小花草玉梅化学成分研究

目的:研究银莲花属植物小花草玉梅的化学成分。方法:采用硅胶柱色谱,凝胶柱色谱,反相柱色谱并结合制备高效液相色谱等技术分离纯化单体化合物,并根据理化性质及光谱数据鉴定结构。结果:分离并鉴定了4个化合物,分别是常春藤皂苷元-28-O-β-D-吡喃葡萄糖酯苷(1)、3-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖-齐墩果酸皂苷元-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(2)、3-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖-常春藤皂苷元-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(3)和3-O-β-D-吡喃核糖-(1→3)-α-L-吡喃鼠李糖-(1→2)-α-L-吡喃阿拉伯糖-常春藤皂苷元-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(4)。结论:化合物1为首次从银莲花属植物中分离得到,2-4为首次从小花草玉梅中分离得到。     

Characterization of quillaja bark extracts and evaluation of their purity using liquid chromatography–high resolution mass spectrometry

In the course of development of semi-preparative liquid chromatographic methods for the isolation of individual quillaja saponins from Quillaja saponaria (L.), some commercially available quillaja bark extracts revealed a distinctive and characteristic pattern of additional peaks in the chromatogram that could not be attributed to saponins commonly present in quillaja. To identify these peaks, analytical procedures based on HPLC coupled with high resolution MS detection were optimized which allowed the identification of the additional saponins Mi saponin A, Mi saponin B, Mi saponin C, madhucoside A and madhucoside B. These compounds are known to be the main saponins of the Indian plant Madhuca longifolia (L.). Tandem MS experiments were performed for the unambiguous assignment of the sapogenin. Madhuca saponins yielded a characteristic fragment of protobassic acid, whereas quillaja saponins showed a fragment of quillaic acid as expected. In addition, samples from madhuca seed kernels were analysed to verify the origin of the characteristic chromatographic peak pattern observed frequently in commercially available quillaja bark extracts.     

Synthesis and cytotoxic activity of the N-acetylglucosamine-bearing triterpenoid saponins

Fourteen ursolic acid and oleanolic acid saponins with N-acetyl-β-d-glucosamine, and (1→4)-linked and (1→6)-linked N-acetyl-β-d-glucosamine oligosaccharide residues were synthesized in a convergent manner. The structures of all compounds were confirmed by ¹H NMR and ¹³C NMR spectroscopy and by mass spectrometry, and their cytotoxic activities were assayed in three cancer cell lines. Only oleanolic acid-3-yl β-d-GluNAc showed significant cytotoxicity against HL-60 and BGC-823.     

A saponin tolerant and glycoside producer xylariaceous fungus isolated from fruits of <Emphasis Type="Italic">Sapindus saponaria</Emphasis>

The plant Sapindus saponaria is a good producer of terpenoidal and sesquiterpenoidal saponins, which are accumulated in its fruits. Although saponins usually act as antifungal compounds, a fungus was found living on the internal part of its pericarp. Tentative identification of the fungus, based on micro and macro-morphological aspects inspection, as well as on the secondary metabolite production, suggested the fungus to be a Xylariaceous microorganism. When the fungus is placed in contact with glycosides extracted from the host plant, or exogenous glycosides and other terpenoid compounds, it showed ability to transform them in another compounds. Analysis of these products using liquid chromatography and mass spectrometry showed that these biotransformations are mainly monohydroxylation and glycosilation. These findings contrasts most of the reports found in the literature which shows that hydrolysis at sugar chain are frequently observed during glycoside biotransformation by fungi.     

Synthesis and biological evaluation of Ginsenoside Compound K analogues as a novel class of anti-asthmatic agents

Ginsenoside Compound K (CK) showed potent activity against IgE for the treatment of asthma. A series of CK analogues were then synthesized by straightforward procedures. The in vivo anti-IgE activity evaluations using the OVA-induced asthmatic mouse model revealed preliminary SARs of the CK analogues, which showed that the sugar type, modifications on A-ring and the C20 side chain of CK all affected much on the activities. Primary SARs optimization led to the discovery of compounds T1, T2, T3, T8 and T12, which displayed superior or comparable anti-asthmatic effects (IgE value?=?1237.11?±?106.28, 975.82?±?160.32, 1136.96?±?121.85, 1191.08?±?107.59 and 1258.27?±?148.70?ng/mL, respectively) in comparison with CK (1501.85?±?184.66?ng/mL). These potent compounds could serve as leads for further development.     

Triterpenoid-biosynthetic UDP-glycosyltransferases from plants

Triterpenoid saponins are naturally occurring structurally diverse glycosides of triterpenes that are widely distributed among plant species. Great interest has been expressed by pharmaceutical and agriculture industries for the glycosylation of triterpenes. Such modifications alter their taste and bio-absorbability, affect their intra?/extracellular transport and storage in plants, and induce novel biological activities in the human body. Uridine diphosphate (UDP)-glycosyltransferases (UGTs) catalyze glycosylation using UDP sugar donors. These enzymes belong to a multigene family and recognize diverse natural products, including triterpenes, as the acceptor molecules. For this review, we collected and analyzed all of the UGT sequences found in Arabidopsis thaliana as well as 31 other species of triterpene-producing plants. To identify potential UGTs with novel functions in triterpene glycosylation, we screened and classified those candidates based on similarity with UGTs from Panax ginseng, Glycine max, Medicago truncatula, Saponaria vaccaria, and Barbarea vulgaris that are known to function in glycosylate triterpenes. We highlight recent findings on UGT inducibility by methyl jasmonate, tissue-specific expression, and subcellular localization, while also describing their catalytic activity in terms of regioselectivity for potential key UGTs dedicated to triterpene glycosylation in plants. Discovering these new UGTs expands our capacity to manipulate the biological and physicochemical properties of such valuable molecules.     

Association of saponin concentration,molecular markers,and biochemical factors with enhancing resistance to alfalfa seedling damping-off

Fifteen alfalfa populations were tested for resistance to the seedling damping-off disease sourced by Rhizoctonia solani, Fusarium solani, and Macrophomina phaseolina. In a laboratory experiment, saponin treatment significantly diminished the mycelial growth of the causal fungi of alfalfa damping-off disease. Roots of the fifteen alfalfa populations varied in saponin and lignin content. Selection for the considerably resistant plants leads to the best growth performance, desirable yield, and high nutritive values such as crude protein (CP), crude fier (CF), nitrogen free extract (NFE), ash, and ether extract (EE) contents. For the PCR reaction, 10 SSR pairs of the JESPR series primers and the cDNA-SCoT technique with seven primers were used. SSR and SCoT revealed some unique markers that could be linked to resistance to damping-off disease in alfalfa that appeared in the considerably resistant alfalfa population (the promised pop.). SSR and SCoT markers can be an excellent molecular method for judging genetic diversity and germplasm classification in tetraploid alfalfa. We recommend breeding for saponin concentration in the alfalfa plant may affect resistance to some diseases like root rot and damping-off because saponin might improve plant growth, yield, and nutritional values.     

Synthesis,antitumor activity evaluation and mechanistic study of novel hederacolchiside A1 derivatives bearing an aryl triazole moiety

In an attempt to arrive at a more potent antitumor agent than the parent natural saponin hederacolchiside A₁, 23 hederacolchiside A₁ derivatives (4a-4w) were synthesized via Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition and screened in vitro for cytotoxicity against six human cancer cell lines. The structure-activity relationship of these compounds was elucidated, and the biological screening results showed that most of the compounds exhibited moderate to high levels of antitumor activities against the tested cell lines and some of them displayed more potent inhibitory activities compared with hederacolchiside A₁. Compound 4f showed a 2- to 7-fold more potent activity than hederacolchiside A₁. The mechanistic study of 4f revealed that this compound can induce cell apoptosis in HepG2 cells via mitochondrial-mediated intrinsic pathways.     

Cycloartane glycosides from Astragalus aureus

Eight cycloartane-type triterpene glycosides (1-8) were isolated from Astragalus aureus Willd along with ten known cycloartane-type glycosides (9-18). Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. Compounds 1-5 are cyclocanthogenin glycosides, whereas compounds 6-8 are based on cyclocephalogenin as aglycon, more unusual in the plant kingdom, so far reported only from Astragalus spp. Moreover, for the first time monoglycosides of cyclocanthogenin (5) and cyclocephalogenin (7, 8) are reported. All of the compounds tested for their cytotoxic activities against a number of cancer cell lines. Among the compounds, only 8 exhibited activity versus human breast cancer (MCF7) at 45 μM concentration.     

Cytotoxic and antioxidant triterpene saponins from Butyrospermum parkii (Sapotaceae)

Three new triterpenoid saponins, elucidated as 3-O-β-d-glucopyranosyloleanolic acid 28-O-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranoside (parkioside A, 1), 3-O-[β-d-apifuranosyl-(1→3)-β-d-glucopyranosyl]oleanolic acid 28-O-[β-d-apifuranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)β-d-xylopyranoside (parkioside B, 2) and 3-O-β-d-glucuronopyranosyl-16α-hydroxyprotobassic acid 28-O-α-l-rhamnopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranoside (parkioside C, 3), were isolated from the n-BuOH extract of the root bark of Butyrospermum parkii, along with the known 3-O-β-d-glucopyranosyloleanolic acid (androseptoside A). The structures of the isolated compounds were established on the basis of chemical and spectroscopic methods, mainly 1D and 2D NMR data and mass spectrometry. The new compounds were tested for both radical scavenging and cytotoxic activities. Compound 2 showed cytotoxic activity against A375 and T98G cell lines, with IC₅₀ values of 2.74 and 2.93 μM, respectively. Furthermore, it showed an antioxidant activity comparable to that of Trolox or butylated hydroxytoluene (BHT), used as controls, against 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), oxygen and nitric oxide radicals.