Anthocyanins in the ripe fruits of Rubus coreanus Miquel and their protective effect on neuronal PC-12 cells.

Phenolics of the fresh ripe fruits of Rubus coreanus Miquel were extracted and separated into anthocyanin and the non-anthocyanin fractions, which were used for the evaluation for antioxidant capacity and neuroprotective effects. The anthocyanin fraction accounted for approximately 47-55% of the total antioxidant capacity of the whole extract and had significantly higher free radical-scavenging capacity than the non-anthocyanin fraction. Furthermore, the anthocyanins alleviated intracellular oxidative stress, as assayed by in vitro fluorescent measurements. The anthocyanins showed neuroprotective effects on PC-12 cells in vitro against oxidative stress in a dose-dependent manner. Triple quadrupole LC/MS and Q-TOF LC/MS analyses revealed four major anthocyanins; cyanidin 3-O-sambubioside, cyanidin 3-O-glucoside, cyanidin 3-O-xylosylrutinoside, and cyanidin 3-O-rutinoside in increasing order of amounts. These results demonstrated that anthocyanins are the major components and contributors to the antioxidant capacity of ripe R. coreanus Miquel fruits. Further studies are warranted to determine whether consumption of the fruits reduces oxidative stress in the brain and promotes health.