Renata Colombo

Study of C- and O-glycosylflavones in sugarcane extracts using liquid chromatography: exact mass measurement mass spectrometry

The flavonoids present in sugarcane (Saccharum officinarum) extracts were analyzed by liquid chromatography - mass spectrometry (LC-MS), and a study of the fragmentation patterns of selected flavonoids was conducted using orthogonal acceleration time-of-flight electrospray ionization mass spectrometry (ESI-oa-ToF MS). Seven C- and O-glycosylflavones were identified in the extracts, namely, schaftoside, isoschaftoside, luteolin-8-C-(rhamnosylglucoside), vitexin, orientin, tricin-7-O-neohesperidoside and tricin-7-O-glucoside. Of these, five were identified in the absence of direct comparison with their respective standards. The described method also permitted the differentiation of the 6-C and 8-C isomeric flavones, schaftoside and isoschaftoside. The combination of fragmentation data and exact mass measurement showed to be complimentary to the HPLC-UV-MS techniques previously utilized for isomers discrimination in sugarcane studies.

Voxelwise evaluation of white matter volumes in first-episode psychosis

The occurrence of white matter (WM) abnormalities in psychotic disorders has been suggested by several studies investigating brain pathology and diffusion tensor measures, but evidence assessing regional WM morphometry is still scarce and conflicting. In the present study, 122 individuals with first-episode psychosis (FEP) (62 fulfilling criteria for schizophrenia/schizophreniform disorder, 26 psychotic bipolar I disorder, and 20 psychotic major depressive disorder) underwent magnetic resonance imaging, as well as 94 epidemiologically recruited controls. Images were processed with the Statistical Parametric Mapping (SPM2) package, and voxel-based morphometry was used to compare groups (t-test) and subgroups (ANOVA). Initially, no regional WM abnormalities were observed when both groups (overall FEP group versus controls) and subgroups (i.e., schizophrenia/schizophreniform, psychotic bipolar I disorder, psychotic depression, and controls) were compared. However, when the voxelwise analyses were repeated excluding subjects with comorbid substance abuse or dependence, the resulting statistical maps revealed a focal volumetric reduction in right frontal WM, corresponding to the right middle frontal gyral WM/third subcomponent of the superior longitudinal fasciculus, in subjects with schizophrenia/schizophreniform disorder (n=40) relative to controls (n=89). Our results suggest that schizophrenia/schizophreniform disorder is associated with right frontal WM volume decrease at an early course of the illness.

On-line identification of minor flavones from sugarcane juice by LC/UV/MS and post-column derivatization

Este trabalho apresenta a identificacao “on line” de flavonas minoritarias do suco da cana-deacucar (Saccharum officinarum) , por cromatografia liquida de alta eficiencia com detector UV acoplada a espectrometria de massas (CL/UV/EM) com ionizacao quimica a pressao atmosferica, dissociacao induzida por colisao (IQPA-DIC-EM/EM) e derivatizacao pos-coluna utilizando reagentes de deslocamento de UV. As analises CLAE-UV com reagentes de deslocamento forneceram informacoes sobre a posicao da substituicao no esqueleto dos flavonoides e, em combinacao com dados de EM, estas tecnicas permitiram a identificacao “on-line” de cinco flavonas da garapa: luteolina-8- C-glucosil-7-O-glucuronideo; tricina-7-O-neoesperosideo-4’O-ramnosideo; tricina-7-O-metilglucuronato-4’-O-ramnosideo; tricina-7-O-metilglucuronideo; swertisina; e outras quatro substâncias foram parcialmente identificadas como flavonas glicosiladas. Somente a swertisina (7-O-metilapigenina-6-C-glicosideo) foi anteriormente descrita no bagaco da cana-de-acucar. This work describes the on-line characterization of minor flavones from sugarcane (Saccharum officinarum ) juice by high-performance liquid chromatography coupled to diode array UV detection and mass spectrometry (LC/UV/MS) using atmospheric pressure chemical ionizationcollision-induced dissociation (APCI-CID-MS/MS) and post-column derivatization using UV shift reagents. HPLC-UV analysis with shift reagents provided information about the substitution pattern in the flavonoid skeleton and, combined with MS data, these techniques allowed for the on-line identification of five “garapa” flavones: luteolin-8- C-glucosyl-7-O-glucuronide; tricin-7-O-neohesperoside-4’-O-rhamnoside; tricin-7-O-methylglucuronate-4’-O-rhamnoside; tricin-7-O-methylglucuronide; swertisin, while four other compounds were partially identified as glycosylflavones. Only swertisin (7- O-methylapigenin-6-C-glucoside) was reported previously in sugarcane molasses.

Photo-Fenton degradation of the insecticide esfenvalerate in aqueous medium using a recirculation flow-through UV photoreactor

The aim of the study was to evaluate the efficiencies of photo-Fenton (Fe(2+)) and (Fe(3+)) processes in the degradation of high-concentrations of esfenvalerate (in the form of aqueous emulsion of a commercial formulation) using a recirculation flow-through photoreactor irradiated with UV light from a 15 W lamp (254 nm emission peak). The results obtained using a basic photo-Fenton (Fe(2+)) reaction (esfenvalerate 17 mg L(-1); ferrous sulphate 1 mM; hydrogen peroxide 25 mM; pH 2.5) were compared with those acquired when ferrioxalate (1, 3 or 5 mM) served as the iron source. Degradation of the active component of the commercial formulation was significantly greater, and the rate of oxidation more rapid, using a photo-Fenton (Fe(3+)) process compared with its Fe(2+) counterpart. The most efficient degradation of the insecticide (75% in 180 min) was achieved with a reaction mixture containing 5mM ferrioxalate. However, under the same experimental conditions, degradation of pure esfenvalerate preceded much faster (99% in 60 min) and was 100% complete within 180 min reaction time.

Multivariate analysis of the effects of soil parameters and environmental factors on the flavonoid content of leaves of Passiflora incarnata L., Passifloraceae

The aim of the present study was to evaluate the effect of soil characteristics (pH, macro- and micro-nutrients), environmental factors (temperature, humidity, period of the year and time of day of collection) and meteorological conditions (rain, sun, cloud and cloud/rain) on the flavonoid content of leaves of Passiflora incarnata L., Passifloraceae. The total flavonoid contents of leaf samples harvested from plants cultivated or collected under different conditions were quantified by high-performance liquid chromatography with ultraviolet detection (HPLC-UV/PAD). Chemometric treatment of the data by principal component (PCA) and hierarchic cluster analyses (HCA) showed that the samples did not present a specific classification in relation to the environmental and soil variables studied, and that the environmental variables were not significant in describing the data set. However, the levels of the elements Fe, B and Cu present in the soil showed an inverse correlation with the total flavonoid contents of the leaves of P. incarnata.

LC-MS/MS ANALYSIS OF SUGARCANE EXTRACTS AND DIFFERENTIATION OF MONOSACCHARIDES MOIETIES OF FLAVONE C-GLYCOSIDES

LC-MS/MS data of the flavones from extracts of nonmodified and transgenic sugarcane (“Bowman-Birk” and “Kunitz”) led to the proposition of characteristic fragmentations that can be applied to identify the monosaccharides glucose, arabinose, and rhamnose in C-glycosylflavones. Collision-induced dissociation (CID) MS/MS generated diagnostic ions for different linked sugars in C-glycosylflavone–O-glycoside and C-glycosylflavone–O-acid derivatives, and the combination of MS data with postcolumn derivatization using UV shift reagents (which provide complementary information to determine the substitution patterns in the flavone skeleton) allowed for the identification of seven flavones not previously reported in sugarcane: 6-methoxyluteolin-8-C-arabinosyl-7-O-glucoside; diosmetin-8-C-arabinosyl-7-O-arabinoside; vitexin-7-O-rhamnoside; diosmetin-8-C-rhamnosyl-7-O-glucoside; tricetin-8–C-(6‴-O-sinapoylglucoside); 7,4′ di-O-methylapigenin-8-C-arabinosyl-rhamnoside; and luteolin-8-C-rhamnosyl-7-O-rhamnoside.

CZE/PAD and HPLC-UV/PAD Profile of Flavonoids from Maytenus aquifolium and Maytenus ilicifolia “espinheira santa” Leaves Extracts

This paper describes the application of HPLC and CZE to analyze flavonoids in the leaves of Maytenus ilicifolia and Maytenus aquifolium, which are species widely used in Brazilian folk medicine. The two species showed different flavonoid profiles, but acidic hydrolysis of the Maytenus extracts confirmed that all these compounds are quercetin or kaempferol derivatives. A comparison of the CZE and HPLC profiles of Maytenus extracts showed numerous flavonoid peaks using HPLC. However, the advantages of CZE such as analysis without requiring clean-up and less generation of chemical waste than with HPLC point to the potential of the CZE technique for the quality control (routine analysis) of “espinheira santa” phytopharmaceuticals.

Análise dos produtos de degradação do esfenvalerato por SBSE/CLAE-UV/DAD utilizando planejamento fatorial fracionário

A simple procedure based on stir bar sorptive extraction and high-performance liquid chromatography-ultraviolet/photodiode array detection (SBSE/LC-UV/PAD) to determine intermediates and by-products of esfenvalerate is described. The influence of organic modifier, ionic strength, extraction time, temperature and pH were simultaneously evaluated by using a factorial experimental design. The utilization of different organic solvents and desorption times were also investigated to establish the optimal conditions for SBSE liquid desorption. Among the ten different peaks (intermediates and by-products) detected after degradation of esfenvalerate, eight (including 3-phenoxybenzoic acid and 3-phenoxybenzaldehyde) were successfully extracted by SBSE under the optimized conditions.

Degradation Products of Lambda-Cyhalothrin in Aqueous Solution as Determined by SBSE-GC-IT-MS

Lambda-cyhalothrin is a widely employed pyrethroid insecticide and is potentially toxic to the environment and to human health. Several reports indicate the presence of this insecticide in water samples worldwide, but more data about its behavior in waters and its derivative products are required. This study shows the behavior of the pesticide lambda-cyhalothrin in aqueous solution at different pH and temperature that were simulated by using water contaminated with a toxic concentration of lambda-cyhalothrin and chemical oxidative process. Lambda-cyhalothrin and its derivative products were monitored employing stir bar sorptive extraction (SBSE), using liquid and thermal desorption, combined with gas chromatography coupled with ion trap mass spectrometry (GC-IT-MS) technology. GC-IT-MS enabled the proposal of the lambda-cyhalothrin chemical transformation pathway and the full identification of twelve derivative products. Among them, only 3-phenoxybenzaldehyde is reported as a degradation product of lambda-cyhalothrin, and this compound is an environmental pollutant with endocrine disrupting activity.

Screening of By-Products of Esfenvalerate in Aqueous Medium Using SBSE Probe Desorption GC-IT-MS Technique

The pyrethroids, their metabolites and by-products have been recognized as toxic to environment and human health. Despite several studies about esfenvalerate toxicity and its detection in water and sediments, information about its degradation products is still scanty. In this work, esfenvalerate degradation products were obtained by chemical oxidation with hydrogen peroxide and their structure was elucidated using a procedure known as stir bar sorptive extraction (SBSE) probe desorption gas chromatography-ion trap mass spectrometry (GC-IT-MS) analysis. This procedure consists of the thermal desorption of analytes extracted from a SBSE stir bar introduced by a probe into a gas chromatograph (GC) coupled to an ion trap mass spectrometry (IT-MS) system. Based on IT-MS data, a degradation pathway of esfenvalerate is proposed with ten products of chemical oxidation of esfenvalerate that are fully identified. Among these compounds, 3-phenoxybenzoic acid and 3-phenoxybenzaldehyde were detected, reported as being environmental metabolites of some pyrethroids, with endocrine-disrupting activity.