Anti-Zn2+-Toxicity of 4-Hydroxybenzyl Alcohol in Astrocytes and Neurons Contribute to a Robust Neuroprotective Effects in the Postischemic Brain.

4-Hydroxybenzyl alcohol (4-HBA) is an important phenolic constituent of Gastrodia elata (GE) Blume, which is used as a traditional herbal medicine in East Asia. Many activities have been reported to underlie the beneficial effects of 4-HBA in brain, such as, anti-oxidative, anti-inflammatory, anti-excitotoxic, and anti-apoptotic effects in neurons and microglia. Here, the authors demonstrate the robust neuroprotective effects of 4-HBA in rat middle cerebral artery occlusion (MCAO) model of stroke, and showed anti-Zn2+ toxicity in neurons and astrocytes as a molecular mechanism contributing to these effects. Intraperitoneal administration of 4-HBA (20 mg/kg) in Sprague-Dawley rats 1 h after MCAO reduced infarct volumes to 27.1 ± 9.2% of that of MCAO controls and significantly ameliorated motor impairments and neurological deficits. Significant suppressions of Zn2+-induced cell death, ROS generation, and PARP-1 induction by 4-HBA were observed in primary cortical cultures. 4-HBA also protected astrocytes from Zn2+-induced toxicity and suppressing ROS generation by employing slightly different molecular mechanisms, i.e., suppressing PARP-1 induction and NAD depletion under acute Zn2+-treatment and suppressing p67 NADPH oxidase subunit induction under chronic Zn2+-treatment. Results indicate that the protective effects of 4-HBA against Zn2+-toxicity in neurons and astrocytes contribute to its robust neuroprotective effects in the postischemic brain. Considering the pleiotropic effects of 4-HBA, which have been reported in previous reports and added in the present study, it has therapeutic potential for the amelioration of ischemic brain damage.