Two rearranged acylphloroglucinols with moderate neuroprotective effects from Hypericum ascyron Linn.

Phytochemical studies on the leaves and twigs of Hypericum ascyron Linn. led to the isolation of two previously undescribed rearranged polycyclic polyprenylated acylphloroglucinols (PPAP) with a 4,5- seco -3(2H)-furanone skeleton, named hyperascone A and B (1 – 2). Additionally, a known PPAP tomoeone A (3) and two known xanthones 1,3,5 -trihydroxy-6- O -prenylxanthone (4) and 3,7-dihydroxy-1,6-dimethoxyxanthone (5) were also isolated. The structures of the compounds were determined by the analysis of their spectroscopic data including HRMS, NMR and ECD. All of the five isolated compounds exhibited neuroprotective effects against MPP+ and microglia activation induced damage of SH-SY5Y cells. [Display omitted] • Two new rearranged polycyclic polyprenylated acylphloroglucinols (PPAP) were isolated from Hypericum ascyron. • A possible biosynthetic pathway is proposed based on the Bayer-Villiger reaction. • Some of the compounds showed moderate protective effects against MPP+-induced cell damage. [ABSTRACT FROM AUTHOR]