Abstract
The flower of the chrysanthemum plant Shiranui Himekiku has been used as a folk medicine for a variety of diseases including cancer, and cytotoxic effects in some cancer lines have been reported. However, little is known about the anti-cancer activity of the leaf extract and its active compounds. Therefore, to clarify the anti-cancer activity of Shiranui Himekiku leaf and flower, the anti-proliferative effects of the extracts on human cancer cells were examined. Both leaf and flower water extracts dose-dependently suppressed the proliferation of the human breast cancer cell line MCF-7 at concentrations > 25 μg/ml. Furthermore, the anti-proliferative effect in MCF-7 is more than four times that in normal human dermal fibroblast cells. When heated at 100°C for 30 minutes, the proliferation inhibitory activity of the flower extract was unchanged. In contrast, under identical conditions, the activity of the leaf extract was lost. The extracts were separated into two fractions ; one with a molecular weight (MW) > 10 000 (high molecular weight fraction) (HMW) and the other with a MW < 10 000 (low molecular weight fraction) (LMW). A significant proliferation inhibitory effect can be seen in the LMW fraction of both extracts, but the HMW fraction of the leaf extract also slightly inhibits cell growth. Both polyphenols and non-polyphenols are candidate active compounds because the anti-cancer effect was seen in the polyphenol- and non-polyphenol-fractions. These results suggest that the extracts contain several types of anti-cancer components and that both leaves and flowers can be useful.
