Antibacterial activity of an eudesmane sesquiterpene isolated from common Varthemia, Varthemia iphionoides

Eudesmane and rearranged eudesmane sesquiterpenes from Nectandra cissiflora

“…Fraction G3-5 (116.2 mg) afforded an inseparable mixture (13.7 mg) of 5b-hydroxy-4-oxo-11(13)-dehydroiphionan-12-oic acid (5, major compound) 10 and 3a-hydroxyisoiphion-11(13)-en-12-oic acid (6) 11 after CC on silica gel 230-400 mesh using a gradient system of hexane→EtOAc→MeOH as eluents, followed by CC on Sephadex LH-20 (MeOH). Viscic acid (3, 15.0 mg) 12 and a mixture (25.0 mg) of 3 and 3-oxo-g-costic acid (4, major component) 13 were obtained from fraction G3-10 (95.9 mg) after RP-8 semipreparative HPLC (CH 3 , were in good agreement with those reported for costic acid, a eudesmane sesquiterpene which was previously isolated from a few members of the Lauraceae, as well as from other plant families . 4,7,8,14 The 1 H NMR spectrum of 1 was characterized by the presence of the C-14 methyl singlet at d 0.76, two singlets assigned to the hydrogens of the double bond conjugated to the carboxyl group at C-11 (13) and another two singlets attributed to the exocyclic olefinic hydrogens at C-15.…”

“…Viscic acid (3, 15.0 mg) 12 and a mixture (25.0 mg) of 3 and 3-oxo-g-costic acid (4, major component) 13 were obtained from fraction G3-10 (95.9 mg) after RP-8 semipreparative HPLC (CH 3 , were in good agreement with those reported for costic acid, a eudesmane sesquiterpene which was previously isolated from a few members of the Lauraceae, as well as from other plant families . 4,7,8,14 The 1 H NMR spectrum of 1 was characterized by the presence of the C-14 methyl singlet at d 0.76, two singlets assigned to the hydrogens of the double bond conjugated to the carboxyl group at C-11 (13) and another two singlets attributed to the exocyclic olefinic hydrogens at C-15. In the C NMR spectra of this mixture, the signals corresponding to compound 1 were readily discernible and the remaining ones, which were attributed to compound 2, indicated that their structures only differed in the position of the non-conjugated double bond, which was located at C-3 in the skeleton of the latter.…”

“…12 Unambiguous assignment of The unequivocal assignments of the remaining carbon resonances of 4 were based on the correlations observed in the HSQC and HMBC spectra. Therefore, compound 4 was identified as 3-oxo-4,11(13)-eudesmadien-12-oic acid, also known as 3-oxo-g-costic acid, which was previously characterized in Varthemia iphionoides 13 and also in other members of the Asteraceae. However, the previous chemical shift assignments reported for the carbon resonances C-1, C-8, C-9, C-14 and C-15 13 and C-1, C-2, C-6 and C-8 15 of 3-oxo-g-costic acid should be corrected and have thus been reassigned in the present work.…”

“…Herein we report the isolation of four eudesmane-and two rearranged eudesmanetype sesquiterpene acids from this plant, in addition to (-)-epicatechin. 1 H and 13 C 1D and 2D NMR spectra were recorded at 300 MHz ( 1 H) and 75 MHz ( 13 C) on a Bruker DPX-300 spectrometer. Standard pulse sequences were used for homo -and heteronuclear correlation experiments.…”

“…Fraction G3-5 (116.2 mg) afforded an inseparable mixture (13.7 mg) of 5b-hydroxy-4-oxo-11(13)-dehydroiphionan-12-oic acid (5, major compound) 10 and 3a-hydroxyisoiphion-11(13)-en-12-oic acid (6) 11 after CC on silica gel 230-400 mesh using a gradient system of hexane→EtOAc→MeOH as eluents, followed by CC on Sephadex LH-20 (MeOH). Viscic acid (3, 15.0 mg) 12 and a mixture (25.0 mg) of 3 and 3-oxo-g-costic acid (4, major component) 13 were obtained from fraction G3-10 (95.9 mg) after RP-8 semipreparative HPLC (CH 3 CN-H 2 O-AcOH 3.5:6.45:0.05). (-)-Epicatechin (7, 8.3 mg) was isolated from fraction N after CC on Sephadex LH-20 (MeOH) followed by CC on silica gel 230-400 mesh eluted with hexane, EtOAc and MeOH by gradually increasing the polarity gradient.…”