Additional Constituents of Hypericum Subalatum

Abstract

The whole herb of Hypericum subalatum Hayata contains three flavonoids, caffeic acid esters, a pyranoxanthone, and three xanthines, in addition to the previously reported xanthonolignoids. Among these compounds, 2,7‐dihydroxy‐3,4‐dimethoxyxanthone has not been described in the literature before. The co‐occurrence of xanthone derivatives and flavonoids in this plant is of chemotaxonomic significance.

Quercetin as the Active Principle ofHypericumhircinumExerts a Selective Inhibitory Activity against MAO-A: Extraction, Biological Analysis, and Computational Study

“…After this assessment the extract was first partitioned between CH 2 Cl 2 and H 2 O, and the aqueous layers were fractionated by VLC, subsequent CC, and HPLC (RP-18) to afford quercetin ( 1 ), eriodictyol ( 3 ), 1,6-dihydroxy-5,7-dimethoxyxanthone ( 5 ), and (4 R )-4-hydroxy-5,5-dimethyldihydrofuran-2-one ( 6 ) from the CH 2 Cl 2 phase and quercetin-3‘- O -β- d -glucopyranoside ( 2 ) and eriodictyol-7- O -β- d -glucopyranoside ( 4 ) from the aqueous soluble part (Figure ). The physical and spectroscopic data agree with those reported, − and although compound 6 has been obtained by synthesis, it is isolated for the first time as a natural product. Complete NMR data for compound 5 are reported…”

“…The ability of the total MeOH crude extract of H. hircinum leaves to inhibit MAO in the presence of kynuramine as a substrate was 4) from the aqueous soluble part (Figure 2). The physical and spectroscopic data agree with those reported, [24][25][26][27][28] and although compound 6 has been obtained by synthesis, 24 it is isolated for the first time as a natural product.…”

Disorder and the optical spectroscopy of Cr3+-doped glasses: I. Silicate glasses

“…Yang and Chen (1989) have discussed probable polymeric entities in silicate glasses; the compositions in table 1, which approximate those of Yang and Chen, have the polymericcontentsgiven in table2. Evidently, as the silicacontent increases, the amount of undamaged silica network and sheets or rings increase whereas that part of the silica which has reacted with aiitaii ions ciiangcs so that isolated 50:tetrahedra become less common.…”

Recent advances in the synthesis of natural products containing the phloroglucinol motif

“…Bioactive xanthone compounds have been widely found from Garcinia and Hypericum genera. 169,170 Among them, toxyloxanthone B ( 278 ) was isolated from Garcinia dulcis , 171 Hypericum sampsonii , 172 H. subalatum , 173 H. paturum , 174 H. perforatum , 175 and also from other sources like Maclura pomifera 176 and Cratoxylum formosum . 177 In 2014, Moody and co-workers described the total synthesis of toxyloxanthone B ( 278 ) (Scheme 50), utilizing regioselective nucleophilic addition of methyl salicylate 273 to benzyne intermediate generated from 274 , followed by attack of the resulting aryl anion to ester moiety, delivering the xanthone framework of 275 .…”