Hordenine content of the marine alga Mastocarpus stellatus and the algal food product Carrageen

Hordenine (N,N‐dimethyltryramine) occurs, throughout the year, in the red marine alga Mastocarpus stellatus (Stackh, in With.) Guiry comb, nov., at levels from 1500 μg to 5500 μg/g dry weight. Mastocarpus stellatus constituted 10% to 100% (w/w) of samples of the algal food product Carrageen, the remainder being the red marine alga Chondrus crispus Stackh. The hordenine content of Carrageen samples varied from 10 μg to 1000 μg/g, which was lower than might be expected from the hordenine content of fresh M. stellatus. Studies upon the open air bleaching process used in the production of Carrageen showed it can reduce the hordenine content of M. stellatus by 40% to 90%. However, the hordenine content of some Carrageen may be sufficient to produce adverse pharmacological interactions in some individuals.