Pycnogenol ameliorates depression-like behavior in repeated corticosterone-induced depression mice model.

Oxidative stress is considered to be a mechanism of major depression. Pycnogenol (PYC) is a natural plant extract from the bark of Pinus pinaster Aiton and has potent antioxidant activities. We studied the ameliorative effect of PYC on depression-like behavior in chronic corticosterone- (CORT-) treated mice for 20 days. After the end of the CORT treatment period, PYC (0.2 mg/mL) was orally administered in normal drinking water. Depression-like behavior was investigated by the forced swimming test. Immobility time was significantly longer by CORT exposure. When the CORT-treated mice were supplemented with PYC, immobility time was significantly shortened. Our results indicate that orally administered PYC may serve to reduce CORT-induced stress by radical scavenging activity.