New compounds from the aerial parts of Calligonum mongolicum

Abstract

• 22 compounds ( 1 - 22 ) were isolated from Calligonum mongolicum . • Chemical structures of previously undescribed compounds 1 and 2 were determined. • A monoterpenoid ( 3 ) was obtained from natural source for the first time. • Catechin ( 7 ) showed insect phenoloxidase inhibitory activity (IC 50 9.1 μM). Previously undescribed compounds, ( R )-4-(4-hydroxyphenyl)-2-butanol 2- O -(6- O -galloyl)-β-D-glucopyranoside ( 1 ) and ( E )-5-(4-hydroxyphenyl)pent-2-enoic acid ( 2 ), together with 20 known compounds ( 3-22 ) were isolated from the aerial parts of Calligonum mongolicum . Compound 3 was obtained from a natural source for the first time, and all of the compounds ( 1 - 22 ) were reported for the first time in this plant. The structural elucidation of compounds 1 and 2 were performed mainly by HRFABMS, HREIMS, 1 H and 13 C NMR, 1 H– 1 H COSY, HMQC, and HMBC spectroscopy. Some of the enzyme inhibitory activities of the isolated compounds were estimated, and catechin ( 7 ) showed ten times higher phenoloxidase inhibitory activity (IC 50 9.1 μM) than epicatechin ( 8 ) (IC 50 148.3 μM). Compounds 7 and 8 have a common molecular structure, except for their stereochemistry, and this result was supported by a reproducibility test using pure guaranteed authentic samples.