A prolyl endopeptidase-inhibiting benzofuran dimer from Polyozellus multiflex

A new benzofuran dimer, 5,6,5',6'-tetrahydroxy[3,3']bibenzofuranyl-2,2'-dicarboxylic acid dimethyl ester (kynapcin-24), was isolated from Polyozellus multiflex and shown to noncompetitively inhibit prolyl endopeptidase (PEP), with an IC50 value of 1.14 muM. Kynapcin-24 was less inhibitory to other serine proteases such as chymotrypsin, trypsin, and elastase.