Isolation of four new pterocarpans from Zygophyllum eurypterum (syn. Z. atriplicoides) with enzyme-inhibition properties

Abstract

Four new pterocarpans, atricarpan A (=(-)-1,2-dihydroxy-4-(hydroxymethyl)-3,9-dimethoxy-pterocarpan; 1), atricarpan B (=(-)-2,3-ethylenedioxy)-1,4-dihydroxy-9-methoxypterocarpan; 2), atricarpan C (=(-)-1,9-dimethoxypterocarpan-3-carboxylic acid; 3), and atricarpan D (=(-)-2,9-dimethoxy-4-(5-oxohexyl)pterocarpan; 4) were isolated from the BuOH extract of the whole plant of Zygophyllum eurypterum. The structure elucidations of those compounds were based primarily on 1D- and 2D-NMR analysis, including COSY, HMBC, and HMQC correlations, Compounds 1-4 also inhibited butyrylcholinesterase (BChE; EC 3.1.1.8) enzyme in a concentration-dependent manner with IC50 values between 12.5-65.0 μM. Similarly, compounds 1 and 4 inhibited lipoxygenase (LOX; EC 1.13.11.12) and acetylcholinesterase (AChE; EC 3.1.1.7) enzymes with IC50 values of 13.5 and 20.5 μM, respectively. © 2006 Verlag Helvetica Chimica Acta AG, Zürich.