New steroidal saponins of Agave americana

Two new saponins, agavasaponin E and agavasaponin H have been isolated from the methanolic extract of Agave americana leaves and their structures elucidated. Agavasaponin E is 3-O-[β-d-xylopyranosyl-(1→2glc1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-α-d-galactopyranosyl]-(25R)-5α-spirostan-12-on-3β-ol, whereas agavasaponin H is 3-O-[β-d-xylopyranosyl-(1→2 glc 1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3 glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-β-d-galactopyranosyl]-26-O-[β-d-glucopyranosyl]-(25R)-5α-furostan-12-on-3β,22α,26-triol.     

Melongoside L and melongoside M,steroidal saponins from Solanum melongena seeds

Two new steroidal saponins, melongoside L and melongoside M, have been isolated from a methanolic extract of Solanum melongena seeds and their structures elucidated.     

Novel steroidal saponins from Dioscorea esculenta (Togedokoro)

Fifteen steroidal saponins 1–15, which include 4 furostanol glycosides 1–3 and 15, and 11 spirostanol glycosides 4–14, were isolated from the tubers and leaves of lesser yam (Dioscorea esculenta, Togedokoro). Their structures were identified by nuclear magnetic resonance and liquid chromatography mass spectroscopy. Four steroidal saponins 9, 11, 14, and 15 were found to be novel compounds.     

Steroidal saponins of Yucca filamentosa: Yuccoside C and protoyuccoside C

Two new saponins, yuccoside C and protoyuccoside C, have been isolated from the methanolic extract of Yucca filamentosa root and their structures elucidated. Yuccoside C is 3-O-[α-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, whereas protoyuccoside C is 3-O-[α-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosy]-(25S)-5β-furostan-3β,22α,26-triol.     

Steroidal saponins of Asparagus curillus

Three spirostanol and two furostanol glycosides were isolated from a methanol extract of the roots of Asparagus curillus and characterized as 3-O-[α-l-arabinopyranosyl (1→4)- β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-[{α-l-rhamnopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-(25S)-5β-spirostan- 3β-ol, 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β- d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]- 22α-methoxy-(25S)-5β-furostan-3β, 26-diol and 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]- (25S)-5β-furostan-3β, 22α, 26-triol respectively.     

Steroidal saponins of Asparagus adscendens

From the methanol extract of the fruits of Asparagus adscendens sitosterol-β-d-glucoside, two spirostanol glycosides (asparanin A and B) and two furostanol glycosides (asparoside A and B) were isolated and characterized as 3-O-[β-d-glucopyranosyl (1→2)-β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl}-(25S)-5β-spirostan-3β-ol,3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl|} -26-O-(β- d-glucopyranosyl)-22α-methoxy-(25S)-5β-furostan-3β,26-diol and 3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl}-26-O-(β-d-glucopyranosyl)- 25S)-5β-furostan-3β,22α, 26-triol, respectively.     

Melongosides n,o and p: steroidal saponins from seeds of solanum melongena

Three new saponins, melongosides N, O and P, have been isolated from the methanolic extract of seeds of Solanum melongena and their structures elucidated. Melongoside N is 3-O-[β-D-glucopyranosy l-(1 → 2)-β-D-glucopyranosyl]-26-O-(β-D-glucopyranosyl)-(25R)-5α-furostan-3β,22 α,26-triol, whereas melongoside O is 3-O-[β-D-glucopyranosyl-(1 → 2)β-D-glucopyranosyl]- 26-O-(β-D-glucopyranosyl)-(25R)-furost-5-en-3β,22α,26-triol and melongoside P is 3-O- [β-D-glucopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-β-D-glucopyranosyl)-26-O- (β-D-glucopyranosyl)-(25 R)-5α-furostan-3β,22α,26-triol.     

Spirostanol glycosides from Asparagus plumosus

Three spirostanol glycosides were isolated from a methanol extract of the leaves of Asparagus plumosus and characterized.     

Oligofurostanosides from Solanum nigrum

One spirostanol glycoside and two furostanol glycosides have been isolated from a methanol extract of the stems and roots of Solanum nigrum and ide     

Carbon-13 NMR spectroscopy of steroidal sapogenins and steroidal saponins

The ¹³C NMR chemical shifts of 130 naturally occurring steroidal sapogenins and saponin derivatives published up to 1983 are listed and a number of methods for signal assignment are explained. The utility of ¹³C NMR spectral analysis for the structure elucidation of these compounds is discussed.     

Steroidal alkaloid saponins and steroidal saponins from Solanum surattense

A rare 16β-H steroidal alkaloid saponin (1), an avenacoside-type saponin (2), two steroidal saponins (4, 5), one revised-structure steroidal saponin (3) and six known compounds (6-11) were isolated from aerial parts of Solanum surattense Burm. f. Their structures were established on the basis of physical data, as well as by using spectroscopic (HRESIMS, 1D and 2D NMR), and chemical analysis methods. Compounds 1 and 11 showed cytotoxicity against A549 cell line with IC₅₀ values of 20.3 and 15.7 μM, respectively.     

Atropurosides A-G, new steroidal saponins from Smilacina atropurpurea

Atropurosides A-G (1-7), seven new steroidal saponins, which possess new polyhydroxylated aglycones, were isolated from the rhizomes of Smilacina atropurpurea (Convallariaceae), together with a known saponin, dioscin (8). Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1D and 2D NMR techniques and chemical methods. Antifungal testing of the eight compounds indicated that atropurosides B (2) and F (6) were fungicidal against Candida albicans, Candida glabrata, Cryptococcus neoformans, and Aspergillus fumigatus with minimum fungicidal concentrations (MFCs) < or = 20 microg/ml, while dioscin (8) was selectively active against C. albicans and C. glabrata (MFC < or = 5.0 microg/ml). Furthermore, the antifungal saponins 2, 6, and 8 were evaluated for their in vitro cytotoxicities in a panel of human cancer cell lines (SK-MEL, KB, BT-549, SK-OV-3, and HepG2) and non-cancerous Vero cells. All showed moderate cytotoxicities. It appears that the antifungal activity of these steroidal saponins correlates with their cytotoxicity against mammalian cells.     

Cytotoxic steroidal saponins from Polygonatum punctatum

Four new steroidal saponins, polypunctosides A-D (1-4, resp.), were isolated from the rhizomes of Polygonatum punctatum, together with five known steroidal saponins. On the basis of chemical and spectral evidence, the structures of the new saponins were established as (3beta,23S,25R)-23-(alpha-L-arabinopyranosyloxy)spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (1), (3beta,23S,25R)-23-[(2-O-acetyl-alpha-L-arabinopyranosyl)oxy]spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (2), (3beta,23S,25R)-23-[(3-O-acetyl-alpha-L-arabinopyranosyl)oxy]spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (3), and (3beta,23S,25R)-23-[(4-O-acetyl-alpha-L-arabinopyranosyl)oxy]spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (4). The cytotoxic activity of the isolated saponins was evaluated towards HeLa cells.     

The co-occurrence of ecdysones with bufadienolides and steroidal saponins in the genus Helleborus

A method is described for the detection of ecdysones in small quantities of plant material. When applied to 14 taxa of Helleborus L., ecdysterone and 5 β-hydroxyecdysterone were detected and quantified in 11; the other 3, which are morphologically distinct, gave a negative result. The co-occurrence of ecdysones with bufadienolides and steroidal saponins is discussed. The isolation of the ecdysones from the aerial parts of H. orientalis hybrids is described.     

Cytotoxic steroidal saponins from Trillium kamtschaticum

Eight new steroidal saponins, trillikamtosides K–R (1–8), along with three known analogues, were isolated from the whole plants of Trillium kamtschaticum. Their structures were unambiguously established by interpretation of spectroscopic data (MS and NMR) and chemical methods. Compound 1 had a rare aglycone featuring a skeleton of 16-oxaandrost-5-en-3-ol-17-one, which was reported for the first time. The isolated saponins were tested for cytotoxicities against HCT116 cells, and trillikamtoside R (8) was found to show the most cytotoxic effect with an IC₅₀ value of 4.92 μM.     

Structural studies on some saponins from Lecaniodiscus cupanioides

Four triterpenoid saponins isolated from the stem bark of Lecaniodiscus cupanioides and denoted S-2,S-3,S-4 and S-5, were identified as follows. S-2:3-O-[α-l-arabinopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]-hederagenin; S-3:3-O-[α-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabino-pyranosyl ]-hederagenin; S-4:3-O- [α-l-arabinopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→ 2)-α-l-arabinopyranosyl]-hederagenin; S-5:3-O- [α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl ]-hederagenin. Of these, S-2 and S-4 are new substances.     

Modulation of sodium pumps by steroidal saponins

Costus spicatus, used in Brazilian traditional medicine to expel kidney stones, contains steroidal saponins with different chemical characteristics. In spite of its popular utilization as potent diuretic, no scientific reports correlate this activity with the chemical constituents of the extract. Therefore, two steroidal saponins (3 beta,22 alpha,25R)-26-(beta-D-glucopyranosyloxy)-2-methoxyfurost-5-en-3-yl O-D-apio-beta-D-furanosyl-(1-->2)-O-[6-deoxy-alpha-L-mannopyranosyl-(1-->4)]-beta-D-glucopyranoside (1) and (3 beta,22 alpha,25R)-spirostan-3-yl O-D-apio-beta-D-furanosyl-(1-->2)-O-[6-deoxy-alpha-L-mannopyranosyl-(1-->4)]-beta-D-glucopyranoside (1a), were isolated from the rhizomes of this plant and their effects on the Na+-ATPase and (Na+ + K+)-ATPase activities of the proximal tubule from pig kidney were evaluated. It was observed that 1 and 1a inhibit specifically the Na+-ATPase activity.     

Concise synthesis and antitumor activities of trisaccharide steroidal saponins

The naturally derived trisaccharide steroidal saponin 1 and structurally modified derivatives 2 and 3 bearing the same sarsasapogenin aglycon were synthesized concisely via a direct transglycosylation strategy. The antitumor activities of the synthetic trisaccharide saponins 1–3 and their corresponding α-isomers 1a–3a were preliminarily evaluated against human gastric adenocarcinoma cell (MKN-45) and human epithelial cervical cancer cell (HeLa) by CCK-8 assay.     

Nuatigenin-type steroidal saponins from Veronica fuhsii and V. muldtfida

A new nuatigenin-type steroidal saponin, multifidoside (2), was isolated from the aerial parts of Veronica fuhsii and V multifida and its structure was identified as 3-O-([alpha-L-rhamnopyranosyl-(1-->2glu)]-[beta-D-glucopyranosyl-(1-->4rha)-alpha-L-rhamnopyranosyl (1-->4glu)]-beta-D-glucopyranosyl]nuatigenin 26-O-beta-D-glucopyranoside. Additionally, a known steroidal saponoside, aculeatiside A (1), from V. fuhsii, a phenylethanoid glycoside, verpectoside A (3), and a flavon glycoside, isoscutellarein 7-O-(2"-O-6"-O-acetyl-beta-D-allopyranosyl-beta-D-glucopyranoside) (4) from V. multifida were isolated.     

Two new steroidal saponins from Dioscorea panthaica

Two new furostanol saponins, 3-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,22(23)-dien-3β,20α,26-triol (1), 3-O-[β-d-glucopyranosyl-(1→3)-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-20(R)-methoxyl-25(R)-furosta-5,22(23)-dien-3β,26-diol (2) were isolated from the Dioscorea panthaica along with five known steroidal saponins (3–7). The structures of the new saponins were determined by detailed analysis of spectral data (including 2D NMR spectroscopy). The inhibitory activities of the saponins against α-glucosidase were investigated, gracillin (4) and 3-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,20(22)-dien-3β,26-diol (5) were found to exhibit potent activities with IC₅₀ values of 0.11 ± 0.04 mM and 0.09 ± 0.01 mM.