Cell suspension culture of Orostachys cartilaginous in bioreactor systems for bioactive compound production and evaluation of their antioxidant properties

Abstract

For selecting a suitable culture period during bioreactor culture of Orostachys cartilaginous cells, the kinetics of cell biomass and bioactive compound accumulation were investigated. Cell biomass accumulation had a typical lag phase from 0 to 5 days, an exponential phase from 10 to 25 days, and an obvious declining phase from 25 to 30 days. Total polysaccharide and phenolic accumulation was synchronized with cell growth; their maximum contents were observed at 25 days. Among the flavonoids, quercetin (Qc) and kaempferide (Ke) reached maximum levels at 20 days, whereas the epicatechin gallate (Ecg), quercetin 3-O-glucoside (Qc-3-glc), and kaempferol-3-O-rutinoside (Kp-3-rut) content peaked at 25 days. The suitable culture period of 25 days was confirmed by majority of the observed bioactive compound accumulation. The effect of the air volume was also studied. The cell biomass accumulation was optimal at an air volume of 150 ml min⁻¹. However, the highest content for different bioactive compounds was determined at the varied air volume, i.e., total polysaccharides, total phenolics, and total flavonoids at an air volume of 150 ml min⁻¹, flavonoid monomers of Kp-3-rut at 100 ml min⁻¹, Ke and Ecg at 150 ml min⁻¹, Qc and Qc-3-glc at 200 ml min⁻¹. However, the maximum productivity for all bioactive compounds was at the air volume of 150 ml min⁻¹. The O. cartilaginous cell cultures had higher antioxidant properties. The cell extract concentration providing 50% of 1,1-diphenyl-2-picrylhydrazyl and alkyl radical-scavenging activity were 0.0487 and 0.11 mg ml⁻¹, respectively. Therefore, the bioreactor-cultured cells of O. cartilaginous can be used as potential material sources for production of desirable bioactive compounds and products of O. cartilaginous.