INHIBITORY EFFECTS OF TANNINS ON NADH DEHYDROGENASES OF VARIOUS ORGANISMS

We examined the effects of purified tannins and related compounds (33 species) on NADH-ubiquinone-1 oxidoreductase activity in four kinds of organism (Paracoccus denitrificans, Bacillus subtilis, Photobacterium phosphoreum, and Thermus thermophilus HB-8) and rat liver mitochondri a. In addition to pentagalloylglucose, which was reported as a potent inhibitor of NADH dehydrogenases (NDH), sanguiin H-11, oolonghomobisfl avan A, and polymerized procyanidin are potent inhibitors for both typ es of NDH (NDH-1 and NDH-2). We found that some other tannins containe d in tea are also inhibitors of NDH from all organisms.