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1.
Three new natural products, australisines A-C (1-3, resp.), were isolated from the stem bark of Morus australis, together with eight related compounds, including mulberrofurans E-G, J, and Q, mongolicin C, chalcomoracin, and kuwanon G. Their structures were fully characterized by spectroscopic methods. Compounds 1-3, mulberrofuran G, mongolicin C, and chalcomoracin showed moderate cytotoxic activities against five human cancer cell lines, with IC50 values ranging from 4.6-9.2 microg/ml, as determined by MTT assay. 相似文献
2.
Chemical investigation of the nonpolar extract of soft coral Clavularia viridis resulted in isolation of five new prostanoids, designated as claviridic acids A-E (1-5, resp.), in addition to the known clavulones I-III. Their structures were determined on the basis of spectroscopic techniques, especially HR-ESI-MS, CD, and 2D-NMR experiments. The isolated marine prostanoids exhibited potent inhibitory effect on PHA-induced proliferation of peripheral blood mononuclear cells (PBMC), as well as significant cytotoxic activity against human gastric cancer cells (AGS). 相似文献
3.
The optimization of a Diels-Alder reaction to prepare a novel ketone bearing a 2,3-dimethylnorbornyl group is presented together with the structure elucidation of the isomers. Employing this new ketone as starting material, derivatives with new woody odor notes as well as attempts to obtain ambery-musky odorants are reported. 相似文献
4.
Natural sandalwood oil, a unique and valuable ingredient in fine perfumery, has been the focus of scientific interest for many years. Due to its scarcity and its high price, the search for novel synthetic raw materials imitating the characteristic odor profile of sandalwood oil is as challenging as ever. In this context, the preparation of the novel sandalwood odorants 26, 33, and 39 will be discussed, including their sensory properties and structure-odor relationship. 相似文献
5.
Six new protopanaxadiol-type ginsenosides, named ginsenosides Ra(4) -Ra(9) (1-6, resp.), along with 14 known dammarane-type triterpene saponins, were isolated from the root of Panax ginseng, one of the most important Chinese medicinal herbs. The structures of the new compounds were determined by spectroscopic methods, including 1D- and 2D-NMR, HR-MS, and chemical transformation as (20S)- 3-O-{β-D-6-O-[(E)-but-2-enoyl]glucopyranosyl-(1→2)-β-D-glucopyranosyl}-20-O-[β-D-xylopyranosyl-(1→4)-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranosyl]protopanaxadiol (1), (20S)-3-O-[β-D-6-O-acetylglucopyranosyl-(1→2)-β-D-glucopyranosyl]-20-O-[β-D-xylopyranosyl-(1→4)-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranosyl]protopanaxadiol (2), (20S)-3-O-{β-D-6-O-[(E)-but-2-enoyl]glucopyranosyl-(1→2)-β-D-glucopyranosyl}-20-O-[β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl]protopanaxadiol (3), (20S)-3-O-{β-D-6-O-[(E)-but-2-enoyl]glucopyranosyl-(1→2)-β-D-glucopyranosyl}-20-O-[α-L-arabinopyranosyl-(1→6)-β-D-glucopyranosyl]protopanaxadiol (4), (20S)-3-O-{β-D-4-O-[(E)-but-2-enoyl]glucopyranosyl-(1→2)-β-D-glucopyranosyl}-20-O-[α-L-arabinofuranosyl-(1→6)-β-D-glucopyranosyl]protopanaxadiol (5), (20S)-3-O-{β-D-6-O-[(E)-but-2-enoyl]glucopyranosyl-(1→2)-β-D-glucopyranosyl}-20-O-[α-L-arabinofuranosyl-(1→6)-β-D-glucopyranosyl]protopanaxadiol (6). The sugar moiety at C(3) of the aglycone of each new ginsenoside is butenoylated or acetylated. 相似文献
6.
Five new D-ring-opened phragmalin-type limonoids, tabulalins A-E (1-5, resp.), were isolated from the stem bark of Chukrasia tabularis var. velutina. In the structures of these new isolates, the D-ring (C(16)/C(17) δ-lactone ring) of phragmalins was cleaved, and rare C(16)/C(30) δ-lactone ring in 1-3 or C(16)/C(8) γ-lactone ring in 4 and 5 were formed. The structures of these new compounds were elucidated based on extensive 1D- and 2D-spectroscopic analyses (HSQC, HMBC, and ROESY) and HR-ESI-MS. The major compounds, 2, 3, and 5, were evaluated for their inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a macrophage (RAW264.7) cell line with IC(50) values of 15.3±0.6, 13.0±0.5, and 17.1±0.7 μM, respectively. 相似文献
7.
Four new flavanones, cryptoflavanones A-D (1-4, resp.), together with eight known compounds, were isolated from the leaves of Cryptocarya chinensis. The structures of these new compounds were determined by spectral analyses. Among the isolated compounds, pinocembrin (5) and cryptocaryone (6) exhibited antituberculosis activity against Mycobacterium tuberculosis H(37) Rv strain in vitro with MIC values of 3.5 and 25.0 μg/ml, respectively. 相似文献
8.
Four new withanolides, physagulins L-O (1-4), were isolated from the MeOH extract of the aerial parts of Physalis angulata L. (Solanaceae), together with seven known withanolides, compounds 5-11. Their structures were determined by spectroscopic techniques, including 1H-, 13C-NMR (DEPT), and 2D-NMR (HMBC, HMQC, 1H,1H-COSY, NOESY) experiments, as well as by HR-MS. All eleven compounds were tested for their antiproliferative activities towards human colorectal-carcinoma (HCT-116) and human non-small-cell lung-cancer (NCI-H460) cells. Compound 5 exhibited the highest anticancer activity against the HCT-116 cell line, with an IC50 value of 1.64+/-0.06 microM. Compound 9 exhibited the highest cytotoxicity towards the NCI-H460 cell line, with an IC50 value of 0.43+/-0.02 microM. 相似文献
9.
Chemical examination of a Chinese soft coral Lobophytum pauciflorum resulted in the isolation of seven new biscembranoids named lobophytones U–Z1 ( 1 – 7 , resp.), together with methyl sartortuoate ( 8 ) and nyalolide ( 9 ). The structures of the new compounds were elucidated by 1D‐ and 2D‐NMR (COSY, HSQC, HMBC, and NOESY) spectroscopic analysis in association with MS and IR data. All compounds were tested against lipopolysaccharide (LPS)‐induced nitric oxide (NO) release in mouse peritoneal macrophage. Lobophytone Z ( 6 ) inhibited NO production with an IC50 value of 2.6 μM . Lobophytone H ( 1 ) showed inhibitory activities against the bacteria S. aureus and S. pneumoniae. 相似文献
10.
There is a need of antimicrobial compounds in agriculture for plant-disease control, with low toxicity and reduced negative environmental impact. Antimicrobial peptides are produced by living organisms and offer strong possibilities in agriculture because new compounds can be developed based on natural structures with improved properties of activity, specificity, biodegradability, and toxicity. Design of new molecules has been achieved using combinatorial-chemistry procedures coupled to high-throughput screening systems and data processing with design-of-experiments (DOE) methodology to obtain QSAR equation models and optimized compounds. Upon selection of best candidates with low cytotoxicity and moderate stability to protease digestion, anti-infective activity has been evaluated in plant-pathogen model systems. Suitable compounds have been submitted to acute toxicity testing in higher organisms and exhibited a low toxicity profile in a mouse model. Large-scale production can be achieved by solution organic or chemoenzymatic procedures in the case of very small peptides, but, in many cases, production can be performed by biotechnological methods using genetically modified microorganisms (fermentation) or transgenic crops (plant biofactories). 相似文献
11.
Four new alkaloids, daphnioldhanins D-G (1-4, resp.), together with five known alkaloids, daphmacropodine (5), secodaphniphylline (6), deoxycalyciphylline B (7), deoxyisocalyciphylline B (8), and daphmanidin A (9), were isolated from the roots of Daphniphyllum oldhami. Their structures were elucidated on the basis of spectroscopic data and chemical methods. Compound 1 at 2.0 microM showed potent antioxidant activity against H(2)O(2)-induced impairment in PC12 cells. 相似文献
12.
The naturally occurring tRNA nucleoside preQ(0), 7-cyano-7-deazaguanosine, which is a central intermediate for other natural occurring 7-deazapurine nucleosides was synthesized via a copper(I)-ion-mediated iodo→carbonitrile exchange. The reaction was performed on the easily accessible 7-iodo-7-deazaguanosine under microwave conditions. The overall reaction yield was 30% starting with the glycosylation reaction of the nucleobase. Corresponding 2'-deoxyribonucleosides were prepared following the same route. 相似文献
13.
Three new cytochalasins Z21–Z23 ( 1 – 3 , resp.), together with five analogs, 4 – 8 , were isolated from Spicaria elegans KLA03 by the OSMAC (one strain‐many compounds) approach with adding L ‐ and D ‐tryptophan during its cultivation. The structures of new cytochalasins were elucidated on the basis of comprehensive 1D‐ and 2D‐NMR and HR‐ESI‐MS analyses. Cytochalasins Z21 and Z22 ( 1 and 2 , resp.), and compound 5 showed cytotoxic activities against A‐549 cell lines with IC50 values of 8.2, 20.0, and 3.1 μM , respectively. 相似文献
14.
Three new coumarinolignoids, malloapelins A-C (1-3, resp.), together with three known coumarinolignoids, cleomiscosin A (4), cleomiscosin B (5), and 5'-demethylaquillochin (6), were isolated from the roots of Mallotus apelta MUELL.-ARG. Compounds 1-6 are three pairs of regioisomeric coumarinolignoids. Their structures were elucidated on the basis of spectral evidence. Compounds 3 showed promising hepatoprotective activity against D-galactosamine-induced toxicity in WB-F344 rat hepatic epithelial stem-like cells. 相似文献
15.
Lin HY Chiu HL Lan YH Tzeng CY Lee TH Lee CK Shao YY Chen CR Chang CI Kuo YH 《化学与生物多样性》2011,8(9):1701-1708
Four new lactone chlorins, ficuschlorins A – D ( 1 – 4 , resp.), and six known pheophytins were isolated from the leaves of Ficus microcarpa. The structures of these compounds were determined by 1D‐ and 2D‐NMR spectroscopy, and other techniques. New natural pheophytins were rarely obtained. In the past ten years, only three new pheophytins were isolated from natural sources. 相似文献
16.
Bioassay-guided fractionation of the acetone extract of the roots of Casearia membranacea furnished three new clerodane diterpenes, caseamembrins S-U (1-3) and the known caseamembrin Q (4). Their structures were established by extensive spectroscopic analyses, especially 2D-NMR. Compounds 1-4 were tested against human tumor cells, including HeLa (cervical epitheloid carcinoma), DLD-1 (colon carcinoma), Daoy (medulloblastoma), and KB (oral epidermoid carcinoma) cell lines. Caseamembrin T (2) exhibited the most potent activity against Daoy cells (ED(50)=10 ng/ml), superior to that of the standard drug mitomycin. 相似文献
17.
Copper (Cu) metallothioneins are cuprous-thiolate proteins that contain multimetallic clusters, and are thought to have dual functions of Cu storage and Cu detoxification. We have used a combination of X-ray absorption spectroscopy (XAS) and density-functional theory (DFT) to investigate the nature of Cu binding to Saccharomyces cerevisiae metallothionein. We found that the XAS of metallothionein prepared, containing a full complement of Cu, was quantitatively consistent with the crystal structure, and that reconstitution of the apo-metallothionein with stoichiometric Cu results in the formation of a tetracopper cluster, indicating cooperative binding of the Cu ions by the metallothionein. 相似文献
18.
Kraft P 《化学与生物多样性》2008,5(6):970-999
This review, including new experimental results, is the summary of a talk at the RSC/SCI conference 'flavours & fragrances 2007' in London, Imperial College, 24-26 September, 2007. Though the third dimension of the receptor models of J. E. Amoore rarely was exceeding 4 A, the world of woody odorants such as (+)-cedrol (3; cedarwood), (-)-khusimone (4; vetiver), and (-)-patchoulol (5; patchouli) is anything but flat. Any tricyclic skeleton with a zero-bridge contains a spirocyclic ring system determining its 3D structure, so spirocycles (spira, Lat. pretzel) are the fastest access to the third dimension. In the vetiver family, a spirocyclic mimic 9 of (-)-khusimone (4) was first discovered by chance by Büchi in 1976, and also by chance, we obtained another system, 12, with a characteristic vetiver smell by tandem-Rupe-Nazarov reaction of alkyne diols. A 5-A distance between a quaternary C-atom and a carbonyl group (or alternative HB acceptor) with an alpha-methyl or methylene branching is proposed to be the key to their vetiver odor. Upon scale-up of one of these odorants, 24, we discovered a very powerful (0.067 ng/l) impurity with a most typical patchouli scent: the spirocyclic, sterically crowded hydroxy ketone 33--a most unusual structure for a patchouli odorant. Several spirocyclic hydroxy ketone analogs, also with inverted ring systems such as in 70 and 84, provided new insights into the structure-odor correlation of this family. A superposition analysis indicated the carbonyl function of the hydroxy ketone to overlay on the geminal dimethyl motive of (-)-patchoulol. And indeed, the corresponding hydroxy ketone of patchoulol, 59, synthesized in 13 steps from Cyclal C (63), also emanated a patchouli odor. Finally, the synthesis and olfactory properties of twelve rigid spirocyclic analogs, 95-97, 99-102, and 106-110, of Georgywood (91) are presented that highlight stereochemical requirements for woody odorants and raise doubts about an alpha-helical binding motive postulated by Hong and Corey. 相似文献
19.
Instrumental and sensory approaches for the characterization of compounds responsible for wine aroma
More than 800 aromatic compounds have been identified in wine, some of them at the ng/l level. Wine, therefore, constitutes a very complex matrix, from which it is difficult to isolate a specific aroma character. Gas chromatography-olfactometry (GC-O) applied to wine extracts is used to characterize odor-active zones that are often treated in a hierarchical way by Aroma Extract Dilution Analysis (AEDA). The aromatic impact of the volatiles is evaluated, generally by determining perception thresholds. This methodology has provided convincing results concerning wine flavors, but it does have its limitations. For instance, data on beta-damascenone have demonstrated that these methods could reach their limits for this volatile, in particular, because of the non-quantitative representation of aroma extracts of wines, and because of the difficulty to accurately determine the perception threshold in wines for a compound already present. For beta-damascenone, we have shown that its very low detection threshold with GC-O, its wide range, and its dependence on the composition of the medium resulted in overestimating its direct impact on the aroma of wine. Another way to facilitate the characterization of aromatic compounds was, therefore, investigated. High-Performance Liquid Chromatography (HPLC) methods were developed for the analysis of wine extracts. From an aromatic extract, 25 fractions with various flavors were thus obtained, and reverse-phase methodology was used for the selection and characterization of red- and black-fruit aromas in red wines. 相似文献
20.
A short survey of historic and current methods for the synthesis of selenocysteine, selenocystine, and derivatives and related compounds is presented, with an additional emphasis on the formation of selenocysteine-derived Se-S bridges. The majority of methods to the amino acid starts with protected and O-activated serine, but also other concepts are included such as radical or multicomponent strategies, the latter allowing also direct access to peptoids in one pot. Of special importance is the monomeric oxidative cyclization of selenocysteine-cysteine peptides to eight-membered and larger rings with a selenenylsulfide bridge, a crucial element in several selenoproteins. 相似文献