Structure of the condensed tannins, flavan-3-ol monomer units, and substrates of tyrosinase.

(1) Chemical structure of the condensed tannins. The 4 to 6 linkage (dotted line) is an alternative interflavan bond. The terminal unit is at the bottom the multi-unit structure. (2) Structure similarities between the flavan-3-ol monomer units and the substrates of tyrosinase.