Complete (1)H and (13)C assignments of the four major saponins from Dioscorea villosa (wild yam)

Complete (1)H and (13)C spectral assignments for the four major steroidal saponins isolated by methanolic extraction of the roots of Dioscorea villosa, collected in North Carolina, United States (in summer and autumn), are presented in this paper. The structures were determined by a combination of (1)H, (13)C and 2D NMR techniques and were found to be ((3beta,25R)-26-(beta-D-glucopyranosyloxy)-22-methoxyfurost-5-en-3-yl-O-beta-D-glucopyranosyl-(1 --> 3)-O-beta-D-glucopyranosyl-(1 --> 4)-O-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (1) (or methyl parvifloside), ((3beta,25R)-26-(beta-D-glucopyranosyloxy)-22 methoxyfurost-5-en-3-yl-O-alpha-L-rhamnopyranosyl-(1 --> 2)-O-[beta-D-gluco- pyranosyl-(1 --> 4)]-beta-D-glucopyranoside (2) (or methyl protodeltonin), (3beta,25R)-spirost-5-en-3-yl-O-beta-D-glucopy ranosyl-(1 --> 3)-O-beta-D-glucopyranosyl-(1 --> 4)-O-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (3) (or Zingiberensis saponin I) and (3beta,25R)-spirost-5-en-3-yl-O-alpha-L-rhamnopyranosyl-(1 --> 2)-O-[beta-Ds-glucopyranosyl -(1 --> 4)]-beta-D-glucopyranoside (4) (or deltonin).     

Steroidal glycoalkaloids from the berries of Solanum distichum

Two steroidal glycoalkaloids, Solanidine 3-O-[alpha-L-rhamnopyranosyl-(1' --> 4)-[alpha-L-rhamnopyranosyl-(1' --> 2)]-beta-D-glucopyranoside] (1) and Solanidine 3-O-[alpha-L-rhamnopyranosyl-(1' --> 4)-beta-D-glucopyranoside] (2) commonly known as alpha-chanonine and beta 2-chanonine, were isolated from the berries of Solanum distichum. The structures of the isolated compounds were studied by 1D and 2D NMR techniques and FAB MS analysis. The 13C NMR signal assignments and direct elucidation of the glycoside linkages were established. Glycoalkaloids level in the dried berries, determined by a simple colorimetric method, was found to be 5.08 +/- 0.18 g%.     

Cytotoxic triterpenoid saponins from the roots of Cephalaria gigantea

Three new oleanane-type saponins, giganteosides L (1), M (2) and N (3) along with eight known ones were isolated from the roots of Cephalaria gigantea. Their structures were established as 3-O-[beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]-oleanolic acid, 3-O-[beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]-hederagenin, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]-hederagenin, respectively, by means of spectroscopic methods (1D and 2D NMR, HR-ESI-MS). Cytotoxic activity of monodesmosides was investigated in vitro using three cancer cell lines, namely, human non pigmented melanoma MEL-5 and human leukemia HL-60. Giganteosides D (4) and E (5) showed antiproliferative effect on human cell lines with IC(50) values in the range 3.15-7.5 microM.     

Three new steroidal saponins from the rhizome of Paris polyphylla

A mixture of a pair of stereoisomeric new spirostanol saponins (1a and 1b) and a new cholestane saponin (2) were isolated from the rhizome of Paris pollyphylla Smith var. yunnanensis. Their structures were elucidated as (25R)-spirost-5-en-3beta, 7beta-diol-3-O-alpha-L-arabinofuranosyl-(1 --> 4)-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (1a), (25R)-spirost-5-en-3beta, 7alpha-diol-3-O-alpha-L-arabinofuranosyl-(1 --> 4)-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (1b) and 26-O-beta-D-glucopyranosyl-(25R)-Delta(5(6), 17(20))-dien-16, 22-dione-cholestan-3beta, 26-diol-3-O-alpha-L-arabinofuranosyl-(1 --> 4)-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (2) by a combination of HR-ESI-MS, FAB-MS, 1D and 2D NMR techniques (including (1)H-NMR, (13)C-NMR, (1)H--(1)H COSY, HSQC, HMBC and NOESY).     

New phenylethanoid glycosides from Veronica pectinata var. glandulosa and their free radical scavenging activities

A known phenylethanoid glycoside, ehrenoside (1), was isolated together with three new phenylethanoid glycosides, verpectoside A (2), B (3) and C (4) from the aerial parts of Veronica pectinata var. glandulosa. On the basis of spectral analysis (UV, FAB-MS, 1H-, 13C- and 2D-NMR), compounds 2-4 were determined to be 2-(3,4-dihydroxyphenyl)ethyl-O-alpha-L-arabinopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->3)]-(4-O-trans-feruloyl)-beta-D-glucopyranoside, 2-(3,4-dihydroxyphenyl)ethyl-O-beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->3)]-(4-O-trans-caffeoyl)-beta-D-glucopyranoside and 2-(3,4-dihydroxyphenyl)ethyl-O-beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->3)]-(4-O-trans-feruloyl)-beta-D-glucopyranoside, respectively. Isolated phenylethanoid glycosides exhibited potent radical scavenging activity against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical.     

New terpenoids from Stachys parviflora Benth

Two new triterpenoidal saponins were isolated from the n-butanolic extract of Stachys parviflora (Lamiaceae). Their structures were elucidated on the basis of spectral data as stachyssaponin A; 3beta, 15alpha, 19alpha, 21beta, 22alpha-pentahydroxyolean-12-ene-28-oic acid 3-O-{alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-glucopyranoside}-22-O-{alpha-L-arabinofuranosyl-(1 --> 3)-beta-D-glucopyranoside} (1) and stachyssaponin B; 2beta, 3beta, 15alpha, 21beta-tetrahydroxyolean-12-ene-28-oic acid 2-O-[alpha-L-arabinofuranoside]-3, 21-bis-O-[beta-D-glucopyranoside] (2).     

Ardisimamillosides C-F, four new triterpenoid saponins from Ardisia mamillata

Four new triterpenoid saponins, ardisimamilloside C (1), 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->4)-[beta -D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl]-3beta,16al pha,28,30-tetrahydroxy-olean-12-en, ardisimamilloside D (2), 3-O-?alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->4)-[beta -D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl]-3beta,15al pha,28,30-tetrahydroxy-olean-12-en, ardisimamilloside E (3), 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->4)-[beta -D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosl]-13beta,2 8-epoxy-3beta,16alpha,29-oleananetriol, and ardisimamilloside F (4), 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->4)-[beta -D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl]-3beta,16al pha-dihydroxy-13beta,28-epoxy-oleanan-30-oic acid were isolated from the roots of Ardisia mamillata Hance. Structure assignments were established on the basis of highresolution (HR)-FAB-MS, 1H-, 13C-, and two-dimensional (2D)-NMR spectra, and on the chemical evidence.     

New phenolic glycosides from the seeds of Cucurbita moschata

Five new phenolic glycosides, cucurbitosides A-E (1-5), were isolated from the seeds of Cucurbita moschata. Their structures were elucidated as 2-(4-hydroxy)phenylethanol 4-O-(5-O-benzoyl)-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (1), 2-(4-hydroxyphenyl)ethanol 4-O-[5-O-(4-hydroxy)benzoyl]-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (2), 4-hydroxybenzyl alcohol 4-O-(5-O-benzoyl)-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (3), 4-hydroxybenzyl alcohol 4-O-[5-O-(4-hydroxy)benzoyl]-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (4) and 4-hydroxyphenyl 5-O-benzoyl-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (5) on the basis of spectroscopic analysis and chemical evidence.     

Total synthesis of methyl protodioscin: a potent agent with antitumor activity

Methyl protodioscin (1), otherwise known as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22-methoxy-25(R)-furost-5-ene-3 beta,26-diol, has been synthesized for the first time from diosgenin through nine steps in an overall yield of 7.8%.     

Ardisimamillosides G and H,two new triterpenoid saponins from Ardisia mamillata

Two new triterpenoid saponins, ardisimamilloside G (1), 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl]-13beta,28-epoxy-16-oxo-oleanan-3beta,30-diol and ardisimamilloside H (2), 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->4)-alpha-L-arabinopyranosyl]-3beta-hydroxy-13beta,28-epoxy-16-oxo-oleanan-30-al, were isolated from the roots of Ardisia mamillata HANCE. Structure assignments were established on the basis of spectral data and chemical evidence.     

Lupane glycosides from the leaves of Acanthopanax koreanum

Three new lupane-type saponins, acankoreosides F--H (1--3) were isolated from the methanol extract of the leaves of Acanthopanax koreanum NAKAI. The structures of these three saponins were established by chemical and spectroscopic analysis as 3alpha,30-dihydroxylup-20(29)-en-23,28-dioic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester (1), 3alpha,30-dihydroxylup-23-al-20(29)-en-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester (2), and (20S) 3alpha-hydroxylup-23-al-28,29-dioic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester (3), respectively. The effects of the isolates (1-3) on the lipopolysaccharide-induced production of nitric oxide and prostaglandin E2 were evaluated in RAW 264.7 macrophages.     

Studies on Balanites aegyptiaca fruits, an antidiabetic Egyptian folk medicine

An aqueous extract of mesocarps of the fruits of Balanites aegyptiaca exhibited a prominent antidiabetic activity by oral administration in streptozotocin induced diabetic mice. From one of the active fractions of this extract, two new steroidal saponins were isolated, and their structures were determined as 26-O-beta-D-glucopyranosyl-(25R)-furost-5-ene-3 beta,22,26-triol 3-O-[alpha-L-rhamnopyranosyl-(1----2)]-[beta-D-xylopyranosyl-(1---- 3)]-[alpha-L-rhamnopyranosyl-(1----4)]-beta-D-glucopyranoside and its 22-methyl ether. In addition, two known saponins, 26-O-beta-D-glucopyranosyl-(25R)-furost-5-ene-3 beta,22,26-triol 3-O-(2,4-di-O-alpha-L-rhamnopyranosyl)-beta-D-glucopyranoside and its methyl ether were isolated and identified. It was revealed that the individual saponins did not show antidiabetic activity, while the recombination of these saponins resulted in significant activity. From an ethanolic extract of the epicarps, two known flavonol glycosides, isorhamnetin-3-O-robinobioside and isorhamnetin-3-O-rutinoside were isolated and identified.     

Pregnane glycosides and steroid saponins from Smilax bockii Warb. and their NGF-potentiating activity

The chemical constituents of the roots of Smilax bockii Warb. were investigated and two pregnane glycosides and three steroid saponins were isolated. Their structures were established as 3beta-hydroxypregna-5,16-dien-20-one-3-O-alpha-L-rhamnopyranosyl(1 --> 4)-alpha-L-rhamnopyranosyl(1 --> 4)-[alpha-L-rhamnopyranosyl(1 --> 2)]-beta-D-glucopyranoside (1), 3beta-hydroxypregna-5,16-dien-20-one-3-O-alpha-L-rhamnopyranosyl(1 --> 2)-[alpha-L-rhamnopyranosyl(1 --> 4)]-beta-D-glucopyranoside (2), dioscin (3), methyl protodioscin (4), 26-O-beta-D-glucopyranosyl-22alpha-methoxyl-(25R)-furost-5-en-3beta, 26-diol 3-O-alpha-L-rhamnopyranosyl(1 --> 4)-alpha-L-rhamnopyranosyl(1 --> 4)-[alpha-L-rhamnopyranosyl(1 --> 2)]-beta-D-glucopyranoside (5) on the basis of spectral analysis and chemical methods. Compound 1 is a new natural product and compounds 2, 5 were first isolated from the genus Smilax. Compound 5 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells.     

Two new phenolic glycosides from Viscum articulatum

Two new phenolic glycosides, 1-O-benzyl-[5-O-benzoyl-beta-D-apiofuranosyl (1-->2)]-beta-D-glucopyranoside (1), and 4;-hydroxy-7,3;-dimethoxyflavan-5-O- beta-D-gluco-pyranoside (2), together with nine known flavanones 3 - 11, have been isolated from the dried whole plants of Viscum articulatum.Their structures were identified by extensive spectral analysis, especially 2D NMR techniques. Compound 9 showed weak anti-HIV-1 activity.     

Triterpene glycosides from the stems of Akebia quinata

The stems of Akebia quinata have been analyzed for their triterpene glycoside constituents, resulting in the isolation of six new triterpene glycosides, along with 19 known ones. On the basis of extensive spectroscopic analysis, including 2D NMR data, and chemical evidence, the structures of the new compounds were deter-mined to be 3beta-[(O-beta-D-glucuronopyranosyl-(1-->3)-alpha-L-arabinopyranosyl)oxy]olean-12-en-28-oic acid O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester, 3beta-[(O-beta-D-glucuronopyranosyl-(1-->3)-O-[alpha-L-rhamnopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl)oxy]olean-12-en-28-oic acid O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester, 3beta-[(O-beta-D-glucuronopyranosyl-(1-->3)-alpha-L-arabinopyranosyl)oxy]-23-hydroxyolean-12-en-28-oic acid O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester, 3beta-[(O-beta-D-glucuronopyranosyl-(1-->3)-O-[alpha-L-rhamnopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl)oxy]-23-hydroxyolean-12-en-28-oic acid O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester, 3beta-[(O-beta-D-glucopyranosyl-(1-->3)-O-[alpha-L-rhamnopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl)oxy]-29-hydroxyolean-12-en-28-oic acid, and 3beta-[(O-beta-D-glucopyranosyl-(1-->3)-O-[alpha-L-rhamnopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl)oxy]-23,29-dihydroxyolean-12-en-28-oic acid, respectively. The main triterpene glycosides contained in the stems of A. quinata were found to have two sugar units at C-3 and C-28 of the aglycone in this study, whereas those of Akebia trifoliate were reported to possess one sugar unit at C-28 of the aglycone. It may be possible to distinguish between A. quinata and A. trifoliate chemically by comparing their triterpene glycoside constituents.     

New furostanol saponins from Allium ascalonicum L

An analysis of the polar extracts from Allium ascalonicum L. led to the isolation of two new furostanol saponins (compound 1 and 2) and two known furostanol saponins (compound 3 and 4). On the basis of 1D and 2D NMR (including (1)H, (13)C NMR, (1)H--(1)H COSY, HSQC, TOCSY, HMBC, and NOESY), FAB-MS spectrometry, and chemical methods, their structures were elucidated as (25R)-26-O-beta-D-glucopyranosyl-22-hydroxy-5alpha-furost-2-one-3beta, 5, 6beta, 26-tetraol-3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (ascalonicoside C, 1), (25R)-26-O-beta-D-glucopyranosyl-22-methoxy-5alpha-furost-2-one-3beta, 5, 6beta, 26-tetraol- 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (ascalonicoside D, 2), (25R)-26-O-beta-D-glucopyranosyl-22-hydroxy-5-ene-furostan-3beta, 26-diol-3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside (dichotomin, 3), and (25R)-26-O-beta-D-glucopyranosyl-22-hydroxy-5-ene-furostan-3beta, 26-diol-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-arabinofuranosyl-(1-->4)]-beta-D- glucopyranoside (parisaponin I, 4).     

Steroidal oligoglycosides from the seeds of Allium tuberosum

Three new spirostanol steroidal oligoglycosides, together with a known oligoglycoside, were obtained from the seeds of Allium tuberosum after enzymatic hydrolysis of furostanol saponin fraction by beta-glucosidase. On the basis of spectroscopic analysis, the structure of new spirostanol oligoglycosides were elucidated as (25S)-spirost-5-ene-2alpha,3beta-diol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-be ta-D-glucopyranoside, (25S)-spirostane-3beta,5beta,6alpha-triol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside, and (25S)-5beta-spirostane-3beta,6alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside.     

Structure elucidation and complete NMR spectral assignments of two new dammarane-type tetraglycosides from Panax quinquefolium

Two new saponins were isolated from leaves of Panax quinquefolium and their structures were elucidated as 3beta, 12beta, 20S-trihydroxy-25-methoxydammar-23-ene 3-O-{[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[alpha-L-arabinopyranosyl(1-->6)]-beta-D-glucopyranoside (1) and 3beta, 20S-dihydroxy-12beta, 23R-epoxydammar-24-ene 3-O-{[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[beta-D-xylopyanosyl(1-->6)]-beta-D-glucopyranoside (2) on the basis of (1)D and (2)D NMR (including (1)H, (13)C-NMR, (1)H-(1)H COSY, HSQC, TOCSY, HMBC, and NOESY), ESI-MS spectrometry and chemical methods.