【Objective】The active components of Radix peucedani capable of inducing rice resistance to blast disease were separated, purified and identified.【Method】Using activities of inducing resistance to blast disease as an activity monitoring parameter, acetone extract was isolated by silica-gel column to obtain the strongest part of the activity, and the main resistance inducing components from the strongest fractions were separated by using Sephadex LH-20 resin and the structures were analyzed by ultraviolet-vis, infra-red, ESI-MS, 1H-NMR and 13C-NMR spectrums.【Result】Seven fractions from A1 to A7 collected from silica-gel column were tested, A4, A5, A6 had the strongest resistance inducing activities.When the concentrations were 50 mg•L-1, the resistance inducing activities were 55.18%, 59.54%, and 54.36%, respectively. Then three active compounds, Q-1, Q-2, and Q-3, were separated from A4, A5, and A6 through Sephadex LH-20 resin and HPLC. When the concentrations were 10 mg•L-1, the resistance inducing activities of Q-1, Q-2, and Q-3 were 52.77%, 60.76%, and 60.28%, respectively. The spectroscopy analysis indicated that the 3 active components of inducing rice resistance to blast disease of Radix peucedani were peucedanocoumarin Ⅲ, peucedanocoumarin Ⅱ, pteryxin. In addition, peucedanocoumarin Ⅲ was isolated from Radix Peucedani for the first time in China. 【Conclusion】 It is concluded that the coumarin compounds are the most important substance of Radix peucedani capable of inducing rice resistance to blast disease.
