Bi-, Tri-, and Polycyclic Acylphloroglucinols from Hypericum empetrifolium

Abstract

The ¹H NMR-guided fractionation of a petroleum ether extract of Hypericum empetrifolium led to the isolation of four new bicyclic (1-4), four known bicyclic (5-8), three new tricyclic (9-11), and three new polycyclic acylphloroglucinols (12/13 and 14) possessing a monoterpenoid citran moiety. Compounds 12/13 were isolated as a mixture of two inseparable structural isomers. The compounds showed in vitro antiproliferative activity against human microvascular endothelial cells (HMEC-1) with IC₅₀ values in the range 9.2 ± 2.0 to 29.6 ± 3.5 μM.

Diverse Polyphenols from Hypericum faberi

“…Empetrifranzinan A/B ( 9 / 10 ) have been previously described from Hypericum empetrifolium [ 18 ]. However, the relative configurations of the two compounds were not given in previous literature, and which are demonstrated herein.…”

“…Detailed literature research shows that it has never been phytochemical studied before. To further explore the new and bioactive natural polyphenols from Hypericum species, H. faberi was selected to carry out a phytochemical study and six new polyphenols, hyperfaberols A–F ( 1 – 6 ), together with additional seven known related derivatives 5,7-dihydroxy-2-isopropylchromon ( 7 ) [ 17 ], madeleinol A ( 8 ) [ 18 ], empetrifranzinans A/B ( 9 / 10 ) [ 18 ], otogirin ( 11 ) [ 19 ], dulxanthone D ( 12 ) [ 20 ], and toxyloxanthone B ( 13 ) [ 21 ] were isolated. It’s noteworthy that these isolates can be divided to three group based on their structural characters: isoprenylated xanthones ( 1 – 2 and 12 – 13 ), isoprenylated acylphloroglucinols ( 3 – 5 and 8 – 11 ), and chromones ( 6 – 7 ).…”

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

“…Within this group, some geranylated monocyclic and bicyclic acylphloroglucinol derivatives have been identified that are structurally much more simple than hyperforin. However, they exhibiting potent antiproliferative activity for a human microvascular endothelial cell line (HMEC-1) at low micromolar concentrations [ 57 – 58 ]. Two series of natural-like acylphloroglucinols were synthesized ( Fig.…”

Synthesis and Anti-Inflammatory Activities of Phloroglucinol-Based Derivatives

“…The natural product phloroglucinol ( 1 ) and its derivatives have found a wide range of applications as pharmaceuticals, cosmetics, textiles, paints, and dyes due to their diverse biological activities [1,2]. More than 700 naturally occurring phloroglucinol derivatives have been reported, of which acylphloroglucinol derivatives comprise the largest group [1,3].…”