风轮菜属植物皂苷成分研究进展

风轮菜属植物多为民间药用植物,皂苷类化合物为该属植物的主要活性成分,本文报道自1990年以来风轮菜属植物皂苷成分的研究进展。     

Molecular cloning and characterization of triterpene synthases from Medicago truncatula and Lotus japonicus

Cloning of OSCs required for triterpene synthesis from legume species that are amenable to molecular genetics will provide tools to address the importance of triterpenes and their derivatives during normal plant growth and development and also in interactions with symbionts and pathogens. Here we report the cloning and characterization of a total of three triterpene synthases from the legume species Medicago truncatula and Lotus japonicus. These include a -amyrin synthase from M. truncatula (MtAMYI) and a mixed function triterpene synthase from Lotus japonicus (LjAMY2). A partial cDNA predicted to encode a -amyrin synthase (LjAMY1) was also isolated from L. japonicus. The expression patterns of MtAMY1, LjAMY1 and LjAMY2 and of additional triterpene synthases previously characterised from M. truncatula and pea differ in different plant tissues and during nodulation, suggesting that these enzymes may have distinct roles in plant physiology and development.     

Kahiricosides II-V, cycloartane glycosides from an Egyptian collection of Astragalus kahiricus

Four cycloartane-type saponins, kahiricosides II-V (1-4), were isolated from the aerial parts of Astragalus kahiricus of Egyptian origin. Their structures were established as 9beta,19-cyclolanost-24E-ene-3beta,6alpha,16beta,27-tetraol-3-O-beta-D-glucopyranoside, 9beta,19-cyclolanost-24E-ene-3beta,6alpha,16beta,27-tetraol-3-O-(2'-O-acetyl)-beta-D-glucopyranoside, 9beta,19-cyclolanost-24E-ene-3beta,6alpha,16beta,27-tetraol-3-O-(6'-O-acetyl)-beta-D-glucopyranoside, and 9beta,19-cyclolanost-24E-ene-3beta,6alpha,16beta,27-tetraol-3-O-beta-D-glucopyranosyl-27-O-beta-D-glucopyranoside based on chemical and spectral evidences. All compounds exhibited very weak cytotoxicity against the A2780 ovarian cancer cell line.     

Transformations of Glycyrrhizic Acid: XV. Synthesis of Triterpene Saponins with Monosaccharide Residues Attached through Ester Bonds

Triterpene saponins, glycoside analogues of glycyrrhizic acid with a modified carbohydrate chain containing monosaccharide residues attached through ester bonds, were synthesized. To this end, peracetylated glycyrrhizic acid or its 30-methyl ester were glycosylated by 2,3,4,6-tetra-O-acetyl--D-gluco- or --D-galactopyranosyl bromide in dichloroethane in the presence of Ag₂CO₃. Glycerrhetinic acid saponin with D-Galp residues exhibited a higher antiulcer activity than glycyrrhizic acid in rats at a dose of 25 mg/kg.     

Bioactive steroidal alkaloid glycosides from Solanum aculeastrum.

Solanum aculeastrum Dunal was investigated for the presence of molluscicidal compounds. This led to the isolation of solaculine A, from the root bark in addition to known steroidal alkaloids; solamargine and beta-solamarine from the berries. The structures were elucidated by spectroscopic techniques. Molluscicidal activity of the aqueous extracts of the berries and root bark, and the isolated compounds were investigated.     

Triterpenoid saponins and acylated prosapogenins from Harpullia austro-caledonica

Three new triterpenoid saponins have been isolated from the stem bark of Harpullia austro-caledonica and identified as 24-O-[alpha-L-rhamnopyranosyl-(1->2)-beta-D-glucopyranosyl]-28-O-[beta-D-glucopyranosyl-(1->2)-beta-D-glucopyranosyl]-protoaescigenin, 24-O-[alpha-L-rhamnopyranosyl-(1->2)-beta-D-glucopyranosyl]-28-O-[beta-D-glucopyranosyl-(1->2)-beta-D-glucopyranosyl]-16-desoxyprotoaescigenin, 24-O-[alpha-L-rhamnopyranosyl-(1->2)-beta-D-glucopyranosyl]-28-O-[beta-D-glucopyranosyl-(1->2)-beta-D-glucopyranosyl]-24-oxo-camelliagenin D. The 21,22-di-O-angeloate esters of protoaescigenin and barringtogenol C were isolated in the acid hydrolysate of the saponin extract together with a new prosapogenin identified as 21beta,22alpha-di-O-angeloyl camelliagenin D. The structures were established using one- and two- dimensional NMR and mass spectrometry.     

Metabolic profiling of saponins in Medicago sativa and Medicago truncatula using HPLC coupled to an electrospray ion-trap mass spectrometer

Triterpene saponins isolated from Medicago sativa (alfalfa) and Medicago truncatula roots were separated, profiled and identified using an optimized, reversed-phase HPLC with on-line photodiode array detection and electrospray ionization mass spectrometry method (HPLC/PDA/ESI/MS). ESI source polarity and solvent conditions were compared. The effects of these parameters on mass spectral attributes were determined. Ion structures were confirmed using tandem mass spectrometry (MS/MS). Fifteen saponins were identified in alfalfa (cultivars Apollo, Radius, and Kleszczewska) based upon negative-ion HPLC/PDA/ESI/MS, HPLC/PDA/ESI/MS/MS and literature data. In addition, the identification of two new malonated saponins in alfalfa are proposed. Negative-ion HPLC/PDA/ESI/MS and HPLC/PDA/ESI/MS/MS spectra were utilized along with HPLC retention times to profile and identify 27 saponins in M. truncatula (cultivar Jemalong, A17). M. truncatula yielded a much more complex mixture of saponins than observed for alfalfa. The authors are not aware of any previous reports identifying saponin glycosides in M. truncatula.     

Noroleanane saponins from Celmisia petriei

Two biologically active noroleanane saponins from Celmisia petriei are identified as 3-O-(α-l-arabinopyranosyl (1 → 6)-β-d-glucopyranosyl (1 → 2)-α-l-arabinopyranosyl), 2β,17,23-trihydroxy-28-norolean-12-en-16-one and its 2″-O-acetyl derivative. ¹³C NMR and T₁ measurements allowed the determination of the sugar sequence and the majority of the linkage positions, but gave ambiguous results for the inner arabinose sugar. The structure of camellenodiol is revised to 3β,17-dihydroxy-28-norolean-12-en-16-one.     

Obtusilobinin and obtusilobin,two new triterpene saponins from Anemone obtusiloba

Obtusilobinin and obtusilobin, two new saponins, have been isolated from the ethanolic extract of Anemone obtusiloba (Ranunculaceae). The structural elucidation of obtusilobinin and obtusilobin have showed them to be olean-12-ene-28-oic-3-O-(α-l-arabinofuranosyl 1→2) (α-l-rhamnopyranosyl 1→4)-β-d-glucopyranoside and olean-12-ene-28-oic-3-O-α-l-rhamnopyranosyl 2→1-O-α-l-arabinofuranoside, respectively.     

Three New Steriodal Saponins from the Rhizomes of Tupistra chinensis Baker

The phytochemical constituent investigation on the 70 % ethanol extract of the rhizomes of Tupistra chinensis Baker resulted in the isolation of three new steroidal saponins which were named tuchinosides A–C ( 1 – 3 ). Their structures were determined by extensive spectrum analysis and chemical evidence, especially 2D NMR and HR-ESI-MS techniques. In addition, the cytotoxicity of compounds 1–3 against several human cancer cell lines was evaluated.