ALDH1A1 and hepatocellular carcinoma: On the other hand, 3,4-dihydroxyphenylacetic acid (DOPAC), a catabolite of some quercetin glycosides produced by colonic microflora, has been shown to augment the expression of different aldehyde dehydrogenases (ALDH1A1, ALDH2 and ALDH3A1) as well as ALDH activity in the Hepa1c1c7 mouse hepatoma cell line [58].