Evaluation of the inhibitory effect of various drugs / active ingredients on the activity of human diamine oxidase in vitro

Background In this study the influence of active ingredients of certain drugs on the activity of human diamine oxidase (DAO; EC 1.4.3.22) was quantified. DAO is the main enzyme in catabolism of biogenic amines in the intestine. Ingestion of food containing high amounts of biogenic amines in case of reduced activity of DAO leads to an accumulation of histamine which causes symptoms of histamine intolerance. Many drugs are suspected to inhibit DAO-activity, nevertheless, only few scientific data are available to support this thesis.