Kudzu flowers were crushed and weighed 300g, respectively, extracted with 900 mL of methanol in cold soak for three times, and the combined extracts were concentrated under reduced pressure. The methanol extract was suspended in appropriate amount of distilled water, firstly extracted with benzene to degrease, then extracted with n-butanol, the n-butanol extract was concentrated to dryness, eluted by silica gel column chromatography with CHCl3:CH3OH ( 10:1), and obtained light yellow snowflake crystals (methanol recrystallization), that is, to obtain the kudzuoside.
