Inhibitory Effects of Bark Proanthocyanidins on the Activities of Glucosyltransferases of Streptococcus Sobrinus

Seventy percent acetone aqueous extracts of Acacia mearnsii and Larix spp. bark inhibited the activity of glucosyltransferase (GTase) derived from Streptococcus sobrinus to a greater degree than green tea or oolong tea extracts. The GTase inhibitory activity increased as the molecular weight of proanthocyanidins contained in the extracts increased. The GTase inhibition was very closely related to the hydroxylation patterns in the B-rings of synthesized proanthocyanidins, where compound with a catechol ring showed high activity than with a pyrogallol B-ring, and it was a non-competitive type of inhibition.