<i>In vitro</i> assessment of selected Korean plants for antioxidant and antiacetylcholinesterase activities

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P><P><B>Context:</B> Antiacetylcholinesterase (AChE) drugs have been a main therapeutic treatment for Alzheimer’s disease because increased AChE levels play a key role in reducing neurotransmission.</P><P><B>Objectives:</B> 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.</P><P><B>Materials and methods:</B> 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.</P><P><B>Results:</B> Out of 36 extracts of 35 plants tested, <I>Oenothera biennis</I> L. (9.09 μg/mL), <I>Saururus chinensis</I> (Lour.) Baill. (9.52 μg/mL) and <I>Betula platyphylla</I> var. <I>japonica</I> (9.85 μg/mL) showed strong DPPH scavenging activity. Twelve other extracts also exerted moderate free radical scavenging activities with IC<SUB>50</SUB> values ranging from 10 to 50 μg/mL. Antioxidant capacity detected by ABTS assay was only significant in <I>O. biennis</I> (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 IC<SUB>50</SUB> values less than 100 μg/mL in DPPH assay were selected for further AChE inhibition assay. Among the extracts tested, the IC<SUB>50</SUB> value for <I>Prunella vulgaris</I> var. <I>lilacina</I> NAKAI (18.83 μg/mL) in AChE inhibitory activity was the lowest, followed by <I>O. biennis</I> (20.09 μg/mL) and <I>Pharbitis nil</I> Chosy (22.79 μg/mL).</P><P><B>Conclusions:</B> Considering complex multifactorial etiology of AD, the extracts of <I>P. vulgaris</I> var. <I>lilacina</I> (aerial part), <I>O. biennis</I> (seed) and <I>P. nil</I> (seed) may be safe and ideal candidates for future AD modifying therapies.</P>