Antioxidant and acetylcholinesterase inhibition properties of Amorpha fruticosa L. and Phytolacca americana L.

Background: Amorpha fruticosa L. and Phytolacca americana L. are native plants for North America, but invasive for Central Europe and the Mediterranean areas. Previous investigation reported DPPH radical scavenging activity of A. fruticosa seeds from Mississippi river basin and P. americana berries from Iran. The aim of the present study was to investigate methanol extracts from leaves and fruits of these invasive species growing in Bulgaria for radical scavenging and acetylcholinesterase inhibitory potential.

Materials And Methods: Antioxidant activity was investigated using DPPH and ABTS free radicals; FRAP assay and inhibition of lipid peroxidation in linoleic acid system by FTC. Modified Ellman's colorimetric method was carried out to quantify acetylcholinesterase inhibition potential. In addition, the quantities of total polyphenols, flavonoids, and hydroxycinnamic derivatives were determinated using Folin-Chiocalteu reagent, AlCl3, and Na2MoO4, respectively.

Results: The highest concentrations of total polyphenols and flavonoids were found in A. fruticosa leaves (786.70±1.78 mg/g dry extract and 32.19±0.29 mg/g dry extract, respectively). A. fruticosa fruit was found to be the most enriched in total hydroxycinnamic derivatives (153.55±1.11 mg/g dry extract) and demonstrated the highest antioxidant activity: DPPH, IC50 9.83 μg/mL; ABTS, IC50 2.90 μg/mL; FRAP 642.95±3.95 μg TE/mg de, and acetylcholinesterase inhibitory activity, 48.86±0.55% (2 mg/mL).

Conclusions: Phytolacca americana leaves and Amorpha fruticosa could be useful in therapy of free radical pathologies and neurodegenerative disorders.