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p. 1219-1229
Received: 6 May 2008 / Accepted: 29 May 2008 / Published: 1 June 2008
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| Download PDF Full-text (130 KB) Abstract: Dragon’s blood (Sangre de drago), a viscous red sap derived from Croton lechleri Muell-Arg (Euphorbiaceae), is extensively used by indigenous cultures of the Amazonian basin for its wound healing properties. The aim of this study was to identify the minor secondary metabolites and test the antioxidant activity of this sustance. A bioguided fractionation of the n-hexane, chloroform, n-butanol, and aqueous extracts led to the isolation of 15 compounds: three megastigmanes, four flavan-3-ols, three phenylpropanoids, three lignans, a clerodane, and the alkaloid taspine. In addition to these known molecules, six compounds were isolated and identified for the first time in the latex: blumenol B, blumenol C, 4,5-dihydroblumenol A, erythro-guaiacyl-glyceryl-β-O-4’- dihydroconiferyl ether, 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-propane-1,3-diol and floribundic acid glucoside. Combinations of spectroscopic methods (1 H-, 13 C- NMR and 2D-NMR experiments), ESI-MS, and literature comparisons were used for compound identification. In vitro antioxidant activities were assessed by DPPH, total antioxidant capacity and lipid peroxidation assays. Flavan-3-ols derivatives (as major phenolic compounds in the latex) exhibited the highest antioxidant activity.
p. 1230-1237
Received: 29 April 2008; in revised form: 12 May 2008 / Accepted: 15 May 2008 / Published: 1 June 2008
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| Download PDF Full-text (52 KB) Abstract: Aromatic and aliphatic oximes have been deoximated in chloroform-water to the corresponding aldehydes with dilute hydrogen peroxide and triscetylpyridinium tetrakis (oxodiperoxotungsto) phosphate as catalyst. The presence of dipolarophiles in the reaction mixtures allows a competitive reaction that converts oximes into isoxazole and isoxazoline derivatives via the intermediate formation of nitrile oxide species.
p. 1238-1245
Received: 5 May 2008; in revised form: 29 May 2008 / Accepted: 29 May 2008 / Published: 1 June 2008
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| Download PDF Full-text (176 KB) Abstract: Following the development of new applications of pilot plant scale extraction and formulation processes for natural active bioproducts obtained from various underutilized tropical plants and herbs, we have manufactured water-extracts from Delonix regia flowers, grown in Ivory Coast. These extracts, which contain polyphenols, are traditionally home made and used as healthy bioproducts. They are reddish-coloured due to the presence of anthocyanins. The three major anthocyanins in these extracts have been characterized. The molecular structures were confirmed by LC-SM analysis. Amongst them, two are described for the first time in Delonix regia .
p. 1246-1252
Received: 25 April 2008; in revised form: 26 May 2008 / Accepted: 28 May 2008 / Published: 3 June 2008
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| Download PDF Full-text (178 KB) Abstract: Density Functional Theory (DFT) calculations have been performed on the TTC→TTT isomerization reaction of the open forms of the 1',3'-dihydro-8-bromo-6-nitro- 1',3',3'-trimethylspiro[2H-1-benzopyran-2,2'-(2H)indole (8-Br-6-nitro-BIPS) system. The calculations were carried out in vacuo and in methylene chloride solution at different temperatures. Results are compared with the available experimental values of free energy difference and activation energy in solution.
p. 1253-1262
Received: 30 April 2008; in revised form: 2 June 2008 / Accepted: 3 June 2008 / Published: 4 June 2008
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| Download PDF Full-text (316 KB) Abstract: The crude extract of the Brazilian brown alga Dictyota crenulata was analyzed by NMR spectroscopy and HRGC-MS techniques. Seven diterpenes were identified: pachydictyol A, dictyodial, 4β-hydroxydictyodial A, 4β-acetoxydictyodial A, isopachydictyol A, dictyol C and dictyotadiol. Xeniane diterpenes have previously been found in D. crenulata from the Pacific Ocean. The results characterize D. crenulata as a species that provides prenylated guaiane (group I) and xeniane diterpenes (group III), thus making it a new source of potential antiviral products.
p. 1263-1274
Received: 24 April 2008; in revised form: 8 May 2008 / Accepted: 9 May 2008 / Published: 6 June 2008
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| Download PDF Full-text (147 KB) Abstract: Chitosan (CS) was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell’s dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source) Artemia CS exhibited a medium molecular weight (4.5-5.7 ×105 Da), lower degree of deacetylation (67-74%) and lower viscosity (29-91 centiposes). The physicochemical characteristics (e.g., ash, nitrogen and molecular weight) and functional properties (e.g., water binding capacity and antibacterial activity) of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence.
p. 1275-1281
Received: 23 May 2008; in revised form: 5 June 2008 / Accepted: 5 June 2008 / Published: 6 June 2008
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| Download PDF Full-text (133 KB) Abstract: Detailed chemical investigation of the South China sponge Dysidea arenaria resulted in the isolation of a new sesquiterpenoid hydroquinone, 19-hydroxypolyfibrospongol B (1), along with five known compounds: polyfibrospongol B (2), isosemnonorthoquinone (3), ilimaquinone (4), smenospongine (5) and smenotronic acid (6). The structures were determined by extensive spectroscopic analysis. The in vitro anti- HIV activity on HIV-1 RT was evaluated. Compounds 3 -6 displayed moderate inhibitory activity, with IC50 values of 239.7, 16.4, 176.1, and 130.4 μM, respectively, while 1 and 2 were found to be inactive against the same biological target.
p. 1282-1302
Received: 15 May 2008; in revised form: 6 June 2008 / Accepted: 6 June 2008 / Published: 9 June 2008
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| Download PDF Full-text (168 KB) Abstract: Meisenheimer complexes are important intermediates in Nucleophilic Aromatic Substitution Reactions (SN Ar). They are formed by the addition of electron rich species to polynitro aromatic compounds or aromatic compounds with strong electron withdrawing groups. It is possible to distinguish two types of Meisenheimer or σ-complexes, the σH complex or σX -complex (also named ipso), depending on the aromatic ring position attacked by the nucleophile (a non-substituted or substituted one, respectively). Special examples of σX - or ipso-complexes are formed through intermediate spiro adducts, via intramolecular SNAr. Some of these spirocyclic Meisenheimer complexes, a type of σX complex, are exceptionally stable in solution and/or as solids. They can be isolated and characterized using X-ray, and various spectroscopic techniques such as NMR, UV-Vis, IR, and fluorescence. A few of these stable spirocyclic Meisenheimer complexes are zwitterionic and exhibit interesting photophysical and redox properties. We will review recent advances, synthesis and potential applications of these stable spirocyclic Meisenheimer complexes.
p. 1303-1311
Received: 29 May 2008; in revised form: 5 June 2008 / Accepted: 6 June 2008 / Published: 9 June 2008
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| Download PDF Full-text (139 KB) Abstract: Addition of carboxylic acid dianions appears to be a potential alternative to the use of aluminium enolates for nucleophilic ring opening of epoxides. These conditions require the use of a sub-stoichiometric amount of amine (10% mol) for dianion generation and the previous activation of the epoxide with LiCl. Yields are good, with high regioselectivity, but the use of styrene oxide led, unexpectedly, to a mixture resulting from the attack on both the primary and secondary carbon atoms. Generally, a low diastereoselectivity is seen on attack at the primary center, however only one diastereoisomer was obtained from attack to the secondary carbon of the styrene oxide.
p. 1312-1320
Received: 3 June 2008; in revised form: 10 June 2008 / Accepted: 10 June 2008 / Published: 11 June 2008
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| Download PDF Full-text (63 KB) Abstract: A synthetic method for the preparation of 6-aryl-1,4-dimethyl-9H-carbazoles involving a palladium catalyzed coupling reaction of 1,4-dimethyl-9H-carbazole-6-boronic acids and (hetero)aryl halides is described.
p. 1321-1332
Received: 7 May 2008; in revised form: 7 June 2008 / Accepted: 8 June 2008 / Published: 12 June 2008
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| Download PDF Full-text (147 KB) Abstract: Walnut leaves from nine different cultivars (Arco, Franquette, Hartley, Lara, Marbot, Mayette, Meylannaise, Parisienne and Rego) were studied for their phenolic compounds. Samples were harvested along three consecutive years, at two different geographical locations, in order to evaluate if significant differences in the phenolics composition can be related with genetic, climatic or geographical factors. Nine compounds (3-caffeoylquinic, 3-p-coumaroylquinic and 4-p-coumaroylquinic acids, quercetin 3- galactoside, quercetin 3-arabinoside, quercetin 3-xyloside, quercetin 3-rhamnoside, a quercetin 3-pentoside derivative and a kaempferol 3-pentoside derivative) were quantified using an HPLC-DAD methodology. The qualitative profiles were identical for all samples, but differences were observed in terms of individual compounds’ contents. Multivariate statistical analysis was carried out, showing that significant differences exist among production years, which can be related to climatic reasons.
p. 1333-1344
Received: 20 April 2008; in revised form: 19 May 2008 / Accepted: 19 May 2008 / Published: 12 June 2008
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| Download PDF Full-text (240 KB) Abstract: Gas chromatography-mass spectrometry (GC-MS) and gas chromatographyolfactometry (GC-O) were used to determine the aromatic composition and aroma active compounds of fruit juice and peel oil of Jinchen sweet orange fruit. Totals of 49 and 32 compounds were identified in fruit juice and peel oil, respectively. GC-O was performed to study the aromatic profile of Jinchen fruit juice and peel oil. A total of 41 components appeared to contribute to the aroma of fruit juice and peel oil. Twelve components were the odorants perceived in both samples. The aromatic compositions of fruit juice were more complex than that of peel oil. Ethyl butanoate, β-myrcene, octanal, linalool, α-pinene, and decanal were found to be responsible for the aromatic notes in fruit juice and peel oil. Nineteen components have been perceived only in the juice and ten compounds were described as aromatic components of only the peel oil by the panelists. These differences lead to the different overall aroma between fruit juice and peel oil.
p. 1345-1352
Received: 1 June 2008; in revised form: 10 June 2008 / Accepted: 10 June 2008 / Published: 12 June 2008
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| Download PDF Full-text (96 KB) Abstract: Lithium, used in conjunction with sodium metal, produces a high yield of carbazole when reacted with phenothiazine-5-oxide or phenothiazine-5,5-dioxide. A high yield of 9-ethylcarbazole is also produced when these reagents react with 10-ethylphenothiazine, 10-ethylphenothiazine-5-oxide, and 10-ethylphenothiazine-5,5-dioxide. Degassed Raney nickel produces carbazole in high yield when reacted with phenothiazine and phenothiazine-5-oxide. A moderate yield of 9-ethylcarbazole is produced when n-butyllithium is reacted with 10-ethylphenothiazine-5-oxide.
p. 1353-1360
Received: 6 May 2008; in revised form: 26 May 2008 / Accepted: 26 May 2008 / Published: 13 June 2008
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| Download PDF Full-text (119 KB) Abstract: The syntheses of some diheterocyclic compounds from 2-thioacetohydrazide- 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (1) are described. Compound 1 can be converted into triazoles, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles. The structures of the intermediates and the target compounds were confirmed by 1 H-NMR, MS and elemental analyses.
p. 1361-1371
Received: 9 May 2008; in revised form: 3 June 2008 / Accepted: 3 June 2008 / Published: 16 June 2008
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| Download PDF Full-text (295 KB) Abstract: Two new alkaloids, 9-methoxy-18,19-dehydrocamptothecin (1) and 5- hydroxymappicine-20-O-β-glucopyranoside (2a/2b as a racemic mixture), together with nine known compounds: camptothecin (3), 9-methoxy-camptothecin (4), 5-hydroxycamptothecin (5a/5b racemic mixture), 5-hydroxy-9-methoxycamptothecin (6a/6b racemic mixture), diosmetin (7), apigenin (8), apigenin-7-O-glucopyranoside (9), rosin (cinnamyl- O-β-D-glucopyranoside) (10) and amarantholidoside IV (11) were isolated from the immature seeds of Nothapodytes foetida (Wight) Sleumer. The structures were elucidated by spectroscopic analyses. In the present research, compounds 1, 3, 4, 5a/5b and 6a/6b, also showed in vitro cytotoxicity against six cancer cell lines (HepG2, Hep3B, MDA-MB- 231, MCF-7, A549, and Ca9-22). Among them, compound 1 exhibited significant cytotoxicity against these cancer cell lines, with IC50 of 0.24-6.57 μM. Furthermore, HPLC profiles were developed for qualitative and quantitative analysis of these active constituents in different parts of this plant, including mature and immature seeds, leaves, stems and roots. The results revealed that compounds 3 and 4 have the highest concentrations, which are found in the roots part of the plant.
p. 1372-1383
Received: 3 June 2008; in revised form: 18 June 2008 / Accepted: 18 June 2008 / Published: 19 June 2008
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| Download PDF Full-text (283 KB) Abstract: The high-throughput screening and drug discovery paradigm has necessitated a change in preparation of natural product samples for screening programs. In an attempt to improve the quality of marine natural products samples for screening, several fractionation strategies were investigated. The final method used HP20SS as a solid support to effectively desalt extracts and fractionate the organic components. Additionally, methods to integrate an automated LCMS fractionation approach to shorten discovery time lines have been implemented.
p. 1384-1398
Received: 30 May 2008; in revised form: 17 June 2008 / Accepted: 17 June 2008 / Published: 19 June 2008
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| Download PDF Full-text (412 KB) Abstract: Recent studies concerning the isolation and purification of exopolysaccharides from suspension-cultured tomato (Lycopersicon esculentum L. var. San Marzano) cells and the description of a simple, rapid and low environmental impact method with for obtaining polysaccharides from solid tomato-processing industry wastes are reported. Their chemical composition, rheological properties and partial primary structure were determined on the basis of spectroscopic analyses (UV, IR, GC-MS, 1 H-, 13 C-NMR). Moreover, the anticytotoxic activities of exopolysaccharides obtained from cultured tomato cells were tested in a brine shrimp bioassay and the preparation of biodegradable film by chemical processing of polysaccharides from solid tomato industry waste was also reported.
p. 1399-1405
Received: 4 June 2008; in revised form: 17 June 2008 / Accepted: 17 June 2008 / Published: 19 June 2008
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| Download PDF Full-text (151 KB) Abstract: Detailed chemical investigation of the herb Sarcopyramis bodinieri var. delicate resulted in the isolation of two new flavonol glycosides, namely, isorhamnetin-3-O-(6′′-OE- feruloyl)-β-D-glucopyranoside (1) and isorhamnetin-3-O-(6′′-O-E-feruloyl)-β-Dgalactopyranoside (2). In addition, four known compounds, quercetin-3-O-(6′′-acetyl)-β-Dglucopyranoside (3), isorhamnetin-3-O-(6′′-acetyl)-β-D-glucopyranoside (4), quercetin-3- O-(6′′-O-E-p-coumaroyl)-β-D-glucopyranoside (5), and isorhamnetin-3-O-(6′′-O-E-pcoumaroyl)- β-D-glucopyranoside (6) were obtained. The structures of the new isolates were determined by extensive spectroscopic analysis.
p. 1406-1426
Received: 30 May 2008 / Accepted: 16 June 2008 / Published: 20 June 2008
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| Download PDF Full-text (487 KB) Abstract: From the beginning of the antibiotic era in the 1940s to the present, Wyeth has sustained an active research program in the area of natural products discovery. This program has continually evolved through the years in order to best align with the “current” drug discovery paradigm in the pharmaceutical industry. The introduction of highthroughput screening and the miniaturization of assays have created a need to optimize natural product samples to better suit these new technologies. Furthermore, natural product programs are faced with an ever shortening time period from hit detection to lead characterization. To address these issues, Wyeth has created a pre-fractionated natural products library using reversed-phase HPLC to complement their existing library of crude extracts. The details of the pre-fractionated library and a cost-benefit analysis will be presented in this review.
p. 1427-1440
Received: 2 June 2008; in revised form: 22 June 1995 / Accepted: 23 June 2008 / Published: 24 June 2008
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| Download PDF Full-text (164 KB) Abstract: A series of novel substituted 1,2,3-benzotriazines based on the structures of vatalanib succinate (PTK787) and vandetanib (ZD6474) were designed and synthesized. The antiproliferative effects of these compounds were tested on microvascular endothelial cells (MVECs) using the MTT assay. Introduction of a methoxy and a 3-chloropropoxy group into the 1,2,3-benzotriazines increased the antiproliferative effects. 4-(3-Chloro-4- fluoroanilino)-7-(3-chloropropoxy)-6-methoxy-1,2,3-benzotriazine (8m) was the most effective compound. It was 4-10 fold more potent than PTK787 in inhibiting the growth of T47D breast cancer cells, DU145 and PC-3 prostate cancer cells, LL/2 murine Lewis lung cancer cells and B16F0 melanoma cells.
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