Procyanidin B4 is a polyphenol flavonoid dimer of (+)-catechin and (–)-epicatechin that has been found in Q. gilva and has diverse biological activities.1,2 It scavenges DPPH and superoxide radicals (IC50s = 12.15 and 8.67 ?M, respectively).1 Procyanidin B4 inhibits nitric oxide (NO) production in RAW 264.7 macrophages (IC50 = 1.44 ?M). It also inhibits activation of Epstein-Barr virus early antigen (EBV-EA) induced by phorbol 12-myristate 13-acetate in Raji cells.2
1.Youn, S.H., Kwon, J.H., Yin, J., et al.Anti-inflammatory and anti-urolithiasis effects of polyphenolic compounds from Quercus gilva BlumeMolecules22(7)1121(2017) 2.Ito, H., Miyake, M., Nishatani, E., et al.Anti-tumor promoting activity of polyphenols from Cowania mexicana and Coleogyne ramosissimaCancer Lett.143(1)5-13(1999)