Enhanced biosynthesis of saponins by coronatine in cell suspension culture of Kalopanax septemlobus .

Kalopanax septemlobus is a medicinal woody species of the family Araliaceae, and the pharmaceutical properties of saponins obtained from K . septemlobus suggest that K . septemlobus has the potential to be a crude drug and dietary health supplement. In this study, we established cell suspension culture of K . septemlobus to develop a sustainable source of natura-ceuticals. Friable calli were used for establishing cell suspension culture. The maximum amount of total saponins (1.56 mg/60 ml suspension) was obtained during the 15th day of incubation, whereas the maximum capacity of saponin production was reached after day 6 (0.42 μg/mg of fresh weight). The total saponin production in the cell suspension of K . septemlobus was significantly increased by coronatine (COR) at 160% at a dose of 1 μM compared with the mock-treated control, whereas methyl jasmonate treated cells exhibited less increase in total saponin level as compared to the COR-treated cells. In addition, the elicitation of COR strongly induced the expression of beta-amyrin synthase, thus resulting in the accumulation of oleanolic acid (2.369 ± 0.98 μg/mg of extract), a precursor for oleanane-type triterpene saponins. These results indicate that COR is an efficient elicitor for inducing phytochemicals in cell suspension culture and that it provides the possibility for producing saponins of K . septemlobus using cell suspension culture.