Converts 3-phenylpropionate-dihydrodiol (PP-dihydrodiol) and cinnamic acid-dihydrodiol (CI-dihydrodiol) into 3-(2,3-dihydroxylphenyl)propanoic acid (DHPP) and 2,3-dihydroxicinnamic acid (DHCI), respectively. 3-(cis-5,6-dihydroxycyclohexa-1,3-dien-1-yl)propanoate + NAD(+) = 3-(2,3-dihydroxyphenyl)propanoate + H(+) + NADH (2E)-3-(cis-5,6-dihydroxycyclohexa-1,3-dien-1-yl)prop-2-enoate + NAD(+) = (2E)-3-(2,3-dihydroxyphenyl)prop-2-enoate + H(+) + NADH Aromatic compound metabolism; 3-phenylpropanoate degradation. Belongs to the short-chain dehydrogenases/reductases (SDR) family.