Anticholinesterase and Antioxidant Effects of Traditional Herbal Medicines used in the Management of Neurodegenerative Diseases in Mauritius
Bioactive plant constituents from traditional herbal medicines can simultaneously protect neurons against oxidative stress and act as cholinesterase inhibitors, two key factors involved in the pathogenesis of neurodegenerative diseases. This study thus aimed at investigating the antioxidant and anticholinesterase activities of five herbal medicines, including 3 polyherbal formulas (F1, F2, F4) and 2 singleherb formulas (F3 and F5), currently used in Mauritius. Antioxidant activities were determined by the reducing potential, scavenging and chelating properties while the pro-oxidant effects was characterized by the copper-phenanthroline assay. While all extracts exhibited antioxidant activity, different extent of such property was observed in each assay. F3 containing Gingko biloba L. demonstrated a higher ferric reducing antioxidant potential (1654 ± 37.8 μmol Fe (II) equivalent/g dry weight) compared to the other extracts. The elixir F2 consisting of Gingko biloba L., Hypericum perforatum L. and Salvia miltiorrhiza Bunge was a potent scavenger of hypochlorous acid and hydroxyl radical and was a strong iron (II) chelator. All extracts inhibited acetylcholinesterase enzyme in a dose-dependent manner, which correlated strongly with total phenolics (r=0.894, p<0.01) and total proanthocyanidins (r=0.937, p<0.01). These findings suggested that activities of the locally available herbal drugs used to slow the progression of neurodegenerative disorder might be partly ascribed to their antioxidant and anticholinesterase activity.
KEY WORDS: Cholinesterase inhibitors; Oxidative stress; Pro-oxidant activities; Traditional herbal medicine; Neurodegenerative diseases