Growth and triterpenic acid accumulation of Cyclocarya paliurus cell suspension cultures

Abstract

Cyclocarya paliurus is a unique plant growing in central China with hypoglycaemic and hypolipaemia effects. To make better use of this functional food resource, cell suspension cultures and triterpenic acid accumulation were studied. Stable and uniform cell suspension cultures were established in liquid basal Murashige and Skoog medium supplemented with 2,4-dichlorophenoxy acetic acid (0.5 mg/L), naphthalene acetic acid (0.3 mg/L) and cytokinin (1.0 mg/L). According to the growth curve and triterpenic acid accumulation curve, the 8 ∼ 10th day postinoculation was the optimum time for subculture, and the 14th day was the optimum time for harvest. Murashige and Skoog medium and woody plant medium were suitable for both cell growth and triterpenic acid accumulation. 3% sucrose (w/v), 60 mM total nitrogen (NO3−/NH4+ = 2/1), 1.25 mM KH2PO4, 2 mM CaCl2, and 2 mM MgSO4 were all found to be fit for cell growth and triterpenic acid accumulation in a cell suspension culture of Cyclocarya paliurus. Total triterpenic acid, ursolic acid and oleanolic acid content in suspended cultured cells were all significantly higher than that of leaves and calluses (P ⩽ 0.01), with levels up to 6.24, 2.28, and 0.94% (of dry weight), respectively. The betulinic acid content of suspended cultured cells also reached 0.82%, which was significantly higher than that of calluses. These results suggest that suspended cultured cells of Cyclocarya paliurus were rich in triterpenic acids and could be used for the production of total triterpenic acid, ursolic acid, oleanolic acid and betulinic acid.