Elicitation of Lonicera japonica Thunb suspension cell for enhancement of secondary metabolites and antioxidant activity

Elicitation has been proved as a very potent tool for enhancing bioactive compounds synthesis in different cell cultures. The current study aimed to explore an efficient elicitation protocol and assess its inducer effect on the accumulation of phytochemical content and antioxidant activity in Lonicera japonica Thunb (L. japonica) suspension cell. Based on a single factor and orthogonal tests, the optimal elicitor combination was 200 μM Me-J, 50 μM SA and 2 h d-1 UV-B. Elicitors had negative effects on cell biomass and luteolin biosynthesis as well as cell color change. The suspension cells, exposed to the optimum elicitor combination, exhibited higher levels in the chlorogenic acids (CGAs) biosynthesis, enzyme activity and antioxidant capacity compared with non-treated control and the field-grown buds. The maximum concentrations were shown on the sixth or seventh day. The increased multiples for each index compared with control and field-grown buds are as follow: 4.52-fold and 3.13-fold of CGAs, 3.05-fold and 6.40-fold of peroxidase(POD), 3.26-fold and 2.56-fold of polyphenol oxidase (PPO), 2.62-fold and 4.91-fold of EC50. DPPH, 3.50-fold and 6.17-fold of EC50.ABTS, 2.55-fold and 7.12-fold of ferric reducing antioxidant power (FRAP), respectively. The results demonstrated that L. japonica cell suspension culture combining with the optimum elicitors has potential applications on commercial production of CGAs and enzymes as well as enhancement antioxidant capacity level.