Comparison of biological activities and chromatographic fingerprints of root extracts from two Acanthopanax species

Root aqueous and 75% ethanolic extracts of Acanthopanax trifoliatus (At) which is called in Thai as phak-paem and Acanthopanax senticosus (As) or Siberian ginseng were tested for in vitro antioxidant activities and inhibitory effect to acetylcholinesterase. It was found that 75% ethanolic refluxing extract from At roots exhibited the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with EC₅₀ value of 33.78±0.70µg/ml while at the concentration of 100µg/ml, aqueous decoction extract from As roots had the highest inhibitory effect (90.65±0.12%) to peroxidation of linoleic acid determined by thiobarbituric acid reactive substances (TBARS) method. However, using ferric reducing antioxidant power (FRAP) assay, all extracts showed similar potency in reducing antioxidant power with FRAP value around 3g FeSO₄ equivalent/100g extract. At the concentration of 2000µg/ml, 75% ethanolic extract from At roots also exhibited the strongest inhibitory effect to acetylcholinesterase using Ellman's method with percentage of inhibition of 97.46±4.41%. High performance liquid chromatography (HPLC) and thin layer chromatography (TLC) of root extracts of At and As showed specific fingerprints suggesting the similar major chemical constituents of phenolic compounds including chlorogenic acid and dicaffeoylquinic acid derivatives.