Direct conversion of polyconjugated compounds into their corresponding carboxylic acids by Acetobacter aceti

The conversion of polyconjugated aldehydes or alcohols into their corresponding acids was carried out using Acetobacter aceti. The analytical results were compared with those of the acids chemically obtained using a Horner-Wittig reaction

Plumage carotenoids of the Pin-tailed Manakin (Ilicura militaris) : evidence for the endogenous production of rhodoxanthin from a colour variant

The Pin-tailed Manakin (Ilicura militaris) is a small, sexually dimorphic, frugivorous suboscine songbird (Pipridae; Passeriformes; Aves) endemic to the Atlantic Forest of Brazil. A variant individual of this species was recently described in which the red patches that characterise the male's Definitive plumage were replaced by orange-yellow ones. We show here that the pigments in the feathers of the colour variant are common dietary carotenoids (zeaxanthin, \u3b2-cryptoxanthin), not carotenoids synthesised by birds, lending support to the suggestion that the individual is a colour mutant lacking the capability to transform yellow dietary pigments into the red pigments normally present in these feathers. By comparison, the yellow crown feathers of a close relative, the Golden-winged Manakin (Masius chrysopterus), contained predominantly endogenously produced \u3b5-caroten-3\u2032-ones. Surprisingly, the normal-coloured feathers of the male Pin-tailed Manakin owe their red hue to rhodoxanthin, an unusual carotenoid more commonly found in plants, rather than 4-keto-carotenoids typically found in red plumages and found lacking in previously characterised bird colour variants. The implication is that birds, like the tilapia fish, may be able to synthesise this unusual pigment endogenously from dietary precursors. A newly described carotenoid, 6-hydroxy-\u3b5,\u3b5-carotene-3,3\u2032-dione, here named piprixanthin, present in the red feathers of the Pin-tailed Manakin, provides a plausible intermediate between \u3b5,\u3b5-carotene-3,3\u2032-dione (canary-xanthophyll B), a bright yellow pigment found in this and other songbirds, and rhodoxanthin. It is apparent that pigeons (Columbidae, Columbiformes) also have the capability to produce rhodoxanthin, and a structurally related pigment, endogenously. The ability to synthesise rhodoxanthin might have arisen at least twice in birds

Preparation and Characterization of Aminated Carbon from a Single-Step Reaction

The paper describes a single-step procedure by which linear terminal diamines are directly anchored onto activated carbon in sizable amounts ( 5%). Evidence for the formation of real amide bonds is provided by using a range of spectroscopic and \u201cin situ\u201d electrochemical determinations (X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller, Fourier transform infrared, Boehm titrations, and potentiometric acid-base titrations). Results on the reaction stoichiometry are also given, showing that diamines and surface carboxyls react in a close to 1:1 molar ratio. Terminal -NH2 groups not engaged in amide bonds are free to react further and, in the present conditions, show well-defined proton adsorption behavior

Quantitative determination of amorphous cyclosporine in crystalline cyclosporine samples by Fourier transform infrared spectroscopy

The purpose of this study is the development of a quantification method to detect the amount of amorphous cyclosporine using Fourier transform infrared (FTIR) spectroscopy. The mixing of different percentages of crystalline cyclosporine with amorphous cyclosporine was used to obtain a set of standards, composed of cyclosporine samples characterized by different percentages of amorphous cyclosporine. Using a wavelength range of 450-4,000 cm(-1), FTIR spectra were obtained from samples in potassium bromide pellets and then a partial least squares (PLS) model was exploited to correlate the features of the FTIR spectra with the percentage of amorphous cyclosporine in the samples. This model gave a standard error of estimate (SEE) of 0.3562, with an r value of 0.9971 and a standard error of prediction (SEP) of 0.4168, which derives from the cross validation function used to check the precision of the model. Statistical values reveal the applicability of the method to the quantitative determination of amorphous cyclosporine in crystalline cyclosporine samples

Structural Analysis of Fagopyrin Extracts by HPLC-MS, NMR and CD

Fagopyrin is a phenantro-perylenequinone present in the flowers of Fagopyrum aesculentum (buckwheat), endowed with photodynamic activity and responsible of a certain number of photosensitizing syndromes in grazing animals (fagopyrism)1. This molecule was firstly extracted, more than 30 years ago, by Brockmann, who ascertained its chemical constitution.2 More accurate structural investigations, performed on the related compound hypericin, showed that a high degree of structural and conformational complexity might be present,3 as the aromatic system is involved in different equilibria of tautomerism, dissociation, torsional isomerism, and homoassociation. In the case of fagopyrin, the presence of two piperidine rings at positions 2 and 5 introduces two new stereogenic centres, in addition to the axial chirality of the aromatic system. Apart from the fundamental work of Brockmann, who did not establish the absolute configuration of the isolated fagopyrin, no other study has appeared, reporting a detailed analysis of the various stereogenic centres. Here, we wish to report our results regarding the stereochemistry of fagopyrin, as well as the composition of fagopyrin extracts; which actually proved to be complex mixtures of up to twenty molecules. Some of them are constituted by the same perylene-quinone, linked not only to piperidine, but also to pirrolidine moieties. This generates three different groups of closely related molecules (see Figure), depending on the nature of the linked heterocycles, with the generation of up to 8 stereoisomers within each family. The configuration of each stereocenter has been established by NMR and CD measurements, combined with ab-initio calculations (Gaussian03). Finally, the highly acidic hydroxyl groups allow the formation of zwitterionic species constituted by ion-pairs between the protonated amino groups and the negatively charged hypericinate ion. 1. Wender S. H., Gortner R. A., Inman O. L., J. Am. Chem. Soc., 1943, 65, 1733-1735. 2. Brockmann H., Lackner H., Tetrahedron Lett., 1979, 1575-1578. 3. Falk H., Angew. Chem. Int. Ed., 1999, 38, 3116-3136

Complete characterization of extracts of Onopordum illyricum L (Asteraceae) by HPLC/PDA/ESIMS and NMR

The aerial parts of Onopordum illyricum L. (Asteraceae) are eaten raw in salad in the Mediterranean area, representing a food of good nutritional value. Extracts of different parts of this plant have been analyzed by HPLC/DAD/ESIMS and the major compounds identified by NMR spectroscopy. Fatty acids, sesquiterpene lactones, triterpenes and polyphenols (flavones and caffeoyl quinic acids) fully describe the plant metabolism during the vegetation year. All the metabolites are non toxic nutrients, and are reported in the literature to possess biological activities positive for health, confirming the beneficial use in the diet of this thistl

Host-guest interaction study of resveratrol with natural and modified cyclodextrins

The aim of this work is to increase the stability and water soly. of resveratrol by complexation with different cyclodextrins. Furthermore, phys.-chem. properties of each inclusion compd. were investigated. Complexes of resveratrol with cyclodextrins both native (a, b, g) and modified (2-hydroxypropyl-b-cyclodextrin, dimethyl-b-cyclodextrin) were obtained by using the suspension method. An inclusion complex with b-cyclodextrin was also prepd. by using the microwave. Solid state characterization of the products was carried out using Fourier transform IR spectroscopy (FT-IR), differential scanning calorimetry (DSC), x-ray diffraction (DRX); soln. studies were performed by UV-Vis spectrophotometry and 1H-NMR spectroscopy. Phase soly. profiles with all cyclodextrins employed were classified as AN type, indicating the formation of 1:1 stoichiometric inclusion complexes. Stability consts. (Kc) from the phase soly. diagrams were calcd. Stability studies in the solid state and in soln. were performed; the photodegrdn. by UV-Vis spectrophotometry was monitored. The isomerization rate trans to cis, in ethanol soln., decreased with inclusion. The dissoln. studies revealed that resveratrol dissoln. rate was improved by the formation of inclusion complexe

Complete Characterization of Extracts of Onopordum illyricum L.(Asteraceae) by HPLC/PDA/ESIMS and NMR

The aerial parts of Onopordum illyricum L. (Asteraceae) are eaten raw in salad in the Mediterranean area, representing a food of good nutritional value. Extracts of different parts of this plant have been analyzed by HPLC/DAD/ESIMS and the major compounds identified by NMR spectroscopy. Fatty acids, sesquiterpene lactones, triterpenes and polyphenols (flavones and caffeoyl quinic acids) fully describe the plant metabolism during the vegetation year. All the metabolites are non toxic nutrients, and are reported in the literature to possess biological activities positive for health, confirming the beneficial use in the diet of this thistl