Protective effects of Angelica sinensis extracts against neuronal damage by Amyloid peptide 25-35
Date Issued
2008
Date
2008
Author(s)
Huang, Shih-Hao
Abstract
This study consisting of two experiments investigated the proper processing procedures for preparing the Angelica sinensis (AS) products with various health-promoting functions. The first experiment investigated the effect of extraction conditions on the bioactive components and the functions of the extracts of AS. AS was extracted with water or 20% ethanol for different periods of time, and the antioxidant activity as well as volatile and non-volatile active components in the extracts were determined. The AS extracts contained significant amount of nicotinic acid, phthalic acid, p-coumaric acid, and ferulic acid, and the ferulic acid content was the highest among various phenolic acids in AS extracts. Regardless the water or alcohol extraction, most of the phenolic acids reached their maximum recoveries in 15 minutes. The contents of volatile compounds of AS were much higher in the 20% ethanol extracts than those in water extracts. In the 20% ethanol extracts, the amount of ligustilide (4.403 mg/100 ml), butylidene phthalide (0.187 mg/100 ml) and butyl phthalide (0.147 mg/100 ml) were higher in the 30-min extracts than that prepared for longer time. The inhibition of 1,1-diphenyl-2-picrylhydrazyl (DPPH), lipid peroxidation, and DNA relaxation activities by various AS extracts suggested that, a short extraction time (15 min) produced AS extracts possessing the highest antioxidant effect. The 15-min AS extracts in the concentration range of 20-200 μg/ml also showed inhibitory effects on nitric oxide (NO) production in LPS activated RAW 264.7 macrophage in a dose-dependent manner. The antioxidant activity and phenolic acid concentration for all AS extracts exhibited a positive and significant linear correlation. The second experiment investigated the protective effects of AS extracts against neuronal death by amyloid peptide 25-35 in Neuro 2A cells. Results showed that Aβ25-35 decreased viability of Neuro 2A cells in a concentration dependent manner with IC50 of 14.9 μM. AS extracts reduced Aβ25-35–induced ROS elevation and cytotoxicity in MTT assay. Aβ25-35-induced cellular lipid peroxidation and decreased glutathione levels were also rescued by AS extracts. The Aβ25-35–treated cells showed a significant reduction in the mitochondrial transmembrane potential (m) and mitochondrial dilation with fluorescence probe rhodamin 123 and NAO, respectively in flowcytometry assay. The Neuro 2A cells treated with Aβ25-35 were found to form a membrane-bound degradative vacuole and an enlargement of the mitochondrial mass under TEM observation, suggesting that Aβ25-35-induced cell death was mediated by autophagy. The autophagy-specific inhibitors bafilomycin A1 and 3-methyladenine were used in NAO assay to support the notion. This research further demonstrated that AS extracts possessed a similar activity to bafilomycin A1 and 3-methyladenine on NAO fluorescence suppression, indicating that Angelica sinensis was effective in preventing Aβ25-35 induced neurotoxicity mediated by autophagy. These findings suggested that for obtaining a better flavor product with high anti-oxidative capability and neuroprotective effect activity, we suggest an extraction condition, which was 20% ethanol and less than 30 min extraction time, and the obtained AS extracts was effective in preventing Aβ25-35 induced neurotoxicity mediated by autophagy.
Subjects
Angelica sinensis
beta-amyloid peptide
ROS
ferulic acid
autophagy
NO
Type
thesis
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