The invention discloses a preparation method of
piceatannol. The preparation method comprises the following steps: (1) crushing
passion fruit seeds, adding 50-60 DEG C
aqueous solution the amount of which is twice that of the
passion fruit seeds, adding 0.1-0.5% of biological
enzyme for enzymolysis, adding 50-90%
ethanol solution for
reflux extraction for 2-3 times, recovering the
reagent from the extract and then adding the extract to a
macroporous resin for adsorption, performing
gradient elution by use of the
ethanol solution, concentrating, standing and precipitating the eluate, and filtering to obtain the precipitate; (2) dissolving the precipitate by use of 95%
ethanol, putting the solution through an aluminum
oxide short column, collecting the column passing solution, adding 1-2 times of water by volume, stirring thoroughly and standing for
crystallization, filtering out the crystals, performing
reflux dissolution on the crystals by use of 95% ethanol for recrystallization, and
drying the crystals to obtain the
piceatannol. As the method is used for producing the
piceatannol, the obtained piceatannol is high in purity, and the process is simple and easy to operate, high in extraction efficiency and easy for industrial production.