Development of Origanum vulgare Cell Suspension Culture to Produce Polyphenols and the Stimulation Effect of Salicylic Acid Elicitation and Phenylalanine Feeding

Three types of calli were induced from Origanum vulgare ( O. vulgare ) aseptic seedlings, and the friable calli with white appearance and high growth rate were further screened and used to develop cell suspension culture to produce polyphenols. Murashige and Skoog (MS) medium with 3.0 mg/L Kinetin (KT) and 0.5 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) was suitable for both O. vulgare cells growth and polyphenols accumulation. To further enhance the polyphenols accumulation, O. vulgare cells were treated by phenylalanine (Phe) feeding and salicylic acid (SA) elicitation. Compared with the individual Phe feeding and SA elicitation, SA elicitation combined with Phe feeding showed a much better promotion effect on the polyphenols synthesis in O. vulgare cells, especially rosmarinic acid (RosA) accumulation. With the combined treatment of 200 µM SA and 100 µM Phe, total polyphenols content and yield were 41.36 mg/g and 752.93 mg/L, respectively. RosA content and yield reached 31.25 mg/g and 570.37 mg/L, which were 5.44 and 5.47 times that of the control. Furthermore, the total polyphenols extracted from the cultured cells treated by SA elicitation combined with Phe feeding displayed a much higher antioxidant capacity than that of untreated cells, meanwhile its 1,1-diphenyl-2-trinitrophenyl hydrazine (DPPH) and superoxide anion radical-scavenging activity were much stronger than that of vitamin C. What’s more, our results also showed that RosA was the principal contributor to the fine antioxidant capacity of the total polyphenols extracted from the SA and Phe treated cells. Our research indicated that SA elicitation combined with Phe feeding significantly improved the polyphenols yield and antioxidant capacity of the cultured O. vulgare cells, and therefore has a promising application prospect in natural polyphenols production.