Influence of OH group and sugar bonded to flavonoids on flavonoid-mediated suppression of tumor growth in vitro.

Many flavonoids extracted from higher plants, synthesized or purified flavonoids, and their aglycones showed anti-tumor activity. Using purified or synthesized flavonoids, we studied the effect of the chemical structure of 2-benzoic flavone on the growth of human tumor cells (HCT-15 in vitro. The type of sugar combined with the A phenol of flavonoids played an important role in the tumor suppression; i.e., glucose attachment at the A phenol caused suppression of tumor cell growth, but other sugars such as rhamnose and lutinoside at that position did not suppress the growth of the cells. OH groups bonded to the B phenol also had a great effect on the growth. Flavonoids with OH groups conjugated to the 3', 4', and 5' of B phenol were stronger in anti-tumor effect than those with the OH groups attached at the 3' and 4' or 4' only, although anthocyanins were generally more effective than the other flavonoids.