgNO۳) and silver nanoparticles (AgNPs). Seeds were cultured on ½ MS medium to produce sterile seedlings. In order to produce callus, leaf and root explants were obtained from ۲ months old sterile seedlings and placed on ½ MS medium containing ۲ mg/L ۲,۴-D/ plus ۰,۵ mg/L Kin and ۲ mg/L ۲,۴-D/ plus ۲ mg/L Kin, respectively. Cell suspension cultures from leaf and root-derived calluses were established and treated with different concentrations (۰, ۲, and ۴ mg/L) of AgNO۳ and AgNPs during the logarithmic growth phase. Then cells were harvested after ۲۴, ۴۸, and ۷۲ hours. Overall, elicitation by AgNPs was more effective on chicoric acid production compared to AgNO۳. The highest amounts of chicoric acid (۹,۷ ± ۰.۴۸ mg/g DW) and caffeic acid (۱۵.۳ ± ۰.۸ mg/L) were found in leaf and root cell suspension cultures after ۴۸ hours of exposure to ۴ and ۲ mg/L AgNPs, respectively. In contrast, ۴ mg/L of AgNO۳ stimulated the greatest accumulation of chlorogenic acid (۴,۵۶ ± ۰.۳ mg/g DW) in root cell culture at ۷۲ h after elicitation. The current results revealed that the use of AgNPs can be an efficient strategy to improve cichoric acid accumulation in cell suspension culture.
