Phthalide-derived oxaspiroangelioic acids A-C with an unprecedented carbon skeleton from an aqueous extract of the Angelica sinensis root head

Three phthalide-derived analogues, oxaspiroangelioic acids A-C (1-3), were isolated as minor components of an aqueous extract of the Angelica sinensis root heads (guitou). Oxaspiroangelioic acids A and B were racemates separated into enantiomers by chiral HPLC. Their structures including absolute configurations were determined by spectroscopic data analysis, single crystal X-ray diffraction, exciton chirality method and electronic circular dichroism (ECD) calculation. These compounds share an undescribed carbon skeleton, for which biosynthetic pathways are proposed. Compound 1 and its enantiomers showed almost identical activity inhibiting Tandem of P domains in a weak inwardly rectifying K+ channel 1 (TREK-1). (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

Three phthalide-derived analogues, oxaspiroangelioic acids A-C, were isolated from aqueous extract of Angelica sinensis root heads. Oxaspiroangelioic acids A and B were separated into enantiomers by chiral HPLC. They share similar inhibiting activity and may be biosynthesized through novel pathways.