Neuroprotection of a Novel Synthetic Caffeic Acid-Syringic Acid Hybrid Compound against Experimentally Induced Transient Cerebral Ischemic Damage

We investigated effects of caffeic acid, syringic acid, and their synthesis on transient cerebral ischemic damage in the gerbil hippocampal CA1 region. In the 10 mg/kg caffeic acid-, syringic acid-, and 20 mg/kg syringic-treated ischemia groups, we did not find any significant neuroprotection in the ischemic hippocampal CA region. In the 20 mg/kg caffeic acid- and 10 mg/kg caffeic acid-syringic acid-treated ischemia groups, moderate neuroprotection was found in the hippocampal CA1 region. In the 20 mg/kg caffeic acid-syringic acid-treated ischemia group, a strong neuroprotective effect was found in the ischemic hippocampal CA1 region: about 89 % of hippocampal CA1 region pyramidal neurons survived. We also observed changes in glial cells (astrocytes and microglia) in the ischemic hippocampal CA1 region in all the groups. Among them, the distribution pattern of the glial cells was only in the 20 mg/kg caffeic acid-syringic acid-treated ischemia group similar to that in the sham group (control). In brief, 20 mg/kg caffeic acid-syringic acid showed a strong neuroprotective effect with an inhibition of glia activation in the hippocampal CA1 region induced by transient cerebral ischemia.