Three New Polyprenylated Benzophenone Derivatives Isolated from Clusia burle-marxii.

Three new polyprenylated benzophenone derivatives named burlemarxiones G-I (1-3) were isolated from C. burle-marxii trunks (compound 1) and leaves (compounds 2 and 3), along with the known compound burlemarxione F. Burlemarxione G (1) was isolated after methylation with diazomethane and it is the keto-enol tautomeric pair of burlemarxione F.

Antioxidant activity of an Mg(II) compound containing ferulic acid as a chelator: potential application for active packaging and riboflavin stabilisation.

Foods rich in riboflavin (Rf) are susceptible to degradation due to oxidative processes with the formation of radicals. Herein, we describe the features and stability of an Mg(II) complex containing ferulic acid (fer) and 1,10-phenanthroline (phen) as chelators: henceforth called Mg(phen)(fer). The electrochemical behavior of Mg(phen)(fer) is pH dependent and results from the stabilisation of the corresponding phenoxyl radical complexation with Mg(II).

Synthesis, Characterization, and Low-Toxicity Study of a Magnesium(II) Complex Containing an Isovanillate Group.

The beneficial effect of polyphenols and magnesium(II) against oxidative stress motivated our research group to explore the antioxidant activity of phenMgIso, an aqueous soluble magnesium(II) complex containing 1,10-phenanthroline (phen) and isovanillic acid (Iso) as ligands. Combined electrospray ionization-mass spectrometry and DOSY-NMR techniques identified two complexes in methanolic solution: hexacoordinated [Mg(phen)(Iso)] and tetracoordinated [Mg(phen)(Iso)]. The cyclic voltammogram of phenMgIso in the anodic region showed a cyclic process that interrupts the isovanillic acid degradation, probably by stabilization of the corresponding phenoxyl radical via complexation with Mg(II), which is interesting for antioxidant applications.

Prostaglandins E and F levels in human menstrual fluid by online Solid Phase Extraction coupled to Liquid Chromatography tandem Mass Spectrometry (SPE-LC-MS/MS).

This paper reports an online SPE-LC-MS/MS method for the simultaneous quantification of prostaglandins (PGE and PGF) in menstrual fluid samples. To meet this goal human peripheral serum was used as surrogate matrix. The analytes were trapped on an OASIS HLB cartridge for 3 min, for sample cleanup and enrichment, and then transferred during only 42 s to an HSS T3 C18 analytical column, for separation and analysis.

Identification of Meliatoxins in Melia azedarach Extracts Using Mass Spectrometry for Quality Control.

Indiscriminate use of synthetic pesticides can be hazardous to both humans and the environment, but the use of natural products as a source of bio-based products, such as extracts, is an interesting approach to overcome these hazards. Unfortunately, the limonoids found in with desired insecticidal properties (e.g.

Unusual 2(1H)-pyrazinones isolated from a culture of a Brazilian marine-derived Streptomyces sp.

Four new secondary metabolites, giovaninones A-D (1-4), were isolated from an ethyl acetate extract of a culture of a marine-derived Streptomyces strain designated SS99BA-2. Chemical analysis was completely conducted in a coupled automated LC-SPE system with the use of a cryogenic NMR probehead and HRMS. The application of this system to identify, purify and elucidate all the structures is described.

Natural compounds with cell growth inhibitory activity in human tumor cell lines.

Twenty six compounds (coumarins, flavonoids and alkaloids) were evaluated for their ability to inhibit the growth of three human tumor cell lines: breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and melanoma (A375-C5). Three of them [3-hydroxyflavone (6), 2'-hydroxy-3,4,4',5,6'-pentamethoxychalcone (11), Siderin (20)] were very potent in inhibiting all human tumor cell lines tested. The structure / activity relationship is discussed.

Isolation of xanthyletin, an inhibitor of ants' symbiotic fungus, by high-speed counter-current chromatography.

Xanthyletin, an inhibitor of symbiotic fungus (Leucoagaricus gongylophorus) of leaf-cutting ant (Atta sexdens rubropilosa), as well as suberosin, seselin and xanthoxyletin were isolated from Citrus sinensis grafted on Citrus limonia. A two-phase solvent system composed of hexane/ethanol/acetonitrile/water (10:8:1:1, v/v) was used for the high-speed counter-current chromatographic isolation of xanthyletin with high yield and over 99% purity as determined by liquid and gas chromatography with mass spectrometry detection. Identifications were performed by UV spectra, IR spectra, (1)H NMR and (13)C NMR.

High-speed counter-current chromatographic isolation of ricinine, an insecticide from Ricinus communis.

The alkaloid ricinine, an insecticide for leaf-cutting ant (Atta sexdens rubropilosa), was obtained from Ricinus communis. A two-phase solvent system composed of CH(2)Cl(2)/EtOH/H(2)O (93:35:72, v/v/v) was used for high-speed counter-current chromatographic (HSCCC) isolation of ricinine in high yield and with over 96% purity, as determined by liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS). Identification of ricinine was performed by comparison of (1)H NMR, (13)C NMR and LC-MS/MS data.

Application of high-performance liquid chromatography-nuclear magnetic resonance coupling to the identification of limonoids from mahogany tree (Switenia macrophylla, Meliaceae) by stopped-flow 1D and 2D NMR spectroscopy.

Separation and characterization of limonoids from Switenia macrophylla (Meliaceae) by HPLC-NMR technique has been described. Analyses were carried out using reversed-phase gradient HPLC elution coupled to NMR (600 MHz) spectrometer in stopped-flow mode. Separated peaks were collected into an interface unit prior to NMR measurements, which were performed with suppression of solvent signals by shaped pulses sequences.

Activity of Ricinus communis (Euphorbiaceae) and ricinine against the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae) and the symbiotic fungus Leucoagaricus gongylophorus.

The focus of this study was the identification of compounds from plant extracts for use in crop protection. This paper reports on the toxic activity of fractions of leaf extracts of Ricinus communis L (Euphorbiaceae) and isolated active compounds in the leaf-cutting ant Atta sexdens rubropilosa Forel and its symbiotic fungus Leucoagaricus gongylophorus (Singer) Möller. The main compounds responsible for activity against the fungus and ant in leaf extracts of R communis were found to be fatty acids for the former and ricinine for the ants.

Structure-activity relationships of novel inhibitors of glyceraldehyde-3-phosphate dehydrogenase.

3D QSAR studies were performed on a library of 120 GAPDH inhibitors, including a series of coumarins, flavonoids, and nucleosides. The VolSurf method was successfully used to calculate surface descriptors for protein-ligand affinity and binding site of the enzyme. PCA/PLS analyses have permitted the evaluation of the structural features crucial for potency, selectivity, and favorable pharmacokinetic properties, and are important for the design of new ligands.