Enhanced accumulation of total phenolic content and rosmarinic acid in cell suspension cultures of Ehretia asperula using elicitors and precursors

Ehretia asperula, a Vietnamese endemic species known as Xạ Đen, has traditional medicinal applications for conditions such as hepatitis, liver cirrhosis, and cancer. Plant cell suspension cultures provide an alternative approach for producing secondary metabolites. This study focuses on the effects of precursors and elicitors on the accumulation of total phenolic and rosmarinic acid, one of the bioactive compounds presents in E. asperula. Suspension cultures were established using Gamborg (B5) medium supplemented with 1.5 mg L-1 naphthalene acetic acid. Precursors, including L-tyrosine and L-phenylalanine, and elicitors, such as salicylic acid and yeast extract, were added to the culture medium at different concentrations to examine their effects on total phenolic and rosmarinic acid production. The results indicated that precursors and elicitors differentially influenced the accumulation of secondary metabolites and the growth of E. asperula cells. Notably, L-tyrosine was more effective than L-phenylalanine in enhancing biomass and secondary metabolite production after 15 days of culture, with the highest yield observed at 0.5 mg L-1 L-tyrosine. Between the two elicitors tested, yeast extract significantly promoted the production of phenolic compounds and rosmarinic acid, with the highest levels recorded after 12 hours of treatment with 1.0 g L-1 yeast extract. Overall, the findings highlight the potential of E. asperula cell suspension cultures as a substantial source of rosmarinic acid production. The protocol developed in this study offers a promising solution to address the challenges of large-scale production and provides a potential source of raw materials for pharmaceutical, cosmetic, and functional food industries.