Establishment of cell suspension culture of Lonicera japonica Thunb and analysis its major secondary metabolites

Lonicera japonica Thunb, as a species of honeysuckle native to Asia (including China, Korea, and Japan), is often used for physical fitness due to its extensive biological activity and pharmaceutical properties. The goal of this work was to establish the cell suspension culture of L. japonica as well as to identify and quantify its major secondary metabolites. After sterilized, L. japonica buds, the best explant compared with young stems and leave, can be induced to form yellow friable callus on the MS medium supplemented with 1.5 mg L−1 NAA, 1.0 mg L−1 2,4D, 0.75 mg L-1 KIN and 0.15 mg L−1 BA. The induced callus was transferred on MS medium containing BA 1.5 mg L−1 + NAA 0.2 mg L−1 + 2,4D 0.1 mg L−1, and then sub-cultured three or four times to generate homogenous callus line. A cell suspension system was successfully established, with characteristic of a “S” growth curve and healthy morphology. 3,5-di-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid and 3,4-di-O-caffeoylquinic acid were the main secondary metabolites in the suspension culture cells. The total content of these chlorogenic acids was 22.7 mg g-1 in the suspension cells.