Additional Insights into Hypericum perforatum Content: Isolation, Total Synthesis, and Absolute Configuration of Hyperbiphenyls A and B from Immunomodulatory Root Extracts

Abstract

Phytochemical investigation of the root extracts of Hypericum perforatum led to the isolation of two biphenyl derivatives named hyperbiphenyls A and B (1 and 2) and four known xanthones (3-6). These structures were elucidated by spectroscopic and spectrometric methods including UV, NMR, and HRMS. The absolute configuration of the biphenyl derivatives was defined by two different approaches: biomimetic total synthesis of racemic hyperbiphenyl A followed by H andF NMR Mosher's esters analysis and stereoselective total synthesis of hyperbiphenyl B, permitting assignment of the S absolute configuration for both compounds. The bioactivity of compounds 1-6 toward a set of biomolecules, including major histocompatibility complex (MHC) molecules expressed on vascular endothelial cells, was measured. The results showed that the major xanthone, i.e., 5- O-methyl-2-deprenylrheediaxanthone B (3), is a potent inhibitor of MHC that efficiently reduces HLA-E, MHC-II, and MICA biomolecules on cell surfaces.

Construction of Benzo‐Fused Heterocycles by Epoxide–Heteronucleophile Cyclization: Applications in the Synthesis of Natural Products and Designed Molecules

“…In 2018, Charreau, Derbré, and co‐workers reported a similar strategy for the synthesis of ( S )‐ and ( R )‐Hyperbiphenyls B [15] . Scheme 10 shows the synthesis of ( R )‐Hyperbiphenyl B ( 42 ) from epoxide 41 which, in turn, was advanced from SAD‐delivered diol 40 .…”

Total Synthesis and Anti-inflammatory Activity of Asperjinone and Asperimide C

“…Subsequent oxidation of 7 using m-CPBA in the presence of ptoluenesulfonic acid in CH 2 Cl 2 resulted in the formation of the desired chromanol 4 in 64% yield. 7 With the desired precursors 3 and 4 in hand, we proceeded with Friedel−Crafts alkylation/maleic anhydride formation using Basavaiah's protocol (Scheme 3). Treatment of 3 and 1.7 equiv of 4 with 4 equiv of methanesulfonic acid in dichloroethane at 80 °C for 6 h furnished the requisite asperjinone (1) in 37% isolated yield after purification by reversed-phase preparative HPLC.…”