Simultaneous determination of methoxyflavones in selected Korean thistles

Simultaneous determination of three methoxyflavones, namely, cirsimarin (1), hispidulin (2), and cirsimaritin (3) in selected Korean thistles was performed via reversed-phase high performance liquid chromatography system. Compound 1 was present in all the thistle species examined, whereas 2 and 3 were only detected in Cirsium japonicum and C. japonicum var. maackii (CJM). The concentration of compounds 1-3 in CJM varied according to the time of harvest. Plants collected in the spring (CJMS) and fall (CJMF) had the highest contents of 3 and 1, respectively. A lower content of 2 was observed in CJMF than in CJMS. This indicates that seasonal variation affects the flavonoid content of CJM. The results of this study show that CJM is an excellent source of compounds 1-3 and it can potentially be cultivated for industrial and pharmaceutical applications involving these compounds.