Optimization of culture medium components and culture period for production of adventitious roots of Echinacea pallida (Nutt.) Nutt

Abstract

To optimize the culture medium for adventitious root (AR) culture of Echinacea pallida, the nitrogen, phosphorus, and sucrose with their different concentrations were combined by using the uniform design method in AR suspension culture. The maximum AR dry weight (5.2 g L−1), phenolic (57.3 mg g−1), and flavonoid (40.8 mg g−1) contents were determined when AR culture medium of the three-quarter strength Murashige and Skoog medium contained 45 mM nitrogen and 1.56 mM phosphorus and was supplemented with 50 g L−1 sucrose and 1 mg L−1 indole-3-butyric acid. Productivities of phenolics and flavonoids of ARs reached 297.9 and 211.9 mg L−1, respectively. The optimized culture medium was used in the AR bioreactor culture. The kinetic study was conducted to select a suitable culture period. When ARs were cultured in a 5-L air-lift bioreactor for 30 days, the accumulation of AR biomass (76.1 g L−1 fresh weight and 7.5 g L−1 dry weight) and bioactive compounds (53.5 mg g−1 phenolics and 37.6 mg g−1 flavonoids) reached the maximum values, and the productivities of phenolics and flavonoids were 398.7 and 280.4 mg L−1, respectively. The bioreactor-cultured AR extracts at 0.8–1.4 mg L−1 inhibited tyrosinase activity, revealing that E. pallida ARs can potentially block melanin formation. Thus, E. pallida ARs has a feasible alternative plant material to be used in the industrial production of whitening cosmetic products.