Biochem/physiol Actions: A plant flavonoid that has been found to inhibit cell proliferation by arresting the cell cycle at the G2 /M phase. Inhibition of growth through cell cycle arrest and induction of apoptosis appear to be related to induction of p53. Inhibitory effects on tumor promotion may also be due to inhibition of kinase activity and the resulting suppression of oncogene expression. It has also been reported to inhibit topoisomerase I catalyzed DNA religation and enhance gap junctional intercellular communication.