Xanthones and Xanthone O\textit{O}‐β\textit{β}‐D‐Glucosides from the Roots of Polygala azizsancarii\textit{Polygala azizsancarii} Dönmez

Nine xanthone derivatives (1–9) were isolated from the roots of Polygala azizsancarii, which is a narrow endemic species for the flora of Türkiye. Based on all of the evidence, the structures of 1–9 were established as two previously undescribed xanthone O-glucosides, 3-O-β-D-glucopyranosyloxy-1,6-dihydroxy-2,5,7-trimethoxyxanthone (1), 3-O-β-D-glucopyranosyloxy-1,6-dihydroxy-2,7-dimethoxyxanthone (2), and seven previously described xanthones, 1,3,6-trihydroxy-2,5,7-trimethoxyxanthone (3), 1,3,6-trihydroxy-2,7-dimethoxyxanthone (4), 1,2,3,4,7-pentamethoxyxanthone (5), 1,3-dihydroxy-2,5,6,7-tetramethoxyxanthone (6), 1,3-dihydroxy-4,7-dimethoxyxanthone (7), 1,7-dihydroxy-3-methoxyxanthone (8), and 1,7-dihydroxy-2,3-methylenedioxyxanthone (9). The structures of the compounds were determined by spectroscopic methods, including 1D-NMR (1H-NMR, 13C-NMR, DEPT-135), 2D-NMR (COSY, NOESY, HSQC, HMBC, INADEQUATE), and HR-MS. The solid-state structures of 1–4, including the absolute configurations of the stereogenic carbons of the sugar moiety in 1 and 2, were established by X-ray crystal-structure analyses. For the newly described compounds, the trivial names sancarosides A (1) and B (2) are proposed

Ecdysteroids from the underground parts of Rhaponticum acaule (L.) DC

In addition to two known ecdysteroids, 20-hydroxyecdysone and turkesterone, three previously undescribed stigmastane-type ecdysteroids were isolated from the underground parts of Rhaponticum acaule (L.) DC. by chromatographic techniques (CC, VLC, MPLC). The structures of the compounds were established by chemical (acetylation) and spectroscopic methods including UV, IR, HRMS, 1D-NMR: 1H-NMR, 13C-NMR, DEPT-135. and 2D-NMR: COSY, NOESY, HSQC, HMBC. Two compounds were isolated as an isomeric mixture and each of them was purified and converted to the corresponding acetylated derivative. Based on all of the evidence, the structures of three undescribed stigmastane-type ecdysteroids were established as 2β,3β,11α,20β,22α,24,28-heptahydroxy-6-oxo-stigmast-7-en-25,29-lactone and the cyclic 22,29-hemiacetals 22R and 22S stigmast-7-en-29-al,2β,3β,11α,20α,22,28-hexahydroxy-6-oxo, and the trivial names acaulesterone and rhapocasterones A and B are suggested, respectively. The structures and absolute configurations of 20-hydroxyecdysone and cyclic-22,29-hemiacetal-22R-stigmast-7-en-29-al,2β,3β,11α,20α,22,28-hexahydroxy-6-oxo were confirmed by X-ray crystal-structure analyses of their acetyl derivatives

In vitro effects of compounds isolated from Sideritis brevibracteata on bovine kidney cortex glutathione reductase

Glutathione reductase (GR, E.C 1.6.4.2) is a flavoprotein that catalyzes NADPH-dependent reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH). The aim of this study was to investigate in vitro effects of phenolic compounds isolated from Sideritis brevibracteata on bovine kidney GR. The Sideritis species are widely found in nature and commonly used as medicinal plants. 7-O-glycosides of 8-OH-flavones (hypolaetin, isoscutellarein and 3'-hydroxy-4'-O-methylisoscutellarein) were isolated from aerial parts of Sideritis brevibracteata. These compounds inhibited bovine kidney cortex GR in a concentration-dependent manner. Kinetic characterization of the inhibition was also performed