Chemical investigation of the leaves of Bupleurum lancifolium led to the isolation and identification of two triterpenoid saponins previously undescribed named 3-O-α-L-rhamnopyranosyl ...(1 → 4)-β-D-glucopyranosyl echinocystic acid 28-O-β-D-glucopyranosyl ester (1) and 3-O-α-L-rhamnopyranosyl (1 → 4)-β-D-glucopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl ester (2) along with the two known compounds isorhamnetin 3-rutinoside (3) and rutin (4). Their structures were elucidated by different spectroscopic methods, including HRESIMS analysis as well as 1D and 2D NMR experiments.
Although different mechanisms have been proposed in the recent years, plant pathogen partial resistance is still poorly understood. Components of the chemical warfare, including the production of ...plant defense compounds and plant resistance to pathogen-produced toxins, are likely to play a role. Toxins are indeed recognized as important determinants of pathogenicity in necrotrophic fungi. Partial resistance based on quantitative resistance loci and linked to a pathogen-produced toxin has never been fully described. We tested this hypothesis using the Alternaria dauci-carrot pathosystem. Alternaria dauci, causing carrot leaf blight, is a necrotrophic fungus known to produce zinniol, a compound described as a non-host selective toxin. Embryogenic cellular cultures from carrot genotypes varying in resistance against A. dauci were confronted with zinniol at different concentrations or to fungal exudates (raw, organic or aqueous extracts). The plant response was analyzed through the measurement of cytoplasmic esterase activity, as a marker of cell viability, and the differentiation of somatic embryos in cellular cultures. A differential response to toxicity was demonstrated between susceptible and partially resistant genotypes, with a good correlation noted between the resistance to the fungus at the whole plant level and resistance at the cellular level to fungal exudates from raw and organic extracts. No toxic reaction of embryogenic cultures was observed after treatment with the aqueous extract or zinniol used at physiological concentration. Moreover, we did not detect zinniol in toxic fungal extracts by UHPLC analysis. These results suggest that strong phytotoxic compounds are present in the organic extract and remain to be characterized. Our results clearly show that carrot tolerance to A. dauci toxins is one component of its partial resistance.
Advanced glycation end-products (AGEs) are involved in the pathogenesis of numerous affections such as diabetes and neurological diseases. AGEs are also implied in various changes in tissues and ...organs. Therefore, compounds able to break them or inhibit their formation may be considered as potential drugs, dietary supplements, or bioactive additives. In this study, we have developed a rapid and reliable (Z′ factor calculation) anti-AGEs activity screening based on the overall fluorescence of AGEs. This method was successfully evaluated on known AGEs inhibitors and on a small library of natural compounds, yielding coherent results when compared with literature data.
•A small database was acquired from 11 4-phenylcoumarins using LC-DAD–MSn analysis.•24 known mammea coumarins were dereplicated from Mammea neurophylla DCM extracts.•The structure of 4 unreported ...mammea coumarins could be predicted.•2 new mammea coumarins were confirmed after purification and NMR analyses.
Mammea coumarins are isoprenylated 4-alkyl or 4-phenylcoumarins. Their distribution is limited to 3 Clusiaceae/Calophyllaceae genera. We recently reported on their presence in Mammea neurophylla bark extracts, where they exhibited anti-AGE properties associated with a prevention of the endothelial dysfunction. About 120 mammea coumarins were already described so, in order to focus further phytochemical analysis on original or bio-active compounds, we developed a methodology to facilitate the detection and identification of compounds of interest. Our aim was to develop a LC-DAD–ESI-MSn method for rapid, sensitive and simple analysis of the mammea coumarins in calophyllaceous/clusiaceous species. For that, full LC-DAD–MSn data were acquired from 11 4-phenylcoumarins previously isolated in our laboratory. Bark, leaves and fruits of M. neurophylla were then extracted with DCM using an ASE apparatus. Extracts were finally analyzed through LC-DAD–HRMSn and UV and MS profiles were compared to our database as well as literature data. Detected new compounds were isolated and their structures elucidated through 1H, 13C and 2D NMR analysis. Finally, 24 known mammea coumarins were dereplicated from bark, leaf and fruit DCM extracts of M. neurophylla and the structure of 4 unreported compounds could be predicted. In particular, the structures of mammea A/AA 9-hydroxyCycloF and mammea A/AB 9-hydroxyCycloF were confirmed after purification and extensive NMR analyses. By comparison of UV and mass fragmentation data from a small library of reference compounds, LC-DAD–HRMSn analysis of mammea coumarins in crude extracts allows the structure prediction of novel or bio-active compounds. This useful guiding-tool could be easily applied to other Clusiaceae/Calophyllaceae phytochemical analysis.
Six coumarins have been isolated from the fruits and the stem bark of
Calophyllum dispar (Clusiaceae). The structures of these minor components were established by means of spectroscopic analysis, ...including extensive 2D NMR studies. Some of these coumarins exhibited a significant cytotoxic activity against KB cells.
Six coumarins have been isolated from the fruits and the stem bark of
Calophyllum dispar (Clusiaceae). Some of these coumarins exhibited a significant cytotoxic activity against KB cells.
Advanced glycation end-products, namely AGEs, are involved in the pathogenesis of numerous diseases. If AGEs inhibitors are well-known, only few products are described as compounds able to destroy ...those deleterious products. In this work, we describe naphthoic acid derivatives, particularly 1-(naphthalen-1-yl)propane-1,2-dione 9, allowing the simple and rapid detection of AGEs breakers using a 96-well microplate fluorescence assay. Since the inaugurate publication about AGEs breakers whose activity was demonstrated using HPLC analysis, this work proposes the first assay suitable for automated and high throughput screening of AGEs breakers.
The synthesis of five light absorbing triazolobithiophenic thiols, which were utilized for producing self-assembled monolayers (SAMs) on gold surfaces, is presented. The monolayer formation was ...monitored by cyclic voltammetry, indicating excellent surface coverage. The new triazolobithiophenic compounds exhibited an absorption maximum around 340 nm, which is close to the emission wavelength of a standard nitrogen laser. Consequently these compounds could be used to aid ionization in laser desorption mass spectrometry (MS).
Three new 1-thioglycosides namely methylthiomethyl 1-thio-β-
d-glucopyranoside (Afrostyraxthioside A), methylsulfonylmethyl 1-thio-β-
d-glucopyranoside (Afrostyraxthioside B) and ...methylsulfonylmethylthiomethyl 1-thio-β-
d-glucopyranoside (Afrostyraxthioside C) were isolated from the seeds of
Afrostyrax lepidophyllus Mildbr. Their structures were mainly elucidated by using one- and two-dimensional NMR and mass spectroscopies and also by an efficient one-step synthesis. Moreover, Afrostyraxthiosides A, B and C constitute a new subclass of 1-thioglycosides isolated from natural sources.
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•One new isflavonoid, named derrisisoflavone G (1) with 10 compounds (2–11) were isolated from stems and leaves of Derris ferruginea plants.•Compounds (1–5) were isolated for the ...first time from the genus Derris.•Compounds 1–5 were found to possess anti-AGEs activity.•The structure of compound 1 was confirmed by its hemi-synthesis.
A new isoflavonoid, 5-hydroxy-3-(4-hydroxyphenyl)-8-isopropenyl-8,9-dihydro-4H-furo-2,3-h-chromen-4-one named derrisisoflavone G (1), four known prenylated flavanones (2–5), four known isoflavonoids (6–9) and two phenolic derivatives (10, 11) have been isolated from crude extracts of Derris ferruginea stems and leaves. Compounds 1–11 were identified using spectroscopic methods whereas an unambiguous structural assignment of 1 was accomplished through hemi-synthesis. Compounds 2–5 exhibited strong in vitro antiparasitic activity against Plasmodium falciparum and Leishmania major but with poor selectivity, whereas 1–5 significantly inhibited the formation of advanced glycation endproducts (AGEs).
The semisynthesis of xanthanolide derivatives is reported from xanthinin and 4-epi-isoxanthanol, two sesquiterpene lactones isolated from the crude chloroformic extract of the leaves of Xanthium ...macrocarpum DC. (Asteraceae) by liquid/liquid chromatography. In vitro evaluation of their protein farnesyltransferase (PFTase) inhibitory activity has been investigated. In contrast to other biological activities of xanthanolides, PFTase inhibition is not associated with the presence of the potentially toxic α-methylene-γ-lactone function.
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