Establishment of culturing conditions and assessment of antioxidant activity and somaclonal variation in the adventitious root suspension cultures of Oplopanax elatus Nakai

Oplopanax elatus Nakai, a plant traditionally used in folk medicine, is currently in population decline due to uncontrolled harvesting. In the present study, we investigated the factors affecting O. elatus adventitious root production, including hormones (alone or in combination), explant type, basal salt type and strength, sucrose concentration, pH, and temperature. Results revealed that adventitious root formation was optimal with root explants grown on 1/2 Murashige and Skoog (MS) medium containing 0.5 mg L^?1 Indole-3-butyric acid (IBA) (pH 5.8) at 25 °C. Chlorogenic acid concentration was highest in roots propagated in 1/2 MS medium containing 0.5 mg L^?1 IBA; vanillin, another phenolic compound, was also detected in cultures. Liquid media containing 3% sucrose exhibited the highest radical scavenging activity and total phenolic compound contents. X-ray diffraction revealed significant differences in the elemental intensity between adventitious root and field-grown plantlet extracts. Analysis of simple sequence repeats confirmed that adventitious roots regenerated in vitro were genetically similar to their mother plant. Thus, we identified the optimal conditions for proliferation of O. elatus adventitious roots in liquid culture, from which, secondary metabolites, particularly bioactive compounds associated with the medicinal use of this plant, can be mass produced without further population deterioration.