Fifteen coumarins, 2′‐angeloyl‐3′‐isovaleryl vaginate (4), archangelicin (3), oxypeucedanin hydrate (8), bergapten (5), byakangelicin angelate (15), imperatorin (11), isoimperatorin (6), isopimpinellin (13), 8‐[2‐(3‐methylbutroxy)‐3‐hydroxy‐3‐methylbutoxy]psoralen (12), osthol (1), ostruthol (9), oxypeucedanin (7), phellopterin (14), psoralen (2) and xanthotoxin (10), have been isolated from a chloroform extract of the roots of Angelica archangelica L. subsp. archangelica (Apiaceae). 2, 4, 12, and 15 are reported for the first time from A. archangelica L. The isolation was carried out using medium pressure liquid chromatography (MPLC) using the normal phase mode and then subsequently using a combination of the reversed and normal phase techniques. The eluents were optimized by thin layer chromatography and high performance liquid chromatography preassays according to the “PRISMA” system, and then transferred without modification of the solvent selectivity to preparative MPLC separations. The structures of the compounds were elucidated by a combination of spectroscopic methods. The isolation was carried out from a chloroform extract which in earlier tests had exhibited calcium blocking activity on the uptake of 45Ca2+ in clonal rat pituitary GH4C1 cells. The calcium antagonistic activity of the isolated compounds was then tested using the same method as for the extracts. All the coumarins tested exhibited calcium antagonistic activity. Archangelicin showed activity significantly higher than that of verapamil in this test system.
The aim of this study was to investigate whether hydroperoxides are formed in the autoxidation of conjugated linoleic acid (CLA) methyl ester both in the presence and absence of α-tocopherol. The existence of hydroperoxide protons was confirmed by D 2 O exchange and by chemoselective reduction of the hydroperoxide groups into hydroxyl groups using NaBH 4 . These experiments were followed by nuclear magnetic resonance (NMR) spectroscopy. The 13 C and 1 H NMR spectra of a mixture of 9-hydroperoxy-10-trans,12-cis-octadecadienoic acid methyl ester (9-OOH) and 13-hydroperoxy-9-cis,11-trans-octadecadienoic acid methyl ester (13-OOH), which are formed during the autoxidation of methyl linoleate, were studied in detail to allow the comparison between the two linoleate hydroperoxides and the CLA methyl ester hydroperoxides. The 13 C NMR spectra of samples enriched with one of the two linoleate hydroperoxide isomers were assigned using 2D NMR techniques, namely Correlated Spectroscopy (COSY), gradient Heteronuclear Multiple Bond Correlation (gHMBC), and gradient Heteronuclear Single Quantum Correlation (gHSQC). The 13 C and 1 H NMR experiments performed in this study show that hydroperoxides are formed during the autoxidation of CLA methyl ester both in the presence and absence of α-tocopherol and that the major isomers of CLA methyl ester hydroperoxides have a conjugated monohydroperoxydiene structure similar to that in linoleate hydroperoxides.
The aim of this study was to investigate whether hydroperoxides are formed in the autoxidation of conjugated linoleic acid (CLA) methyl ester both in the presence and absence of α-tocopherol. The existence of hydroperoxide protons was confirmed by D 2 O exchange and by chemoselective reduction of the hydroperoxide groups into hydroxyl groups using NaBH 4 . These experiments were followed by nuclear magnetic resonance (NMR) spectroscopy. The 13 C and 1 H NMR spectra of a mixture of 9-hydroperoxy-10-trans,12-cis-octadecadienoic acid methyl ester (9-OOH) and 13-hydroperoxy-9-cis,11-trans-octadecadienoic acid methyl ester (13-OOH), which are formed during the autoxidation of methyl linoleate, were studied in detail to allow the comparison between the two linoleate hydroperoxides and the CLA methyl ester hydroperoxides. The 13 C NMR spectra of samples enriched with one of the two linoleate hydroperoxide isomers were assigned using 2D NMR techniques, namely Correlated Spectroscopy (COSY), gradient Heteronuclear Multiple Bond Correlation (gHMBC), and gradient Heteronuclear Single Quantum Correlation (gHSQC). The 13 C and 1 H NMR experiments performed in this study show that hydroperoxides are formed during the autoxidation of CLA methyl ester both in the presence and absence of α-tocopherol and that the major isomers of CLA methyl ester hydroperoxides have a conjugated monohydroperoxydiene structure similar to that in linoleate hydroperoxides.
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