Therapeutic potential of Gastrodia elata Blume for the treatment of Alzheimer's disease.

Several studies have demonstrated that the Chinese herb Gastrodia elata Blume can protect against amyloid beta-peptide (Aß)-induced cell death. To investigate the possible therapeutic effects of Gastrodia elata Blume on Alzheimer's disease, we established a rat model of Alzheimer's disease by injecting Aß25-35 into bilateral hippocampi. These rats were intragastrically administered 500 or 1 000 mg/kg Gastrodia elata Blume per day for 52 consecutive days. Morris water maze tests showed that Gastrodia elata Blume treatment significantly improved the spatial memory of Alzheimer's disease rats. Congo red staining revealed that Gastrodia elata Blume significantly reduced the number of amyloid deposits in the hippocampus of these rats. Western blot analysis showed that choline acetyltransferase expression in the medial septum and hippocampus was significantly increased by the treatment of Gastrodia elata Blume, while Ellman method showed significant decrease in the activity of acetylcholinesterase in all three regions (prefrontal cortex, medial septum and hippocampus). These findings suggest that long-term administration of Gastrodia elata Blume has therapeutic potential for Alzheimer's disease.

Gastrodia elata Blume and its pure compounds protect BV-2 microglial-derived cell lines against ß-amyloid: the involvement of GRP78 and CHOP.

OBJECTIVES: Gastrodia elata (GE) Blume (Orchidaceae) has been previously known for its therapeutic benefits against neurodegenerative diseases. Microglial activation and death have been implicated in the pathogenesis of a variety of neurodegenerative diseases, including Alzheimer's disease. In this study, GE and its pure components, gastrodin and 4-hydroxybenzyl alcohol (4HBA), were applied to ß-amyloid-induced BV2 mouse microglial cells. MATERIALS AND METHODS: Cell viability was assessed by the MTT assay and Western blotting was also performed. RESULTS: ß-amyloid-induced cell death was shown to be induced time- and dose-dependently. To examine the cell death mechanism, we confirmed the involvement of ER stress signaling. C/EBP homologous protein (CHOP), a pro-apoptotic ER stress protein, was expressed at high levels but glucose-regulated protein 78 (GRP78), an anti-apoptotic ER stress protein with chaperone activity, was only slightly affected by treatment with ß-amyloid. However, pretreatment with GE and its components inhibited the expression of CHOP but increased that of GRP78 in ß-amyloid-treated cells. This study also showed that a single treatment with GE extracts, gastrodin, or 4HBA induced the expression of GRP78, a marker for enhanced protein folding machinery, suggesting a protective mechanism for GE against ß-amyloid. CONCLUSIONS: This study reveals the protective effects of GE against ß-amyloid-induced cell death, possibly through the enhancement of protein folding machinery of a representative protein, GRP78, and the regulation of CHOP in BV2 mouse microglial cells.