A new cytotoxic lanostane-type triterpene glycoside from the sea cucumber Holothuria impatiens

A new lanostane-type triterpene glycoside, impatienside A (1), was isolated from the sea cucumber Holothuria impatiens, together with a structurally related, known compound, bivittoside D (2). Their structures were elucidated by in-depth spectroscopic and mass-spectrometric methods, including (1)H-, (13)C-, and 2D-NMR, ESI-MS, and HR-ESI-MS experiments, as well as by chemical evidence. Compounds 1 and 2 possess the same hexasaccharide moieties, but differ slightly in their holostane-type triterpene aglycone. The two glycosides were found to exhibit in vitro cytotoxicities similar to or better than those of the potent anticancer drug etoposide (V-16) against seven different human tumor cells, with IC50 values of 0.37-2.75 microg/ml.     

Macrolactone glycosides of three lichen acids from Acarospora gobiensis, a lichen of Central Asia.

The compounds isolated from the extract of Central Asian lichen (Acarospora gobiensis H. Magn.) comprised three new glycosides having 18-hydroxy-dihydroalloprotolichesterinic, 18-hydroxy-neodihydroprotolichesterinic and 18-hydroxy-dihydroprotolichesterinic acids as aglycones and a di- or trisaccharide moiety linked at C-18 and at the carboxylic group. These compounds, called gobienines A-C, were found to be di- or trisacharides forming a macrolactone with the aglycone. The structures were elucidated by using extensive spectroscopic analysis (1D and 2D NMR, MS, IR and ORD) and chemical and enzymatic methods.     

Steroidal saponins from the aerial parts of Tribulus pentandrus Forssk

Seven new steroidal glycosides named pentandrosides A(1)-G(7) were isolated from the EtOH extract of the aerial parts of Tribulus pentandrus. Pentandrosides A(1)-E(5) possess cholestane aglycones, pentandroside F(6) a furostan-type aglycone and pentandroside G(7) an unusual acyloxypregnane aglycone probably derived from the degradation of a furostan skeleton. Structure elucidation of 1-7 was accomplished through the extensive use of 1D- and 2D NMR experiments including 1H-1H (DQF-COSY, 1D-TOCSY) and 1H-13C (HSQC, HMBC) spectroscopy along with ESIMS and HRESIMS.     

Glycosidic compounds of murolic, protoconstipatic and allo-murolic acids from lichens of Central Asia

Eleven compounds isolated from the extract of the Central Asian lichens comprised eight new glycosides having murolic, protoconstipatic and allo-murolic acids, as the aglycones and a saccharide moiety linked at C-18 made up of one or two sugars (glucose and apiose or rhamnose or xylose or arabinose). The structures were elucidated by using extensive spectroscopic analysis (1D and 2D NMR, MS, IR, UV and CD) and chemical methods.     

通光藤甙F,G,H和I结构

从通光藤(Marsdeniatenacissima)的茎中分离得到4个新的C21甾体甙———通光藤甙F(3),G(4),H(5)和I(6),以及2个已知化合物通光藤甙A(1)和B(2)。根据光谱数据和化学方法推定了其结构。同时,通过COLOC谱和二维核磁共振谱指定了这些化合物中甙元上11和12位的酯基确切连接位置。     

Glycoside esters from lichens of central Asia

Ten compounds isolated from the extract of the central Asian lichens comprised new glycosides and glycoside esters having 18R-hydroxy-dihydroalloprotolichesterinic, 18S-hydroxy-dihydroprotolichesterinic and 18S-hydroxy-neodihydroprotolichesterinic acids, as the aglycones and a saccharide moiety linked at C-18 and also at C-21 made by glucose, xylose or rhamnose. The structures were elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR, UV and ORD) and by biochemical methods.     

New pregnane glycosides from Stelmatocrypton khasianum

Four new pregnane glycosides, stelmatocryptonoside A, B, C, and D (1-4), were isolated from the stems of Stelmatocrypton khasianum. On the basis of chemical and spectral data, the structures of 1-4 were established as 3beta, 16alpha-dihydroxy-pregn-5-en-20-one-16-O-beta-D-glucopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside; 3beta, 20-dihydroxy-pregn-5-en-20-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->2)-beta-D-digitalopyranoside; 3beta, 16alpha-dihydroxy-pregn-5-en-20-one-16-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside; and 3beta, 16alpha-dihydroxy-pregn-5-en-20-one-16-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside. This is the first report of pregnane glycosides with sugar chains linked at C-16 of the aglycone.     

Three iridoid glycosides from Viburnum furcatum

Three new bitter iridoid glycosides having an 8,10,11-oxygen substituted iridoid skeleton with an isovaleryl moiety at C-1, have been isolated from the ether and ethyl acetate soluble fractions of the leaves of Viburnum furcatum. Two of them had a glucose moiety at C-11 of the iridoid skeleton and a p-coumaroyl group linked to C-6 of the sugar, and they were found to be geometrical isomers about the double bond of the p-coumaroyl2 moiety. The third one was characterized as a alloside of the same aglycone.     

Steroidal saponins from the tuber of Ophiopogon japonicus

Eight novel steroidal saponins, ophiopogonins H-O (1-8), along with seven known steroidal saponins (9-15) were isolated from the tubers of Ophiopogon japonicus. The structures of these new compounds were determined by detailed spectroscopic analysis, including extensive 1D and 2D NMR data, and the analysis of hydrolytic reaction products. For the first time, rare furostanol saponins with disaccharide moiety linked at position C-26 of the aglycone were reported to be isolated from a natural source.     

Two new polyhydroxylated steroidal glycosides from Paris polyphylla var. yunnanensis

Chemical investigation of Paris polyphylla smith var. yunnanensis afforded two new polyhydroxylated steroidal glycosides, named Parisyunnanosides K and L (1–2), together with nine known ones. The chemical structures of the new compounds were elucidated by 1D, 2D NMR and HR-ESI-MS techniques, together with chemical methods. Parisyunnanosides K and L (1–2) are rare C₂₇ steroidal glycosides with two double bonds located at C-5, 6 and C-25, 26 of the aglycone, respectively. The cytotoxic activities of the isolated compounds were evaluated against Caco-2 cells by CCK-8 assay. Among them, compounds 5–11 exhibited potent cytotoxic activity with IC₅₀ values ranging from 1.10 to 14.14 μM compared with the positive control oxaliplatin (1.38 μM).     

Four new immunomodulating steroidal glycosides from the stems of Stephanotis mucronata

Four new C-21 steroidal glycosides, mucronatosides E (1), F (2), G (3), and H (4), were isolated from the stems of Stephanotis mucronata. Two of them had the rare aglycone with a double bond between C-6 and C-7. Their structures were elucidated on the basis of spectroscopic data and chemical evidence. These isolated compounds were assayed for their immunological activities in vitro against concanavalin A (Con A)- and lipopolysaccharide (LPS)-induced proliferation of mice splenocytes. Compounds 2 and 4 showed immunosuppressive activities in a dose-dependent manner, while compounds 1 and 3 possessed immunoenhancing activities.     

nor-Oleanene type triterpene glycosides from the leaves of Acanthopanax japonicus

Three new (1-3) and two known (4-5) triterpene glycosides were isolated from the leaves of Acanthopanax japonicus (Araliaceae) and elucidated structurally by mass, 1D, and 2D NMR spectroscopy. All the compounds possessed a nor-oleanene triterpene skeleton as the aglycone. The structures of 1-5 were established as 28-O-alpha-L-rhamno-pyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester of 3beta-hydroxy- 30-nor-olean-12,20(29)-diene-23,28-dioic acid, designated as acanjaposide A, 3beta- hydroxy-23-oxo-30-nor-olean-12,20(29)-diene-28-oic acid, named acanjaposide B, 3beta,20alpha-dihydroxy-23-oxo-30-nor-olean-12-en-28-oic acid, named acanjaposide C, and nipponoside E, a known saponin, respectively.     

Two novel immunosuppressive pregnane glycosides from the roots of Stephanotis mucronata

Two novel pregnane glycosides, together with one new aglycone, were isolated from the roots of Stephanotis mucronata. Their structures were determined by means of chemical evidence and extensive spectroscopic methods including 1D and 2D NMR. The two pregnane glycosides displayed significant immunosuppressive activities in vitro.     

A trinorsesterterpene glycoside from the North American fern Woodwardia virginica (L.) Smith

A new trinorsesterterpene glycoside was isolated from the ethanol extract of the American fern Woodwardia virginica having a 3-[6-(4,8-dimethyl-nona-1,3,7-trienyl)-4-hydroxy-2,6-dimethyl-cyclohex-1-enyl]-3-hydroxypropionic acid, as the aglycone and a saccharide moiety linked at C-4 to glucoses, xylose or arabinofuranose. The structure was elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR and UV) including determination of absolute stereochemistry by means of the MTPA and PGME derivatives and also by chemical methods.     

Steroidal saponins from the fresh tubers of Ophiopogon japonicus

Eleven novel furostanol saponins, named ophiofurospisides C–E, G–N (1–3, 5–12), one new spirostanol saponin, named ophiopogonin R (13), were isolated from the fresh tubers of Ophiopogon japonicus. Their structures were determined on the basis of spectroscopic techniques (1D and 2D NMR) and HRESIMS. The isolated furostanol saponins possessed two sugar chains located at C-3 and C-26, respectively. Six furostanol saponins (1, 5–9) with disaccharide moiety linked at position C-26 of the aglycone were rare in the plant kingdom.     

Further glucosides of lichens' acids from Central Asian lichens

Eight compounds isolated from an extract of Central Asian lichens comprised new glucosides having murolic, protoconstipatic and allo-murolic acids as the aglycones and a saccharide moiety linked at C-18 made up of four glucoses. The structures were elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR, UV and CD) and by chemical methods.     

New neuritogenic steroidal saponin from Ophiopogon japonicus (Thunb.) Ker-Gawl

A new steroidal saponin was isolated from Ophiopogon japonicus. This saponin possesses a modification by 2-hydroxy-3-methylvalerylation of the hydroxyl group at C-4' of the sugar, linked to C-1 of the aglycone. It exhibited significant neuritogenic activity for PC12 cells. The structure-activity relationship revealed the aglycone, rather than the sugar moieties and acylation, to be important for the neuritogenic activity.     

Iridoid allosides from Viburnum opulus

Arbutin and four novel iridoid glycoside esters, named opulus iridoids I–IV, have been isolated from foliage of Viburnum opulus (Caprifoliaceae). Each opulus iridoid constitutes an inseparable mixture of two compounds, differing by containing either 2-methyl- or 3-methylbutyric acid in ester linkage at the 1-OH-group in an iridoid glycoside. In all glycosides 2′,3′-di-O-acetyl-β-D-allopyranose is linked through a glycosidic bond to C-11 in the iridoid aglycone. The opulus iridoids differ by the degree of acetylation of the aglycone and by the attachment, in III and IV, of a β-D-xylopyranosyl group at C-4 of the allose moiety. The structures have been elucidated by ¹H and ¹³C-NMR spectroscopy and by cleavage of the glycosidic linkage with boron trifluoride etherate in acetic anhydride, yielding the acetates of the cyclized aglycone and of the appropriate mono- or disaccharide. This is the second report of an iridoid attached to a sugar other than glucose and the second time allose has been encountered in higher plants. The systematic position of Viburnum is briefly discussed.     

Ornithosaponins A-D, four new polyoxygenated steroidal glycosides from the bulbs of Ornithogalumthyrsoides

By analyzing the steroidal glycoside content of fresh bulbs of Ornithogalum thyrsoides (Liliaceae), we were able to isolate four new polyoxygenated steroidal glycosides, which we named ornithosaponins A-D (1-4). The structures of 1-4 were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic or alkaline hydrolysis. The aglycone structure of 1-4 has not been previously reported. It is also notable that ornithosaponins B-D (2-4) have been found to contain 6-deoxy-beta-D-gulopyranose as a sugar component, which is rarely encountered in plant glycosides.     

Saponins from the roots of Zygophyllum gaetulum and their effects on electrically-stimulated guinea-pig ileum

A new ursanolide, 3beta-O-alpha-L-rhamnopyranosyl-(1->2)-O-alpha-L-arabinopyranosyl-(1->2)-beta-D-glucopyranosyl)oxy]-ursan-20beta,28-olide, zygophyloside N (1), and three known quinovic acid glycosides were isolated from the methanolic extract of the roots of Zygophyllum gaetulum. The crude extract, some fractions and 3-O-beta-D-glucopyranosyl quinovic acid 28-beta-D-glucopyranosyl ester, significantly and dose-dependently, are able to reduce the electrically-induced contractions of isolated guinea-pig ileum. The structure of compound (1) was determined, using 1D and 2D NMR techniques.