OBJECTIVETo establish and optimize the preparation procedures of the anti-complementary polysaccharides from Houttuynia cordata.

METHODBased on the yield and anti-complementary activity in vitro, the conditions of extraction and alcohol precipitating process were optimized by orthogonal tests. The optimal condition of deproteinization was determined according to the results of protein removed and polysaccharide maintained. The best decoloring method was also optimized by orthogonal experimental design.

RESULTThe optimized preparation procedures were given as follows: extract the coarse powder 3 times with 50 times volume of water at 90 degrees C for 2 hours every time, combine the extracts and concentrate appropriately, equivalent to 0.12 g of H. cordata per milliliter. Add 4 times volume of 90% ethanol to the extract, allow to stand for 24 hours to precipitate totally, filter and the precipitate was successfully washed with anhydrous alcohol, acetone and anhydrous ether. Resolve the residue with water, add trichloroacetic acid (TCA) to a concentration of 20% to remove protein. Decoloration was at a concentration of 3% with activated carbon at pH 3.0, 50 degrees C for 50 min. The above procedures above were tested 3 times, resulting in the average yield of polysaccharides at 4.03% (RSD 0.96%), the average concentrations of polysaccharides and protein at 80.97% (RSD 1.5%) and 2.02% (RSD 2.3%), and average CH50 at 0.079 g x L-(-1) (RSD 3.6%).

CONCLUSIONThe established and optimized procedures are repeatable and reliable to prepare the anti-complementary polysaccharides with high quality and activity from H. cordata.