Method for preparing total flavonoids, total tannins and galic acid compounds of polygonum capitatum

The invention relates to a method for preparing total flavonoids, total tannins and galic acid compounds of polygonum capitatum. The method comprises the following steps: quenching polygonum capitatum by 40 to 80 percent ethanol (methanol or acetone) or coating refluxed extract on D101 macroporous resin, eluting the polygonum capitatum by 70 to 85 percent ethanol (or methanol), coating concentrated eluant on an MCI column, eluting the MCI column by water, performing water solution and alcohol precipitation after concentrating the eluant, and obtaining the galic acid compounds when concentrating supernatant liquid to extractum; eluting the galic acid compounds by 80 percent ethanol (or 85 percent methanol), concentrating the eluant to extractum, after dissolving the extractum by 95 percent ethanol, coating the solution on a SephadexLH-20 gel column, eluting the gel column by 95 percent ethanol to colorlessness, and obtaining the total flavonoids when concentrating the eluant to extractum ...