Method for preparing syringic acid from spiral seaweed

The invention discloses a method for preparing syringic acid from spiral seaweed. The method comprises the following steps: step one, carrying out digestion on a spiral seaweed crude extract with diethyl ether; step two, carrying out first separation and purification on the crude extrude with a glucan gel column; step three, carrying out second separation on the crude extract with a reverse phasesilica gel column; step four, carrying out third separation on the crude extract with the glucan gel column; step five, carrying out fourth separation on the crude extract with the reverse phase silica gel column; step six, carrying out fifth separation on the crude extract with a positive phase silica gel column to obtain a compound A; and step seven, structurally identifying the compound A as syringic acid, thereby obtaining the syringic acid. According to the method, the syringic acid is separated from the spiral seaweed for the first time, the syringic acid serves as an active ingredient of spiral seaweed, and the