Abstract
We examined mushrooms for inhibitors of angiotensin I-converting enzyme (ACE). We studied 23 different mushrooms that had shown ACE inhibition by preliminary screening. Of these mushrooms, marked ACE inhibitory activity was observed in Rhodophyllus clypeatus, Lyophyllum semitale, and Pholiota adiposa. Dialysis experiments showed that in mushrooms such as R. clypeatus and L. decastes, the main ACE inhibitor was a low molecular mass molecule. Conversely, the active substances in P. lubrica and Grifola frondosa were high molecular mass molecules, and ACE inhibitors from others species were assumed to contain both elements. It was demonstrated that mushrooms had specific characteristics with respect to their ACE inhibitory substances, and that these are reflected by their taxonomic affiliation at the level of family.
We then isolated ACE inhibitor from R. clypeatus. After extraction with 70% ethanol, we obtained crystals that showed ACE inhibition and identified them to be Nicotianamine. Of the 22 other mushrooms assayed for NA content, only Ramaria botrytis was found to produce this metabolite.
