Effects of molecular weight and hydrolysis conditions on anticancer activity of fucoidans from sporophyll of Undaria pinnatifida

Hydrolyzed fucoidans, from sporophyll of Undaria pinnatifida, were used to determine the effects of molecular weight (Mw) and hydrolysis conditions on cancer cell growth. Native fucoidans showed anticancer activity of 37.6%. When hydrolyzed in boiling water with HCl for 5 min, fucoidans (Mw = 490 kDa) significantly increased anticancer activity to 75.9%. However, fucoidans hydrolyzed in a microwave oven showed little improvement of anticancer activity and even exhibited the inhibition activity below 30% when treated more than 90 s. This suggests that anticancer activity of fucoidans could be significantly enhanced by lowering their Mw only when they are depolymerized by mild condition.