Synthesis and neuroprotective activity of bergenin derivatives with antioxidant activity Original Research Article

Norbergenin, which is the O-demethyl derivative of bergenin, the main component of Mallotus japonicus, has been found to show moderate antioxidant activity (IC50 13 μM in DPPH radical scavenging; 32 μM in superoxide anion scavenging). Modification of sugar part on norbergenin by coupling with a variety of fatty acids was employed for increasing its antioxidant activity. Selective esterification of hydroxyl groups on the sugar part enhanced greatly antioxidant activity. The most potent one is norbergenin 11-caproate, which not only exhibits stronger antioxidant activity than that of catechin but also prevents neuronal death at 10 μM on the primary culture of rat cortical neurons in DMEM supplemented with N2.