Effects of chemically defined tannins on poly (ADP-ribose) glycohydrolase activity.
Three classes of chemically defined tannins, gallotannins, ellagitannins and condensed tannins were examined for their inhibitory activities against purified poly (ADP-ribose) glycohydrolase. Ellagitannins showed higher inhibitory activities than gallotannins. In contrast, condensed tannins, which consist of an epicathechin gallate (ECG) oligomer without a glucose core were not appreciably inhibitory. Kinetic analysis revealed that the inhibition of ellagitannins was competitive with respect to the substrate poly(ADP-ribose), whereas gallotannins exhibited mixed-type inhibition. These results suggest that conjugation with glucose of hexahydroxy-diphenoyl (HHDP) group, which is a unique component of ellagitannins, potentiated the inhibitory activity, and that the structure of ellagitannins may have a functional domain which competes with poly(ADP-ribose) on the poly(ADP-ribose) glycohydrolase molecule.
Tsai
Y J
YJ
Department of Pharmacology, Faculty of Medical Sciences, Taipei Medical College, Taiwan, R.O.C.
Abe
H
H
Maruta
H
H
Hatano
T
T
Nishina
H
H
Sakagami
H
H
Okuda
T
T
Tanuma
S
S
D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors*; D007700:Kinetics; D013329:Structure-Activity Relationship; D013634:Tannins / Q000737:chemistry / Q000494:pharmacology*
D013634:Tannins; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase