Stimulation of phenolic compounds production in Zataria multiflora Boiss. cell suspension culture through salicylic acid elicitation

Zataria multiflora is medicinal plant with a wide range of biological properties due to having phenolic and terpenoid compounds. Induction of secondary metabolites in plant cell culture systems by elicitors is one of the most important strategies to improve the production of medicinal metabolites. In the present study, a cell line was established from Z. multiflora in B5 medium and the effects of salicylic acid at 90, 180 and 360 µM on suspension-cultured cells was evaluated for 3 days in their logarithmic growth phase. The activity of phenylpropanoid biosynthetic pathway and antioxidant enzymes, the level of regulatory molecules hydrogen peroxide (H2O2) and nitric oxide (NO) and also the amount of phenolic compounds were determined by spectroscopy and HPLC techniques. The activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) and also H2O2 and NO content increased in different concentration of elicitor. Salicylic acid at 90 and 180 µM concentrations significantly enhanced the activity of phenylalanine ammonia-lyase (PAL), about 1.2 fold, tyrosine ammonia-lyase (TAL), 1.3 - 1.4 fold and polyphenol oxidase (PPO), 1.5 - 1.7 fold as well as total contents of phenol (5.79 and 4.38 mg g-1 FW) compared to control, respectively. In addition, the production of 4-hydroxy benzoic acid, benzoic acid, epicatechin and syringic acid were induced in Z. multiflora at different concentrations of salicylic acid. This study indicates that Z. multiflora cell suspension culture combined with optimal concentrations of salicylic acid could be a useful and efficient system for sustainable production of valuable secondary metabolites.