Antiproliferative Activities of Water Infusions from Leaves of Five Cornus L. Species

Cornaceae plants are known for their edible berries, and their leaves are used as tea. In the present study aqueous leaf extracts from Cornus mas (CM), C. alba (CA), C. flaviramea (CF), C. kousa (CK), and C. officinalis (CO) were tested for their antiproliferative activity in human breast cancer cells (MCF-7). Dose- (50–750 µg/mL) and time (24, 48, 72 h)-dependent antiproliferative effects were measured by WST-1, and correlated with the content of flavonoids (FL), total hydroxycinnamic derivatives (THD), total polyphenols (TP) and tannins (T). Extracts induced time dependent decreases in cell survival; CA, CO and CM were the most effective (11.2%, 10.3% and 11.1%, after 72 h). The ED50 (effective dose) values were similar for all extracts and times tested. The THD and TP were identical in all samples, while a two-fold higher T content was present in CK and CO, and of FL in CF. The maximal effects (% of surviving cells) negatively correlated with the T and TP levels, and positively with FL and THD. The results demonstrate the significant antiproliferative effects of the tested water extracts in MCF-7 cells, in which CA, CO and CM are the most effective; and the effectiveness is related to the T and TP contents.