C. Hartisch et al., DUAL INHIBITORY ACTIVITIES OF TANNINS FROM HAMAMELIS-VIRGINIANA AND RELATED POLYPHENOLS ON 5-LIPOXYGENASE AND LYSO-PAF-ACETYL-COA ACETYLTRANSFERASE, Planta medica, 63(2), 1997, pp. 106-110
In the present study, the effects of tannins obtained from various pla
nt sources on the activity of 5-LOX and AT were examined. With IC50 va
lues ranging from 1.0 to 18.7 mu M, hamamelitannin and the galloylated
proanthocyanidins isolated from Hamamelis virginiana L. were found to
be most potent inhibitors of 5-LOX. Unlike the 5-LOX study, hamamelit
annin proved to be ineffective in the AT assay. Potent candidates are
represented by the group of B-type proanthocyanidins. Structure-activi
ty relationships regarding the in vitro inhibitory potency of the poly
phenols in the biological assays are discussed.