Improvement of bioactive saponin accumulation in adventitious root cultures of Panax vietnamensis via culture periods and elicitation

Saponin compounds released by Panax vietnamensis into the rhizosphere play critical roles in drug discovery. This study investigated the growth and saponin accumulation of P. vietnamensis adventitious root. Results showed the root growth and productivity of three-saponins (MR2, Rb1, and Rg1) were increased highest on the modified MS medium containing 7 mg/L IBA and 0.5 mg/L BA at 56 days. The root culture divided into three phases: (1) Growth phase 14–56 culture-days; (2) Stationary phase 56–70 days; and (3) Decline phase after 70 days. Saponin accumulation was significantly increased in the treatments of three plant-hormone-elicitors (JA, ABA, and SA), and two cell-wall elicitors (YE and CHN), but five elicitors inhibited formation lateral roots. Although contents of Rg1 (0.32%), Rb1 (0.85%), and MR2 (2.83%) were highest in JA treatment at 0.48 mM, 0.24 mM, and 0.96 mM JA respectively, maximum biomass as well as saponins productivity was observed in 150 mg/L YE. In addition, combination of YE and SA showed effective lower than the solitary YE treatment. The results suggest that adventitious root biomass of P. vietnamensis developed effectively in the modified MS medium after 56 days, and the culture could be scale-up in bioreactor 20 L.