In vitro assessment of selected Korean plants for antioxidant and antiacetylcholinesterase activities

Seulah Lee,Dahae Lee,Jiwon Baek,Eun Bee Jung,Ji Yun Baek,Il Kyun Lee,Tae Su Jang,Ki Sung Kang,Ki Hyun Kim

doi:10.1080/13880209.2017.1397179

Abstract

Context: Antiacetylcholinesterase (AChE) drugs have been a main therapeutic treatment for Alzheimer’s disease because increased AChE levels play a key role in reducing neurotransmission.Objectives: Extracts from 35 Korean plants were selected and screened for antioxidant and anti-cholinesterase activity to explore new sources derived from Korean natural resources that could be used as AD therapeutic agents.Materials and methods: The antioxidant effect of extracts from 35 selected Korean plants was determined using two most common free radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS). Additionally, the effect of extracts, identified as antioxidants, on acetylcholinesterase inhibition was assessed by an acetylcholinesterase assay kit.Results: Out of 36 extracts of 35 plants tested, Oenothera biennis L. (9.09 μg/mL), Saururus chinensis (Lour.) Baill. (9.52 μg/mL) and Betula platyphylla var. japonica (9.85 μg/mL) showed strong DPPH scavenging activity. Twelve other extracts also exerted moderate free radical scavenging activities with IC50 values ranging from 10 to 50 μg/mL. Antioxidant capacity detected by ABTS assay was only significant in O. biennis (23.40 μg/mL), while the other extracts were weak or unable to reduce the production of ABTS. Based on the antioxidant activities of these plant extracts, 19 extracts with IC50 values less than 100 μg/mL in DPPH assay were selected for further AChE inhibition assay. Among the extracts tested, the IC50 value for Prunella vulgaris var. lilacina NAKAI (18.83 μg/mL) in AChE inhibitory activity was the lowest, followed by O. biennis (20.09 μg/mL) and Pharbitis nil Chosy (22.79 μg/mL).Conclusions: Considering complex multifactorial etiology of AD, the extracts of P. vulgaris var. lilacina (aerial part), O. biennis (seed) and P. nil (seed) may be safe and ideal candidates for future AD modifying therapies.

Highlights

Alzheimer’s disease (AD), a progressive age-related disease of the central nervous system (CNS), is characterized by deterioration in neurological function (Bartzokis 2004; Adewusi et al 2011)
Free radical scavenging activity of the extracts using DPPH and ABTS assay Multiple factors are involved in the development of neurodegenerative disease
IC50 values for DPPH radical scavenging were determined based on the concentration of the extract required for approximately 50% of the original activity

Summary

Introduction

Alzheimer’s disease (AD), a progressive age-related disease of the central nervous system (CNS), is characterized by deterioration in neurological function (Bartzokis 2004; Adewusi et al 2011). Oxidative stress is known to be a key factor in the aging process Since this is associated with Ab plaque deposition which causes neuronal oxidative stress in AD patients, it is considered as a main pathogenesis cause of AD (Adewusi et al 2011; Zhao et al 2013). It was previously reported that reactive oxygen species (ROS) play an important role in neurodegenerative diseases (Zhao et al 2013), and eventually contribute to neuronal death, causing impaired memory, cognitive ability and behavioral problems (Ali et al 2015; Haque and Nazir 2016; Wu et al 2017)

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