Abstract: Objective: To explore the protective effect of peptides purified from an enzymatic protein hydrolysate from Agaricus blazei on D-galactose (D-gal)-induced aging in mice. Methods: The peptides were separated by ammonium sulfate precipitation and purified by Sephadex G-50 column chromatography. ICR mice were randomly divided into four groups: blank, model, positive control (piracetam) and Agaricus blazei protein peptide (ABPP) treatment. The aging model was established by injecting D-gal at a dose of 300 mg/(kg mb·d). Morris water maze and step-through tests were used to evaluate the learning and memory ability of mice. The serum levels of total antioxidant capacity (T-AOC), malondialdehyde (MDA), catalase (CAT) and reactive oxygen species (ROS) were detected. The structural changes of hippocampal neurons were observed by hematoxylin-eosin (HE) staining. The mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutamate-cysteine ligase (GCLM) in brain tissues were detected by reverse transcription polymerase chain reaction (RT-PCR). Results: A significant chromatographic fraction from Sephadex G-50 was identified corresponding to a peptide. Compared with the model group, ABPP could significantly shorten the step-through latency and improve learning and memory capacity (P < 0.05 or P < 0.01), accompanied by a significant increase in the serum levels of CAT and T-AOC and a significant reduction in ROS and MDA levels (P < 0.05 or P < 0.01). HE staining results showed that the hippocampal neuron was closely arranged in the ABPP treatment group, and the number of cells with nuclear pyknosis was significantly reduced. The expression mRNA levels of Nrf2, NQO1 and GCLM in the ABPP treatment group were significantly increased (P < 0.05). Conclusion: ABPP can delay the aging process of mice, which may be associated with its anti-oxidation effect.

Key words: peptide extract from Agaricus blazei, D-galactose, aging, antioxidant, nuclear factor erythroid 2-related factor 2/NAD(P)H:quinone oxidoreductase 1