Pycnogenol Improves Learning Impairment and Memory Deficit in Senescence-Accelerated Mice

Pycnogenol (procyanidins extracted from the bark of French maritime pine, Pinus maritima Aiton) has been shown to be a potent free radical scavenger and an antioxidant phytochemical. The effects of pycnogenol on learning impairment and memory deficit in senescence-accelerated mouse (SAM) as a murine model of accelerated aging were determined. SAMP8, a strain of senescence-prone mice, exhibits immunodeficiency, hemopoietic dysfunction, learning impairment, and memory deficit. The effects of pycnogenol on learning performance and memory deficit were measured using step-through and step-down passive avoidance tests and shuttle box conditioned avoidance test. Oral feeding with pycnogenol for 2 months increased the retention rate in the step-through and the step-down tests and the rate of conditioned avoidance response in the shuttle box test. The latency of mice in the step-through test and the number of successful mice in the step-down test also increased with pycnogenol feeding. These results suggest that pycnogenol can improve learning impairment and memory deficit associated with aging.