HEALTH NEWS

Study Title:

Nobiletin, a citrus flavonoid, ameliorates cognitive impairment

Study Abstract

Senescence-accelerated mouse prone 8 (SAMP8) is a model of aging characterized by the early onset of learning and memory impairment and various pathological features of Alzheimer's disease (AD). Our recent studies have demonstrated that nobiletin, a polymethoxylated flavone from citrus peels, ameliorates learning and memory impairment in olfactory-bulbectomized mice, amyloid precursor protein transgenic mice, and NMDA receptor antagonist-treated mice. Here, we present evidence that this natural compound improves age-related cognitive impairment and reduces oxidative stress and tau phosphorylation in SAMP8 mice. Treatment with nobiletin (10 or 50mg/kg) reversed the impairment of recognition memory and context-dependent fear memory in SAMP8 mice. Treatment with nobiletin also restored the decrease in the GSH/GSSG ratio in the brain of SAMP8 mice. In addition, increases in glutathione peroxidase and manganese-superoxide dismutase activities, as well as a decrease in protein carbonyl level, were observed in the brain of nobiletin-treated SAMP8 mice. Furthermore, nobiletin reduced tau phosphorylation in the hippocampus of SAMP8 mice. Together, the markedly beneficial effects of nobiletin represent a potentially useful treatment for ameliorating the learning and memory deficits, oxidative stress, and hyperphosphorylation of tau in aging as well as age-related neurodegenerative diseases such as AD.

Study Information

Nakajima A, Aoyama Y, Nguyen TT, Shin EJ, Kim HC, Yamada S, Nakai T, Nagai T, Yokosuka A, Mimaki Y, Ohizumi Y, Yamada K.
Nobiletin, a citrus flavonoid, ameliorates cognitive impairment, oxidative burden, and hyperphosphorylation of tau in senescence-accelerated mouse.
Behav Brain Res.
2013 August
Department of Neuropsychopharmacology and Hospital Pharmacy, Graduate School of Medicine, Nagoya University, Tsuruma-cho, Showa-ku, Nagoya 466-8560, Japan.