Neuroprotective effects of forsythiaside on learning and memory deficits in senescence-accelerated mouse prone (SAMP8) mice.

Forsythiaside (3,4-dihydroxy-β-phenethyl-O-α-L-rhamnopyranosyl-(1→6)-4-O-caffeo yl-β-d-glucopyranoside, C29H36O15), which is isolated from air-dried fruits of Forsythia suspensa, has been shown to possess anti-oxidant, anti-bacterial and anti-inflammatory activities. The aim of this study is to investigate the neuroprotective effects of forsythiaside on learning and memory deficits in the senescence-accelerated mouse prone 8 (SAMP8, a model of age-dependent neurodegenerative disorders such as Alzheimer's disease). Forsythiaside (60, 120 and 240mg/kg) was orally administered to aged (8months old) SAMP8 mice for 45days followed by evaluating cognitive impairment (Morris water maze and step-through passive avoidance), inflammation (interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels), oxidative stress (glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) activities; malondialdehyde (MDA) and nitric oxide (NO) contents) and neurotransmitter such as norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT), glutamate (GLU) gamma-aminobutyric acid (GABA) and acetyl choline (ACh).