Cholinesterase inhibitory alkaloids from the rhizomes of <i>Coptis chinensis</i>

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P> <I>Coptis chinensis</I> has been used as a medicinal herb in traditional oriental medicine. In this study, chemical investigation of a water extract of <I>C. chinensis</I> identified two new quaternary protoberberines (<B>1</B>, <B>2</B>), a new tricyclic amide (<B>3</B>), together with five known compounds. Their chemical structures were elucidated by analysis with 1D and 2D NMR and high-resolution mass spectroscopy, as well as by comparison with those reported in the literature. Compounds <B>4</B>, <B>5</B>, and <B>7</B> showed potent inhibition against acetylcholinesterase (AChE) with IC<SUB>50</SUB> values of 1.1, 5.6, and 12.9 μM, respectively. Compounds <B>2</B> and <B>4</B> showed inhibition of butyrylcholinesterase (BChE) with IC<SUB>50</SUB> values of 11.5 and 27.8 μM, respectively. The kinetic activities were investigated to find out the type of enzyme inhibition involved. The types of AChE inhibition shown by compounds <B>5</B> and <B>7</B> were noncompetitive; BChE inhibition by compound <B>2</B> was also noncompetitive.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two new protoberberines and a new amide were isolated from <I>Coptis chinensis</I>. </LI> <LI> Isolated compounds (<B>1−8</B>) were screened for their <I>in vitro</I> ChEs inhibitory effects. </LI> <LI> Compound <B>4</B> showed the most activity on AChE with IC<SUB>50</SUB> values of 1.1 µM. </LI> <LI> Compounds <B>2</B> showed strong inhibition of BChE with IC<SUB>50</SUB> values of 11.5 µM. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>