Effects of Elicitation on Abeliophyllum distichum Leaf Callus and Changes in Verbascoside Content

Abeliophyllum distichum is a monotypic species in the family Oleaceae that contains a range of phenolic compounds and components such as coumaric acid, catechin, and verbascoside, the latter of which is a major candidate of commercial interest. In this study, we assessed the potential for producing verbascoside using callus culture. To enhance callus productivity in this regard, we evaluated the efficacy of treatment with the elicitors salicylic acid (SA) and methyl jasmonate (MeJA) based on changes in verbascoside content with callus development using Petri dish cultures. Whereas the initial content of verbascoside in A. distichum callus was approximately 50 mg/g, in response to treatment with 50 μM MeJA, we detected an increase to approximately 97.05 mg/g. In contrast, treatment with SA had no significant effects on verbascoside content. In addition, we found that the fresh weight of callus receiving elicitor treatment was lower than that of control callus. Conversely, however, in bioreactor cultures, the fresh weight of callus following treatment with 50μM MeJA for 1 week was higher than that of control callus, and the content of verbascoside in callus treated with 50 μM MeJA was higher than that in control callus. Our findings in this study thus indicate that with appropriate elicitation, the production of verbascoside by A. distichum callus pieces can be enhanced.