New ellagitannins from Tiencha and their inhibitory activity against dental plaque.

Four new galloyl-oxygen-diphenyl (GOD)-type ellagitannins, brambliins A-D (1-4), were isolated from the leaves of Rubus suavissimus. Their structures were elucidated by extensive spectroscopic analyses and the absolute configurations of 1-4 were determined by chemical and phytochemical evidence. These GOD-type ellagitannins inhibited the formation of dental plaque, which is beneficial for oral hygiene.