[Flavonoids from rhizome of Alpinia tonkinensis].

To find out the bioactive principles of Alpinia tonkinensis, by investigating its chemical constituents.It was extracted with MeOH, distributed by different solvents, and isolated via column chromatography on silica gel.Six compounds were elucidated through spectral analysis, which were as follows: 4',7-dimethylkaempferol(I), 5-hydroxy-3',4',7-trimethoxyflavanone(II), kumatakenin(III), 4',5,7-trimethoxyflavonol(IV), ombuine(V), and kaempferol(VI).Six flavonoids were isolated from this plant for the first time, and so were four compounds from genus Alpinia.