A new bioactive steroidal saponin from Agave attenuata

A new steroidal saponin was isolated from the leaves of Agave attenuata Salm-Dyck. Its structure was established as (3beta,5beta,22alpha,25S)-26-(beta-D-glucopyranosyloxy)-22-methoxyfurostan-3-yl O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside. The structural identification was performed using detailed analyses of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR and COLOC) and chemical conversions. The haemolytic potential of the steroidal saponin was evaluated and the anti-inflammatory activity was performed using the capillary permeability assay.     

A new bioactive steroidal saponin from Agave shrevei

A new steroidal saponin was isolated from the leaves of Agave shrevei Gentry. Its structure was established as 26-(beta-D-glucopyranosyloxy)-22-methoxy-3-(O-beta-D-glucopyranosyl-(1-->2)O-[O-beta-D-glucopyranosyl-(1-->4)-O-[O-beta-D-glucopyranosyl-(1-->6)]-O-beta-D-glucopyranosyl(1-->4)-beta-D-galactopyranosyl]oxy)-(3beta,5alpha,25R)-furostane. The structural identification was performed using detailed analyses of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR, and COLOC) and chemical conversions. The steroidal saponin showed absence of haemolytic effects in the in vitro assay, but demonstrated a significant inhibition of the capillary permeability activity.     

Structure elucidation by NMR spectroscopy of a new acetylated saponin from Centratherum anthelminticum

A new glycosylated triterpene has been isolated from the seeds of Centratherum anthelminticum, a medicinally important plant. The structural analysis of its acetylated derivative was performed by 1H, 13C NMR, 1H-1H COSY, HMQC, HMBC and DEPT spectroscopy. The saponin was shown to contain hederagenin and six sugar residues forming two glycosyl chains. The complete structure of the saponin was established as 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucuronopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucopyranosyl]-hederagenin.     

Two new triterpene saponins from the anti-inflammatory saponin fraction of Ilex pubescens root

The saponin fraction from the ethanolic extracts of the root of Ilex pubescens Hook. et Arn. (Ilexaceae) was found to exhibit potent anti-inflammatory effects on carrageenan-induced paw edema in rats. Two novel triterpene saponins, pubescenosides C and D (1 and 2, resp.), together with five known saponins were isolated from this saponin fraction. The structures of 1 and 2 were elucidated as (20beta)-3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-xylopyranosyl]ursa-12,18-dien-28-oic acid 28-O-beta-D-glucopyranosyl ester, and (20beta)-3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-xylopyranosyl]ursa- 12,18-dien-28-oic acid 28-O-beta-D-glucopyranosyl ester, respectively, on the basis of chemical and spectroscopic data. Five known saponins isolated from the saponin fraction were identified as ilexsaponin B(1), B(2), B(3), A(1), and chikusetsusaponin IV(a).     

Further saponins from Taverniera aegyptiaca

From the saponin fraction of the total methanolic extract of the dried root and stem barks of Taverniera aegyptiaca Boiss, six new triterpenoidal saponins of oleanane type were isolated and identified as 28-methyl serratagenate-3-beta-O-beta-xylopyranosyl (1-->2)-beta-glucopyranoside (2), 28-methyl serratagenate 3-beta-O-alpha-rhamnopyranosyl (1-->2)-beta-glucopyranoside (3), 3beta-O-alpha-rhamnopyranosyl (1-->2) beta-glucopyranosyl-olean-11,13(18)-dien-1beta, 3beta, 22beta-triol (4), 3beta-O-beta-glucopyranosyl (1-->2)-beta-glucuronopyranosylolean-11,13(18)-dien-1beta,3beta,22beta-triol (5), 3beta-O-beta-xylopyranosyl(1-->2)-beta-glucuronopyranosylolean-11,13(18)-dien-1beta,3beta,22beta-triol (6), 3beta-O-alpha-rhamnopyranosyl (1-->2)-beta-glucuronopyranosylolean-11,13(18)-dien-1beta, 3beta, 22beta-triol (7) together with the known oleanolic acid 3-beta-O-beta-glucoside (1). The identification of the isolated compounds was done on the basis of chemical and spectral evidences.     

In vivo anti-inflammatory activity of saponins from Bupleurum rotundifolium

Seven oleanane-type triterpene saponins were isolated from the methanolic extract of the aerial parts of Bupleurum rotundifolium. They were identified on the basis of their spectral data as 3-O-[alpha-L-rhamnopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl]-28-O-[beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl] echinocystic acid (saponin 1), 3-O-[alpha-L-rhamnopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->2)-beta-D-fucopyranosyl] 11-methoxy-primulagenin A (saponin 2), rotundioside E (saponin 3), rotundioside F (saponin 4), 3beta-sulfate, 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl] ester of primulagenin A (saponin 5), rotundioside C (saponin 6) and 3-O-[alpha-L-rhamnopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->2)-beta-D-fucopyranosyl] 11-methoxy-16beta,21alpha,28-trihydroxyolean-12-ene (saponin 7). All these saponins proved to be effective against TPA-induced ear edema in mice. Their ID50 were determined to be 248, 288, 128, 99 and 297 nmol/ear for saponin 1, 2, 3, 4 and 6, respectively. Saponins 3 and 6 were also active on a TPA multiple-dose model of skin chronic inflammation.     

A furostanol glycoside from rhizomes of Costus spicatus.

A new furostanol glycoside was isolated from the rhizomes of Costus spicatus. Its structure was established as (3 beta,22 alpha,25R)-26-(beta -D-glucopyranosyloxy)-22-methoxyfurost-5-en-3-yl O-D-apio-beta-D-furanosyl-(1-->2)-O-[6-deoxy-alpha-L-mannopyranosy l-(1-->4)]- beta-D-glucopyranoside. The structural identification was performed using detailed analysis of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR and COLOC) and chemical conversions.     

Triterpenoid saponins from Ardisia mamillata

Two saponins were isolated from the roots of Ardisia mamillata HANCE. Their structures were established on the basis of MALDI-TOFMS, 1H, 13C NMR and 2D NMR (COSY, HOHAHA, HETCOR, HMBC and ROESY) spectra, and on chemical evidence, to be ardisimamilloside A, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 2)]-alpha-L-arabinopyranosyl]-3beta, 16alpha,28alpha-trihydroxy-13beta,28-epoxy-oleanan+ ++-30-al; and ardisimamilloside B, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-( 1 --> 2)]-alpha-L-arabinopyranosyl]-beta3-hydroxy-13beta,28- epoxy-oleanan-16-oxo-30-al.     

A new steroidal saponin from AGAVE brittoniana and its biphasic effect on the Na+-ATPase activity

A new steroidal saponin, 3-{(O-6-deoxy-a-L-mannopyranosyl-(1 --> 4)-O-beta-D-glucopyranosyl-(1 --> 3)-O-[O-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl-(1 --> 2)]-O-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranosyl)oxy}-6-hydroxy-(3beta,5alpha,6alpha,25R)-spirostan-12-one, was isolated from Agave brittoniana Trel. The structure was determined by extensive NMR spectroscopy studies and chemical conversions. Its effects on the Na+-ATPase and (Na+ + K+)-ATPase activities of the proximal tubule from pig kidney were evaluated. It was observed that this steroidal saponin exerts a biphasic effect on the Na+-ATPase activity. It is concluded that the effect of the aqueous extract as a diuretic is due, at least in part, to the action of saponin on the ouabain-insensitive Na+-ATPase.     

A steroidal saponin from the seeds of Allium tuberosum.

A steroidal saponin, named tuberoside, together with seven known compounds, were isolated from the seeds of Allium tuberosum Rottl. ex Spreng. Its structure was established by spectroscopic data, hydrolysis, and comparison with spectral data of known compounds to be (2alpha, 3beta, 5alpha, 25S)-2,3,27-trihydroxyspirostane 3-O-alpha-L-rhamnopyranoyl-(1-->2)-O-[alpha-L-rhamnopyranoyl-(1-->4)]-beta-D-glucopyranoside.     

Haemolytic acylated triterpenoid saponins from Harpullia austro-caledonica

Eight new acylated triterpenoid saponins were isolated from the stem bark of Harpullia austro-caledonica along with the known harpuloside (9). Their structures were established using 1D and 2D NMR and mass spectrometry as 3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylbarringtogenol C (1), 3-O-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloyl barringtogenol C (2), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylbarringtogenol C (3), 3-O-alpha-L-arabinofuranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (4), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloyl protoaescigenin (5), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (6), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (7), 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (8). The EtOH extract of the stem bark showed in vitro cytotoxic activity against KB cells (90% at 10 microg/ml). At a concentration of 5 microg/ml, the saponin mixture showed haemolytic activity and caused 100% haemolysis of a 10% suspension of sheep erythrocytes.     

New steroidal saponins from rhizomes of Costus spiralis

Two new steroidal saponins were isolated from the rhizomes of Costus spiralis Rosc. Their structures were established as (3beta,25R)-26-(beta-D-glucopyranosyloxy)-22-hydroxyfurost-5-en-3-yl O-D-apio-beta-D-furanosyl-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside (1) and (3beta,25R)-26-(beta-D-glucopyranosyloxy)-22-hydroxyfurost-5-en-3-yl O-D-apio-beta-D-furanosyl-(1-->4)-O-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside (2). Their structural identifications were performed using detailed analyses of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques (DEPT, COSY, HETCOR and COLOC) and chemical conversions. The steroidal saponins were evaluated for anti-inflammatory activity.     

Steroidal glycosides from the underground parts of Helleborus caucasicus

Four polyhydroxylated and polyunsaturated furostanol glycosides (1-4), named caucasicosides A (1), B (2), C (3) and D (4), were isolated from the MeOH extract of the underground parts of Helleborus caucasicus, along with four spirostanol derivatives, a furostanol glycoside, a furospirostanol glycoside, 20-hydroxyecdysone and the bufadienolides hellebrigenin and deglucohellebrin. The structures of 1-4 were elucidated as furosta-5,20(22),25(27)-triene-1beta,3beta,11alpha,26-tetrol 26-O-beta-D-glucopyranoside (1), 26-O-beta-D-glucopyranosylfurosta-5,20(22),25(27)-triene-1beta,3beta,11alpha,26-tetrol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (2), 26-O-beta-d-glucopyranosyl-22alpha-methoxyfurosta-5,25(27)-diene-1beta,3beta,11alpha,26-tetrol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (3), 26-O-beta-D-glucopyranosylfurosta-5,20(22),25(27)-triene-1beta,3beta,26-triol 3-O-beta-D-xylopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-4-O-sulfo-alpha-L-arabinopyranoside (4). Structure elucidation was accomplished through the extensive use of 1D- and 2D NMR experiments including 1H-1H (COSY, 1D-TOCSY) and 1H-13C (HSQC, HMBC) spectroscopy along with ESI-MS and HR-ESI-MS. The aglycones of 1-4 have never been reported before.     

An aphid repellent glycoside from Solanum laxum

A spirostanic saponin was isolated from the ethanolic extract of the aerial parts of Solanum laxum Steud. The compound, named luciamin, was characterised by NMR spectroscopy, mass spectrometry and chemical methods, as (22R, 25S)-spirost-5-en-3 beta, 15 alpha-diol 3-O-[beta-D-glucopyranosyl (1 --> 2)-beta-D-glucopyranosyl-( 1 --> 4)-[alpha-L-rhamnopyranosyl-( 1 --> 2)]-beta-D-galactopyranoside]. The compound was tested against the aphid Schizaphis graminum by incorporation in artificial diets. It showed a deterrent (toxic) activity against the insect and is the first spirostane glycoside reported to have this activity.     

Balanitoside, a furostanol glycoside, and 6-methyldiosgenin from Balanites aegyptiaca.

In addition to a known spirostanol glycoside, balanitin-3, and a new sapogenol, 6-methyldiosgenin, a new furostanol saponin, balanitoside has been isolated from the fruits (mesocarp) of Balanites aegyptiaca. The structure of the glycoside has been determined as 26-O-beta-D-glucopyranosyl-3 beta, 22,26-trihydroxy-furost-5-ene 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-(1-->4)-beta-D-glucopyranoside, on the basis of spectroscopic and chemical evidence.     

Triterpenoid saponins from the stem bark of Caryocar villosum

Five triterpenoid saponins, caryocarosides II-22 (3), III-22 (4), II-23 (5), III-23 (6), and II-24 (7), have been isolated from the methanol extract of the stem bark of Caryocar villosum, along with two known saponins (1-2). The seven saponins are glucuronides of hederagenin (II) or bayogenin (III). Caryocaroside II-24 (7) is an unusual galloyl ester saponin acylated on the sugar chain attached to C-28, the 3-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-galactopyranosyl-(1-->3)-beta-D-glucuronopyranosyl hederagenin-28-O-[2-O-galloyl-beta-D-glucopyranosyl] ester. The structures of the saponins were established on the basis of extensive NMR ((13)C, (1)H, COSY, TOCSY, HSQC, HMBC and ROESY) and ESI-MS studies. The cytotoxic activity of saponins 2 and 3 was evaluated in vitro against human keratinocytes. The DOPA-oxidase inhibition and the lipolytic activities were evaluated ex vivo using an explant of human adipose tissue.     

New chlorogenin hexasaccharide isolated from Agave fourcroydes with cytotoxic and cell cycle inhibitory activities

A new chlorogenin hexasaccharide (1) was isolated from leaves of Agave fourcroydes (Agavaceae). The structure of the new saponin was elucidated as chlorogenin 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside] (1) by spectroscopic analysis and the result of acidic hydrolysis. The new saponin (1) as well as known hexasaccharides (3 and 5) isolated here showed cytotoxicity against HeLa cells, and 1 exhibited a cell cycle inhibitory effect at the G2/M stage at the concentration of 7.5 and 10 microg/mL.     

Synthesis and antitumor activity of icogenin and its analogue

Natural saponin icogenin, namely 25(S)-22-O-methyl-furost-5-en-3beta,26-dio-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside, and one of its analogues, 25(S)-22-O-methyl-furost-5-en-3beta,26-dio-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->3)]-alpha-D-glucopyranoside, were first synthesized via line strategy and convergent approach, respectively. It was observed that icogenin and its analogue show potent antitumor activity in vitro.     

A spirostanol saponin from the underground parts of Ruscus aculeatus

A new spirostanol saponin was isolated from the underground parts of Ruscus aculeatus and the structure was assigned as (23S,25R)-spirost-5-ene-3 beta,23-diol 23-O-[O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside] on the basis of spectroscopic analysis, including two-dimensional NMR spectroscopic techniques and the result of acid hydrolysis. The saponin is unique in structure having a diglycoside unit at C-23 of the spirostanol skeleton.     

Triterpenoid saponins from Fagonia cretica

Four new triterpenoid saponins were isolated and identified from the aerial parts of Fagonia cretica. They were characterized as 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] hederagenin 28-O-beta-D-glucopyranosyl ester, 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] oleanolic acid 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] 27-hydroxy oleanolic acid 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] ester and 3beta-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] olean-12-en-27-al-28-oic acid 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] ester. The structures of the saponins were assigned by spectral analyses (FABMS, 1H, 13C NMR, 1H-1H COSY, TOCSY, HMQC and HMBC spectra) and NOE experiments. To the best of our knowledge the genin 3beta hydroxy olean-12-en-27-al-28-oic acid is new.