Steroidal saponins from the fruits of Asparagus racemosus

Three steroidal saponins, racemosides A (1), B (2) and C (3), were isolated from the methanolic extract of the fruits of Asparagus racemosus, and characterized as (25S)-5beta-spirostan-3beta-ol-3-O-{beta-D- glucopyranosyl (1-->6)-[alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->4)]-beta-D-glucopyranoside}, (25S)-5beta-spirostan-3beta-ol-3-O-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranoside and (25S)-5beta-spirostan-3beta-ol-3-O-{alpha-L-rhamnopyranosyl-(1-->6)-[alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside}, respectively, by spectrometric analysis and some chemical strategies.     

Studies on the Steroidal Saponins of Dioscorea tokoro Makino Collected from Zhejiang

Six steroidal saponins were isolated from rhizome of Dioscorea tokoro Makino (collected from Zhejiang). By means of acetylation, acid hydrolysis, IR, MS, and 13C-NMR etc., five of them were identical with yononin (A) (yield 0.0069%), dioscin (C) (0.04%), gracillin (D) (0.03%), protodioscin (E) (0.5%), protogracillin (F) (0.2%), respectively. Because of low yield, saponin B was not identified.     

Steroidal saponins from the rhizomes of Smilax menispermoidea.

Four steroidal saponins were isolated from the dried rhizomes of Smilax menispermoidea. One of them is new and its structure was established as (25S)spirost-5-en-3 beta,17 alpha-triol-3-O-[alpha-L-rhamnopyranosyl(1----2)] [alhpa-L-rhamnopyranosyl(1----4)]-beta-D-glucopyranoside using spectrometry and chemical methods, as well as comparison with three known steroidal saponins, dioscin, methyl protodioscin and pseudoprotodioscin.     

浙江山萆薢甾体皂甙的研究

从山萆薢根茎分到6个甾体皂甙,通过乙酰化、酸水解,红外、质谱和碳谱等鉴定,分别为约诺皂甙(A),薯蓣皂甙(C),纤细皂甙(D),原薯蓣皂甙(E),原纤细皂甙(F);皂甙 B 因得率极低,未能完成鉴定。     

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.     

The synthesis of gracillin and dioscin: two typical representatives of spirostanol glycosides

Two representative spirostanol saponins that have the typical structure for the sugar moiety, diosgenyl alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside (gracillin) and diosgenyl alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside (dioscin), were easily synthesized by a general approach. A procedure using guanidine for the selective deblocking of acetyl while retaining benzoyl protecting groups is described.     

Saponins in Tribulus terrestris – Chemistry and Bioactivity

Tribulus terrestris is a valuable herb known for its application in the folk medicine in many parts of the world. Furostanol and spirostanol saponins of tigogenin, neotigogenin, gitogenin, neogitogenin, hecogenin, neohecogenin, diosgenin, chlorogenin, ruscogenin and sarsasapogenin type are frequently found in this plant. Four sulphated saponins of tigogenin and diosgenin type are also isolated. Extracts and steroidal saponins have been found to possess various pharmacological activities. Preparations based on the saponin fraction of T. terrestris are used for treatment of infertility and libido disorders in men and women, as well as for treatment of cardiac diseases. Food supplements containing T. terrestris extracts are on sale in USA and Europe with claim of a general stimulating action. In this review the steroidal saponins found in T. terrestris are presented, covering the literature up to 2004. The data reveal clear difference in the saponin composition of samples from this plant species collected from different geographical regions. A comprehensive account on the biological activity of extracts and individual saponins is also included.     

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.     

Protective effects of steroid saponins from Paris polyphylla var. yunnanensis on ethanol- or indomethacin-induced gastric mucosal lesions in rats: structural requirement for activity and mode of action

The methanolic extract from the rhizomes of Paris polyphylla SM. var. yunnanensis (FR.) H-M. was found to potently inhibit ethanol-induced gastric lesions in rats. Through bioassay-guided separation, four known spirostanol-type steroid saponins, pennogenin 3-O-alpha-L-rhamnopyranosyl(1-->2)-[alpha-L-arabinofuranosyl(1-->4)]-beta-D-glucopyranoside (1), pennogenin 3-O-alpha-L-rhamnopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->4)-[alpha-L-rhamnopyranosyl(1-->2)]-beta-D-glucopyranoside (2), diosgenin 3-O-alpha-L-rhamnopyranosyl(1-->2)-[alpha-L-arabinofuranosyl(1-->4)]-beta-D-glucopyranoside (3), and diosgenin 3-O-alpha-L-rhamnopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->4)-[alpha-L-rhamnopyranosyl(1-->2)]-beta-D-glucopyranoside (4), and a new furostanol-type steroid saponin, parisaponin I (5), together with two known furostanol-type steroid saponins, trigofoenoside A (6) and protogracillin (7), were isolated from the active fraction. Compounds 1-4 (1.25-10 mg/kg, po) strongly inhibited gastric lesions induced by ethanol and indomethacin. With regard to structural requirement of steroid saponins, the 3-O-glycoside moiety and spirostanol structure were found to be essential for the activity and the 17-hydroxyl group in the aglycon part enhanced the protective effects against ethanol-induced gastric lesions. The protective effects of 1 and 3 against ethanol-induced gastric lesions were attenuated by pretreatment with indomethacin and N-ethylmaleimide. Compounds 1 and 3 weakly inhibited acid secretions in pylorus-ligated rats. These findings suggested that endogenous prostaglandins and sulfhydryl compounds were involved in the protective activity.     

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.     

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.     

Steroidal and phenolic constituents of Lilium speciosum.

Phytochemical examination of the fresh bulbs of Lilium speciosum forma vestale has led to the isolation of a new phenolic glycoside and a new steroidal saponin. The respective structures of the new compounds have been shown by spectral analysis to be 6'-O-feruloylsucrose and (25R,26R)-26-methoxyspirost-5-en-3 beta-o1 3-O-alpha-L-rhamnopyranosyl-(1----2)-beta-D-glucopyranoside. Several known phenolic glycosides and saponins have also been isolated and identified.     

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).     

Spirostanic diosgenin precursors from Dioscorea composita tubers

The main saponin from the fresh tuber of Dioscorea composita was dioscin and from the fermented material 3-O-[α-l-rhamnopyranosyl(1→4)-β-d-glucopyranosyl]diosgenin. The ¹³C NMR chemical shifts of saponins were used in the determination of their structure. No free sapogenin was isolated from the fresh tuber.     

Triterpenoid saponins from the fruits and galls of Sapindus mukorossi

Six saponins, sapinmusaponin K (1) [hederagenin-3-O-(3-O-acetyl-alpha-L-arabinopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], sapinmusaponin L (2) [hederagenin-3-O-(4-O-acetyl-alpha-L-arabinopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabino-pyranoside], sapinmusaponin M (3) [hederagenin-3-O-(2,3-O-diacetyl-beta-D-xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], sapinmusaponin N (4) [hederagenin-3-O-(2,4-O-diacetyl-beta-D-xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], sapinmusaponin O (5) [3,7,20(S)-trihydroxydammar-24-ene-3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside], and sapinmusaponin P (6) [3,7,20(R)-trihydroxydammar-24-ene-3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-d-glucopyranoside], along with seven known saponins (7-13), were isolated from fruits and the galls of Sapindus mukorossi. Their structures were elucidated by 1D and 2D NMR spectroscopic techniques and acid hydrolysis. Biological evaluation indicated that saponins 1-4 and 7-13 showed moderate cytotoxicity against several human tumor cell lines.     

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.     

Structural analogues of diosgenyl saponins: Synthesis and anticancer activity

Saponins display various biological activities including anti-tumor activity. Recently intensive research has been focused on developing saponins for tumor therapies. The diosgenyl saponin dioscin is one of the most common steroidal saponins and exhibits potent anticancer activity in several human cancer cells through apoptosis-inducing pathways. In this paper, we describe the synthesis of several diosgenyl saponin analogues containing either a 2-amino-2-deoxy-β-d-glucopyranosyl residue or an α-l-rhamnopyranosyl-(1→4)-2-amino-2-deoxy-β-d-glucopyranosyl residue with different acyl substituents on the amino group. The cytotoxic activity of these compounds was evaluated in MCF-7 breast cancer cells and HeLa cervical cancer cells. Structure–activity relationship studies show that the disaccharide saponin analogues are in general less active than their corresponding monosaccharide analogues. The incorporation of an aromatic nitro functionality into these saponin analogues does not exhibit significant effect on their cytotoxic activity.     

Syntheses of chlorogenin 6alpha-O-acyl-3-O-beta-chacotriosides and their antitumor activities

Chlorogenin 3-O-beta-chacotrioside (1) and its 6alpha-O-acyl derivatives (2-6) were concisely synthesized. Introduction of a hydroxyl or acyloxy group onto the C-6 of the steroidal aglycone of dioscin decreased significantly the cytotoxicity of the parent saponin (dioscin).     

Steroidal saponins from the bulbs of Camassia cusickii.

Six new steroidal saponins have been isolated from the fresh bulbs of Camassia cusickii. Their structures were determined by spectroscopic analysis and some chemical transformations to be (25R)-5 alpha-spirostan-3 beta,6 alpha-diol (chlorogenin) 6-O-beta-D-glucopyranoside, chlorogenin 6-O-beta-D-glucopyranosyl-(1----2)-beta-D-glucopyranoside, chlorogenin 6-O-beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranoside, chlorogenin 6-O-beta-D-glucopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----3)]-beta- D-glucopyranoside, (25R)-6 alpha-hydroxy-5 alpha-spirostan-3-one 6-O-beta-D-glucopyranosyl- (1----3)-beta-D-glucopyranoside and (25R)-3,3-dimethoxy-5 alpha-spirostan-6 alpha-ol 6-O-beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranoside. The saponins isolated were shown to contribute to the bitter taste of the bulbs.     

Liquid chromatography tandem mass spectrometry in study of the pharmacokinetics of six steroidal saponins in rats

A rapid, simple and sensitive high-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous determination of six main steroidal saponins in Paris polyphylla in rat plasma. Ginsenoside Rg3 was selected as the internal standard (IS). Plasma samples were pretreated with protein precipitation, and the separation was achieved on a reverse phase Agilent poroshell120 EC-C18 column using a gradient mobile phase system of acetonitrile–water containing 0.1% formic acid. The triple quadruple mass spectrometer was set in negative electrospray ionization mode and multiple reaction monitoring (MRM) was used for six steroidal saponins quantification. The precursors to produce ion transitions monitored for polyphyllin I, polyphyllin II, polyphyllin VI, polyphyllin VII, dioscin, gracillin and IS were m/z 899.5 > 853.4, 1059.5 > 1013.5, 783.4 > 737.4, 1075.5 > 1029.5, 913.5 > 867.4, 929.5 > 883.4 and 819.5 > 783.4, respectively. The intra- and inter-day precisions (RSD%) were less than 13% and the average extraction recoveries ranged from 85% to 97.0% for each analyte. Six steroidal saponins were proved to be stable during sample storage, preparation and analytical procedures. The established method was employed for simultaneous quantification and successfully used for the first time for the pharmacokinetics evaluation of the six main compounds after intragastric administration of P. polyphylla extract in Sprague–Dawley rats.