Perilla frutescens var. japonica and rosmarinic acid improve amyloid-β25-35 induced impairment of cognition and memory function.

BACKGROUND/OBJECTIVES The accumulation of amyloid-β (Aβ) in the brain is a hallmark of Alzheimer's disease (AD) and plays a key role in cognitive dysfunction. Perilla frutescens var. japonica extract (PFE) and its major compound, rosmarinic acid (RA), have shown antioxidant and anti-inflammatory activities. We investigated whether administration of PFE and RA contributes to cognitive improvement in an Aβ25-35-injected mouse model. MATERIALS/METHODS Male ICR mice were intracerebroventricularly injected with aggregated Aβ25-35 to induce AD. Aβ25-35-injected mice were fed PFE (50 mg/kg/day) or RA (0.25 mg/kg/day) for 14 days and examined for learning and memory ability through the T-maze, object recognition, and Morris water maze test. RESULTS Our present study demonstrated that PFE and RA administration significantly enhanced cognition function and object discrimination, which were impaired by Aβ25-35, in the T-maze and object recognition tests, respectively. In addition, oral administration of PFE and RA decreased the time to reach the platform and increased the number of crossings over the removed platform when compared with the Aβ25-35-induced control group in the Morris water maze test. Furthermore, PFE and RA significantly decreased the levels of nitric oxide (NO) and malondialdehyde (MDA) in the brain, kidney, and liver. In particular, PFE markedly attenuated oxidative stress by inhibiting production of NO and MDA in the Aβ25-35-injected mouse brain. CONCLUSIONS These results suggest that PFE and its active compound RA have beneficial effects on cognitive improvement and may help prevent AD induced by Aβ.