Main content area

Accumulation of Tilianin and Rosmarinic Acid and Expression of Phenylpropanoid Biosynthetic Genes in Agastache rugosa

Tuan, Pham Anh, Park, Woo Tae, Xu, Hui, Park, Nam Il, Park, Sang Un
Journal of agricultural and food chemistry 2012 v.60 no.23 pp. 5945-5951
Agastache, active sites, amino acid sequences, chalcone isomerase, complementary DNA, flowers, genes, high performance liquid chromatography, leaves, medicinal plants, mint, naringenin-chalcone synthase, quantitative polymerase chain reaction, rapid amplification of cDNA ends, roots, rosmarinic acid, sequence analysis, stems
Korean mint (Agastache rugosa), a perennial, medicinal plant of the Labiatae family, has many useful constituents, including monoterpenes and phenylpropanoids. Among these, tilianin and rosmarinic acid, 2 well-known natural products, have many pharmacologically useful properties. Chalcone synthase (CHS) and chalcone isomerase (CHI) catalyze the first and second committed steps in the phenylpropanoid pathway of plants, leading to the production of tilianin. In this study, cDNAs encoding CHS (ArCHS) and CHI (ArCHI) were isolated from A. rugosa using rapid amplification of cDNA ends (RACE)-PCR. Amino acid sequence alignments showed that ArCHS and ArCHI shared high sequence identity and active sites with their respective orthologous genes. Quantitative real-time PCR analysis was used to determine the expression levels of genes involved in tilianin and rosmarinic acid biosyntheses in the flowers, leaves, stems, and roots of A. rugosa. High-performance liquid chromatography (HPLC) revealed that the accumulation pattern of tilianin matched the expression patterns of ArCHS and ArCHI in different organs of A. rugosa. Moreover, acacetin, the precursor of tilianin, also demonstrated an accumulation pattern congruent with the expression of these 2 genes. The transcription levels of ArPAL, ArC4H, and Ar4CL were the highest in the leaves or flowers of the plant, which also contained a relatively high amount of rosmarinic acid. However, the roots showed a significant content of rosmarinic acid, although the transcription of ArPAL, ArC4H, and Ar4CL were low. The findings of our study support the medicinal usefulness of A. rugosa and indicate targets for increasing tilianin and rosmarinic acid production in this plant.