In vitro inhibition of adenosine deaminase by flavonoids and related compounds. New insight into the mechanism of action of plant phenolics.

The effects of 20 flavonoids, anthocyanes and other phenolic compounds of plant origin have been tested in vitro for their inhibitory effect on the enzyme adenosine deaminase (ADA). Significant effects were obtained with most compounds at concentrations between 0.0001 and 0.1 mg/mI. Thus, plant phenolics can be considered as natural ADA enzyme inhibitors. It is assumed that they also increase the actual adenosine (Ado) concentration in vivo. This may explain many of the pharmacological activities of these compounds on a molecular basis.