The Protective Effects And Mechanisms Of Stilbenes On The Primary Cultured Neuronal

Stilbenes are phytoalexins produced under the environment of adversity in different tissues of grapes, peanuts such as the berry (skin and seeds), leaves and canes. As a series of polyphenol compounds, Stilbenes showed a variety of functional activity, such as antioxidation, anti-age, anti-inflammation and so on. In this experiment, the neuroprotective effect of stilbenes have been deeply focused and studied. If so, their structure-activity relationship, dose-effect relationship and mechanism would be studied.In the first part, a primary cultured neuronal β-amyloid-induced damage model was established. The primary cultured neuronal were obtained from fetal rats derived from female rats (E16-18). According to the survival rate of nerve cells, degree, temeperature, does of AP25-35 aggregation and the treating time Aβ25-35 were studied. The result showed that the condition of Aβ25-35 aggregation is dissolution in sterile PBS (pH 7.4) at 37℃ for 14 days. Nerve cells induced by aggregative Aβ25-35 (20 μmol/L) for 24 hours were used to established the stable neuronal damage model.In the second part, four stilbenes with different hydroxyl groups (trans-stilbene, trans-4-hydroxystilbene, trans-resveratrol and piceatannol) were studied. Their acetylcholinesterase-inhibitory activity, antioxidant activity and neuroprotective activity as well as its mechanism have been analyzed and compared. The result showed that above-mentioned activities of stilbenes depend on their chemical structure. Especially, the acetylcholinesterase-inhibitory activity of three stilbenes, other than resveratrol, increased with the number of hydroxyl group; Four stilbenes could effectively remove the DPPH, NO,·OH free radicals and inhibit the production of ROS in the neuronal. In addition, the results of inhibiting ROS production are consistent with that of scavenging-OH free radicals; Four stilbenes exhibited protective effect on Aβ25-35 induced damage nerve cells. The protective mechanism is to inhibit apoptosis through activation the PI3K/Akt/Bad signaling pathway, its downstream mitochondrial and Caspase pathways.In the third part, five stilbenes with different substituent groups (trans-piceid, trans-pterostilbene, 3,4’,5-trimethoxystilbene,δ-viniferin and ε-viniferin) were studied. Their acetylcholinesterase-inhibitory activity, antioxidant activity and neuroprotective activity as well as its mechanism have been focused and analyzed. Our result showed that the above-mentioned activities of stilbenes varied with substituent groups’type and number. In particular, the acetylcholinesterase-inhibitory activity is inversely correlated with their polarity, and this activity of ε-viniferin is much stronger than δ-viniferin; All five stilbenes showed remarkable antioxidant activity, which would effectively remove the DPPH, NO,-OH free radicals. Among the stilbenes with hydroxyl group, the scavenging ability of DPPH radical is positively correlated with the number of hydroxyl group. △-viniferin has the strongest scavenging ability on ·OH free radicals, and this activity maybe related with the position of substituents; All five stilbenes showed prominent inhibitory activity on ROS production in the neuronal, which is consistent with their scavenging ability on ·OH free radicals; As with the neuroprotective effect, only piceid and pterostilbene were focused and studied. They both showed protective activity against neuronal damage, however, with different signaling pathway of resveratrol. For piceid, mitochondrial signaling pathway was activated. For pterostilbene, Caspase pathway was activated. Death receptor pathway and PI3K/Akt/Bad signaling pathway were excluded.