Effect of nutritional factors on the accretion of secondary metabolites in Malaysian ginseng adventitious root cultures

Abstract

In this study, we aimed to verify the effect of nutritional factors on the accretion of secondary metabolites in the adventitious root (AR) cultures of Malaysian ginseng (Eurycoma longifolia Jack) grown in small-scale bioreactors. AR were induced from leaf explants and cultured in different types of media including Murashige and Skoog (MS) medium, Driver Kuniyuki Walnut (DKW) medium, Gamborg’s B5 medium, Woody Plant Medium (WPM), and ¾ MS medium. Among these media, the MS and Gamborg’s B5 media induced lateral root development from initial inoculum, which accounted for the increase in AR biomass accretion. By contrast, the DKW and WPM media did not induce lateral root formation from the cultured explants. The ¾ MS medium was optimal for the growth of AR and accretion of secondary metabolites, after 7 weeks of culture, the biomass of AR increased by 8.6-fold in ¾ MS medium, and the total phenolic and flavonoid contents reached 5.23 and 2 mg g−1 of tissue dry weight, respectively. Analysis of mineral elements in the spent medium revealed that ¾ MS medium was most suitable for nutrient supply to developing AR. LC–MS analysis showed the accretion of eurycomanone, a therapeutically useful metabolite, in the AR of Malaysian ginseng.