Purification, characterization and neuroprotective effects of a polysaccharide from Gynostemma pentaphyllum

In the present study, we investigated the neuroprotective effects of GPP1, a purified polysaccharide from Gynostemma pentaphyllum, on Aβ (25-35)-induced neuronal toxicity and explore its potential mechanisms in PC12 cells. The results showed pretreatment with GPP1 prior to Aβ (25-35) exposure significantly protected PC12 cells from Aβ (25-35)-induced cell death, lactate dehydrogenase (LDH) release, DNA damage, intracellular free calcium concentration ([Ca(2+)]i) influx, mitochondrial dysfunction and mitochondrial cytochrome c (Cyt-C) release. In addition, pretreatment with GPP1 also protected PC12 cells against Aβ (25-35)-induced the accumulation of reactive oxygen species (ROS) and lipid peroxidation product MDA, the reduction in glutathione (GSH) level and superoxide dismutase (SOD) activity, the increased Bax/Bcl-2 protein expression ratio and caspase-3 activation. Our findings suggest that GPP1 exerts a neuroprotective effect against Aβ (25-35)-induced neurotoxicity in PC12 cells, at least in part, via inhibiting oxidative stress and suppressing the mitochondrial apoptotic pathway.