Salicylic acid induces the change in the adventitious root of Glycyrrhiza uralensis Fisch.: bioactive compounds and antioxidant enzymes

In this study, adventitious roots of Glycyrrhiza uralensis were cultured in a 5-L balloon-type bubble bioreactor with different medium salt strength and different concentrations of sucrose. The results of the culture showed that the best culture conditions were 4 % sucrose concentration and 1 MS medium for the accumulation of secondary metabolites. Salicylic acid has previously been used as an elicitor in tissue cultures to enhance production of secondary metabolites. Addition of 1 mg L-1 salicylic acid significantly enhanced the contents of glycyrrhizic acid (0.31 mg g(-1)), glycyrrhetinic acid (0.14 mg g(-1)) and polysaccharide (159.29 mg g(-1)) in the G. uralensis adventitious roots and the contents were 2.58-fold, 1.27-fold, and 2.07-fold over the control group. Furthermore, the greatest content of total flavonoid (9.40 mg g(-1)) was observed with 2 mg L-1 salicylic acid added in the culture, which was 2.68-fold higher than the control. The ESI-MSn analysis was also performed, showing that two new kinds of flavonoids, including (3R)-vestitol and glycyrol, were only identified in the salicylic acid treatment. In addition, we also found that salicylic acid significantly increased superoxide dismutases, catalases, and peroxidase activity.