Abstract:Objective: To study the metabolic chemistry and pharmaco-dynamics characters of ligan from seeds of Arctium lappa. Method: HPLC method was used in the study. The analysis was carried out on C18 column. The mobile phase was CH3CN-0.05%H3PO4 (36:64) with flow-rate at 0.6 mL·min-1 and wave-length of 210 nm. The column temperature was kept at 25 ℃. Result: The results indicated that the ligan was detected in plasma and the main organs 5 min after po. The main metabolic production in plasma was arctigenin. In addition, arctigenin and an unknown product were found in metabolic production in the organs. Conclusion: The method was stable, simple and reproducible. It can be used to determine the metabolic product of the ligan. The metabolic chemistry of ligan in plasma was obviously different from that in the main organs.