Bufadienolides and a New Lignan from the Bulbs of Urginea maritima.

Iizuka, Masaru; Warashina, Tsutomu; Noro, Tadataka

doi:10.1248/cpb.49.282

Cited by 66 publications

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“…25) Plant Material The roots of Asclepias syriaca L. (No. 2380M) were collected from the botanical garden of the University of Shizuoka in Japan in September, 1998 and identified by Prof. T. Noro.…”

Section: Methodsmentioning

confidence: 99%

Acylated-Oxypregnane Glycosides from the Roots of Asclepias syriaca

Warashina

Noro

2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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177Asclepias syriaca L. is a plant indigenous to North America and distributed widely. The monarch butterfly (Danaus plexippus L.) feeds on the Asclepias genus for protection from vertebrate predators. 1) Asclepias species are known to contain many kinds of cardenolides and their glycosides. 2-9)A. syriaca has also been reported to contain these compounds. [10][11][12] We have previously studied cardenolides and their glycosides.13) But, until now, there have been no reports about pregnane glycosides from A. syriaca. Pregnane glycosides are considered characteristic of Asclepias species.14-18) Accordingly, we started an investigation of pregnane glycosides and found twenty new 12-O-acylated-oxypregnane glycosides in the roots of A. syriaca. The present paper describes the isolation and structural determination of these new pregnane glycosides.A MeOH extract from the dried roots of A. syriaca was suspended in water. The suspension was extracted with diethyl ether and partitioned into an ether-soluble fraction, a water-soluble fraction and an ether-water emulsified fraction. The residues of these fractions were chromatographed on a silica gel column to give fractions of acylated-oxypregnane glycosides from which twenty new compounds were obtained along with seven known compounds. The structural determination of the known compounds 7, 10, 12, 13, 18, 23, and 27 was made based on comparisons of NMR spectral data with data in the literature. 16,17,19) In order to acquire the component aglycones and sugars, the fraction containing pregnane glycosides from the silica gel column chromatography was subjected to acid hydrolysis. The afforded aglycones were identified as ikemagenin (1a), 19,20) 5a,6-dihydroikemagenin (20a), 17) and 12-Otigloylisolineolon (21a), 17) in view of the 1 H-and 13 C-NMR spectral data.The acquired sugar mixtures were fractionated to cymarose, oleandrose, digitoxose, and canarose using silica gel column chromatography. The absolute configurations of these sugars were believed to be D-forms on the basis of the optical rotation values.Compound 1 was suggested to have the molecular formula Thus, 1 was glycosylated at the C-3 position, and was considered to be ikemagenin 3-O-diglycoside. Moreover, acid hydrolysis of 1 showed that the sugar moiety consisted of digitoxose and oleandrose, and these sugars were identified as b-D-digitoxopyranose and b-D-oleandropyranose, as judged from the J values of each anomeric proton signal (Jϭ9.5, 2.5 Hz). The sequence of the sugar moiety was determined from measurements of the rotating frame nuclear Overhauser effect (ROE) difference spectra irradiating at the anomeric proton of each sugar in 1. ROEs were found between Acylated-Oxypregnane Glycosides from the Roots of Asclepias syriacaTsutomu WARASHINA* and Tadataka NORO Institute for Environmental Sciences, University of Shizuoka; 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. Received October 29, 2008; accepted November 25, 2008; published online November 26, 2008 Twenty new pregnane glycosides were obtained...

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Section: Methodsmentioning

confidence: 99%

Acylated-Oxypregnane Glycosides from the Roots of Asclepias syriaca

Warashina

Noro

2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…The obtained known aglycones were identified as cynajapogenin A (1a), 1,2) glaucogenin-A (2a), 3,4) 2a-hydroxyanhydrohirundigenin (12a) 5) and atratogenin A (18a) 2) in view of the 1 H-and 13 C-NMR spectroscopic data. The acquired sugar mixtures were fractionated to cymarose, digitoxose and a mixture of oleandrose and sarmentose using silica gel column chromatography.…”

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“…In the 1 H-and 13 C-NMR spectra of 1, one anomeric proton and carbon signals were observed at d 5.45 (1H, dd, Jϭ9.5, 2.0 Hz)] and d 98.3, in addition to signals due to the aglycone, which was identified as a 13,14-seco-type pregnane, cynajapogenin A (1a) by acid hydrolysis with 0.1 M H 2 SO 4 . The 13 C-NMR spectral comparison of 1 with 1a showed that glycosylation shifts were presented at the C-2, -3 and -4 positions [C-2 (Ϫ2.2 ppm), C-3 (ϩ9.1 ppm), C-4 (Ϫ2.8 ppm)]. 6) Thus, 1 was glycosylated at the C-3 position, and was considered to be cynajapogenin A 3-O-monoglycoside.…”

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Glycosides of 14,15-Seco and 13,14:14,15-Disecopregnanes from the Roots of Cynanchum sublanceolatum

Warashina

Noro

2006

Chem. Pharm. Bull.

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Cynanchum sublanceolatum (MIQ.) MATUM. is an Asclepiadaceous plant and indigenous to the Honshu island of Japan. In the course of our research on phytochemicals, especially steroidal glycosides, in Asclepiadaceous plants, we have investigated the constituents of the roots of C. sublanceolatum. The paper describes the isolation and structural determination of thirty-two new pregnane glycosides along with three known compounds.The MeOH extract from the dried roots of C. sublamceolatum was suspended in water. The suspension was extracted with diethyl ether and partitioned into an ether-soluble fraction and a water-soluble fraction. The residue of each fraction was chromatographed on a silica gel column, respectively, to give a fraction of 14,15-seco and 13,14:14,15-disecopregnane glycosides from which thirty-two new compounds were obtained.In order to acquire the component aglycones and sugars, the fraction containing pregnane glycosides from a silica gel column chromatography was subjected to acid hydrolysis. The obtained known aglycones were identified as cynajapogenin A (1a), 1,2) glaucogenin-A (2a), 3,4) 2a-hydroxyanhydrohirundigenin (12a) 5) and atratogenin A (18a) 2) in view of the 1 H-and 13 C-NMR spectroscopic data. The acquired sugar mixtures were fractionated to cymarose, digitoxose and a mixture of oleandrose and sarmentose using silica gel column chromatography. The absolute configurations of digitoxose and cymarose were believed to be the D-form and a mixture of the D-and L-forms on the basis of their optical rotation values, respectively. The absolute configuration of glucose was determined to be the Dform based on GC analysis following its reaction with D-cysteine methyl ester hydrochloride (see Experimental).Compound 1 The following compounds 2-34 and 35 were also glycosylated at the C-3 position of each aglycone based on observation of glycosylation shifts in the 13 C-NMR spectra. HR-FAB-MS of compound 2 afforded a [MϩNa]ϩ peak at m/z 529.2413, suggesting the molecular formula, C 27 H 38 O 9 . Compound 2 was considered to be a 13,14:14,15-diseco-type pregnane monoglycoside, according to appearance of signals due to one anomeric proton and carbon signals together with those of glaucogenin-A (2a) in the 1 H-and 13 C-NMR spectra. Being subjected to acid hydrolysis with 0.1 M H 2 SO 4 , 2 afforded 2a and digitoxose. Thus, compound 2 was determined to be glaucogenin-A 3-O-b-D-digitoxopyranoside, and was named sublanceoside A 2 .The molecular formulae of compounds 3 and 4 were proposed to be C 33 H 48 O 10 and C 34 H 50 O 12 by HR-FAB-MS. The aglycone moieties of 3 and 4 were suggested to be 1a and 2a, respectively, on comparison of the 13 C-NMR spectroscopic data with those of 1 and 2, which were confirmed by being subjected to acid hydrolysis. Because of the consistency of the 1 H-and 13 C-NMR spectroscopic data of the sugar moieties in 3 and 4, both compounds were considered to possess the same sugar sequences. Furthermore, the presence of two anomeric proton and carbon signals at Thirty-two new 13...

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“…23) Extraction and Isolation The aerial part of Baccharis dracunculifolia DC. (644 g) was extracted three times with MeOH under reflux.…”

Section: Methodsmentioning

confidence: 99%

“…The molecular formulae of dracunculifosides G-I (23-25) were considered to be C 23 This data led us to conclude that the aglycone moiety of 24 was benzyl alcohol. This was confirmed by acid hydrolysis.…”

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