Erika Bando

Antibacterial activity of Ocimum gratissimum L. essential oil

The essential oil (EO) of Ocimum gratissimum inhibited Staphylococcus aureus at a concentration of 0.75 mg/ml. The minimal inhibitory concentrations (MICs) for Shigella flexineri, Salmonella enteritidis, Escherichia coli, Klebsiella sp., and Proteus mirabilis were at concentrations ranging from 3 to 12 microg/ml. The endpoint was not reached for Pseudomonas aeruginosa (>=24 mg/ml). The MICs of the reference drugs used in this study were similar to those presented in other reports. The minimum bactericidal concentration of EO was within a twofold dilution of the MIC for this organism. The compound that showed antibacterial activity in the EO of O. gratissimum was identified as eugenol and structural findings were further supported by gas chromatography/mass spectra retention time data. The structure was supported by spectroscopic methods.

Biomarcadores para avaliação da exposição humana às micotoxinas

Currently, mycotoxins represent a risk of environmental contamination, causing serious damages to human health. Those toxins can be found in different kinds of foods, and they constitute the main source of human exposure. The evaluation of such exposures can be monitored through the use of biomarkers, which elucidates the cause/effect and dose/effect relation in the evaluation of health risks for clinical and laboratory diagnostic purposes. The MEDLINE review about the use of biomarkers for assessment of aflatoxins, fumonisins, deoxynivalenol and ochratoxin A was carried out from 1981 to 2005. The biomarkers for assessment of human exposure to aflatoxins were the urinary metabolites of aflatoxin B1: aflatoxin M1, aflatoxin P1, aflatoxin Q1, the free aflatoxin in serum or plasma, the AFB-N7-guanine adducts and the albumin adducts or mutation in the tumour suppressor gene p53 present in human biological fluids. As far as fumonisins are concerned, levels of free fumonisin B1 and fumonisin B2, or levels of sphinganine and sphingosin, were quantified in blood and urine. As exposure biomarkers, deoxynivalenol has its own metabolism products and adducts (protein/DNA) present in human fluids. As to ochratoxin A exposure, we measure it in biological fluids, once it enables us to prevent or minimize the incidence of deaths or illnesses provoked by chemical exposure. Primeira submissao em 05/06/06 Ultima submissao em 22/02/07 Aceito para publicacao em 07/03/07 Publicado em 20/06/07 ARTIGO DE ATUALIZACAO UPDATING ARTICLEAtualmente, as micotoxinas representam um risco de contaminacao ambiental, acarretando serios prejuizos a saude humana. Essas toxinas podem estar presentes em diferentes tipos de alimentos, que constituem a principal fonte de exposicao para o homem. As exposicoes podem ser monitoradas atraves do uso de biomarcadores, que elucidam a relacao causa/efeito e dose/efeito na avaliacao de risco a saude para fins de diagnostico clinico e laboratorial. Realizou-se uma revisao bibliografica do periodo de 1981-2005, no MEDLINE, sobre utilizacao e propostas de biomarcadores para a exposicao a aflatoxinas, fumonisinas, desoxinivalenol e ocratoxina A. Os possiveis biomarcadores para avaliar a exposicao humana as aflatoxinas foram os metabolitos urinarios de aflatoxina B1, como aflatoxina M1, aflatoxina P1, aflatoxina Q1, aflatoxina livre em soro ou plasma, os adutos de AFB-N7-guanina, os adutos de albumina ou mutacao no gene supressor de tumor p53, presentes em fluidos biologicos. Para as fumonisinas, os biomarcadores foram os niveis de fumonisina B1 e fumonisina B2 livres, ou de esfinganina e esfingosina em sangue e urina. O desoxinivalenol tem como biomarcadores de exposicao os produtos de seu metabolismo e adutos macromoleculares (proteina/DNA) presentes nos fluidos biologicos. Para a exposicao a ocratoxina A (OA) os biomarcadores se restringem a quantificacao da propria toxina nos fluidos biologicos. A avaliacao da exposicao as micotoxinas constitui um importante aspecto para a saude publica, tendo em vista a possibilidade de prevenir ou minimizar a incidencia de doencas decorrentes da sua interacao com o organismo.

Oxytetracycline, tetracycline, chlortetracycline and doxycycline in pasteurised cow’s milk commercialised in Brazil

The aim of this study was to investigate the presence of tetracycline residues in pasteurised cow’s milk using high-performance liquid chromatography coupled with UV/VIS detection to determine the exposure of Brazilian’s population to antibiotic residues. One hundred samples collected from the State of Paraná, Brazil, were analysed. Three of these samples were contaminated at the following concentrations: 121.8 µg·kg−1 for oxytetracycline, 93.5 µg·kg−1 for tetracycline and 134.6 µg·kg−1 for chlortetracycline (61.6 µg·kg−1) and doxycycline (73.0 µg·kg−1). The median tetracycline residue concentration found in the samples was 42.3 µg·kg−1, and the estimated daily intake (EDI) was 0.05 µg Kg−1 bw day−1 in Brazil. These results demonstrate that the occurrence of tetracycline in Brazilian milk was low (3%) and only for 2% above the maximum residue limit, so the risk to the population from the presence of these residues in milk was low (<1% of the acceptable daily intake).

Trace metal levels in serum and urine of a population in southern Brazil

This study aimed to evaluate serum and urine concentrations of several trace metals of a non-directly exposed population in southern Brazil and establish reference values. Serum and urine samples were obtained from 240 volunteers (175 males and 65 females, age ranging from 18 to 74 years old). Levels of arsenic, chromium, cobalt, copper, lead, nickel, manganese and zinc were determined by means of dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS). Comparison between genders resulted in no significant difference for all metals but serum copper, as concentrations are higher in females than males. For most metals assessed, a negative correlation between serum concentrations and age was found, but no significant correlation was found between urine concentrations and age.

Occurrence of aflatoxin M1 in bovine milk commercialized in the Parana State, Brazil

The objective of this study was evaluate the presence of AFM1 in 82 samples of pasteurized bovine milk commercialized in 11 municipalities in the State of Parana, Brazil, from March 2010 to May 2011. Analytical methodology used was the enzyme immunoassay to determine qualitatively the presence of AFM1 (detection limit = 0.05 ?g.kg-1). AFM1 was not detected in any sample. The results were satisfactory. However, there is need for monitoring by government agencies, in order to provide safety, quality and integrity for human health.

Intralaboratory optimization and validation of a method for patulin determination in grapes by Thin-Layer Chromatography

The aim of this work was to optimize and validate, by intralaboratorial procedures, a method for the determination of patulin in grapes by thin-layer chromatography. The steps of extraction, cleanup, detection and quantification were optimized. For the validation of the method, recovery assays with standard solutions and artificially contaminated samples were carried out. The mean recovery and the variation coefficient were 65.4% and 7.58%, respectively. The optimized conditions were: 50 mL of grape juice, three extraction stages (with 100 mL of ethyl acetate in the first stage and 50 mL in second and third stages), and 100 µL of ethanol to solubilize the extract. The solvent-system used was toluene - ethyl acetate - formic acid (6:3:1), and 0.5% MBTH in 5% formic acid was sprayed on the plates to intensify the fluorescence. The visual detection and quantification limits were 7.44 ng and 15.87 µg.kg-1, respectively. The optimized and validated method demonstrated sufficient efficiency for adoption in the monitoring of patulin in grape.

Occurrence and risk assessment of population exposed to deoxynivalenol in foods derived from wheat flour in Brazil

ABSTRACT Deoxynivalenol (DON) is the most important of the trichothecenes in terms of amounts and occurrence in wheat. This compound was shown to be associated with a glomerulonephropathy involving an increase of immunoglobulin A in humans. This study assessed the occurrence of DON in wheat flour and the exposure of Brazilian teenagers, adults and elderly to this mycotoxin due to intake of wheat flour-based products. DON extraction in wheat flour was carried out by solid phase extraction and the quantification was performed by ultra-high proficiency liquid chromatography with diode-array detection. A total of 77.9% of all samples were positive for DON, with concentrations ranging from 73.50 to 2794.63 µg kg−1. The intake was calculated for the average and 90th percentile of the contamination levels of DON in foods based-wheat for teenagers, adults and elderly in Brazil, and compared with the provisional maximum tolerable daily intakes (PMTDI). Females of all age groups were exposed to DON at higher levels when compared to males in regard of consumption of breads and pastas. Teenagers were the main consumers of foods derived from wheat flour, with maximum probable daily intakes of 1.28 and 1.20 µg kg−1 b.w. day−1 for females and males, respectively. This population is at an increased risk of exposure to DON due to consumption of wheat flour-based foods in Brazil.