ABSTRACT
The apple is a food rich in diverse classes of polyphenols (PP), among which the proanthocyanidins (PCs), which are primarily concentrated in the skin, are one of the most abundant. These compounds are of considerable interest for their possible positive health effects because of their antioxidant properties. However, depending on the classes of PP present (chemical composition) and their relative concentrations in the apple skin, their antioxidant effects vary and some of their components can even generate prooxidant effects. This work determined the chemical composition and antioxidant-prooxidant potential of a polyphenolic extract (PPE) and a proanthocyanidin-rich fraction (PRF) of apple skin, along with the contribution of their most abundant individual compounds, based on their copper chelating ability, ease in reducing peroxidase-generated free radicals and TEAC (Trolox-Equivalent Antioxidant Capacity) assay. For this purpose, chromatographic and colorimetric methods were used. The majority compounds identified in PPE were flavan-3-ols (44.58%), flavonols (42.89%) and dihydrochalcones (11.60%). In PRF, we detected monomers and oligomers from dimers to heptamers, which were composed of 97% (-)-epicatechin and 3% (+)-catechin. The antioxidant potential was notably higher in PRF than in PPE. The (-)-epicatechin monomer and the procyanidin B2 dimer showed more ease in reducing peroxidase-generated free radicals compared to other compounds of the apple skin, whereas phloridzin dihydrochalcone produced prooxidant effects.
ABSTRACT
This study aimed to quantify the accumulation and elimination of Enrofloxacin (ENRO) and Ciprofloxacin (CIPRO) in cultivated Litopenaeus vannamei under controlled laboratory and farm conditions. Laboratory- and farm-raised shrimp were given feed supplemented with 200 mg/kg ENRO for 14 days, followed by a 16-day diet without antibiotics. The levels of ENRO and CIPRO were analyzed by High Performance Liquid Chromatography (HPLC). In the laboratory, ENRO concentrations in the muscle and hepatopancreas reached a maximum (C(max)) of 0.54 ± 0.26 µg/g and 3.52 ± 1.9 µg/g, respectively; C(max) values for CIPRO in the laboratory were 0.18 ± 0.13 µg/g (muscle) and 1.05 ± 0.20 µg/g (hepatopancreas). In farmed shrimp, C(max) values for ENRO were 0.36 ± 0.17 µg/g muscle and 1.60 ± 0.82 µg/g in the hepatopancreas; CIPRO C(max) values were 0.03 ± 0.02 µg/g (muscle) and 0.36 ± 0.08 µg/g (hepatopancreas). Two to fourteen days were necessary to eliminate both antibiotics from muscular tissue and four to more fourteen days for complete elimination of the antibiotics from the hepatopancreas. These results should be considered in terms of minimum concentrations necessary to inhibit Vibrio bacteria to determine whether the current use of this antibiotic is effective in controlling disease.
ABSTRACT
An efficient multiresidue method for analysis of fluoroquinolones in shrimp has been developed in which quantitation by fluorescence and confirmation by Multiple Stage Mass Spectrometry (MS) is achieved simultaneously. In this method, shrimp tissue is extracted with ammoniacal acetonitrile and the extract is defatted and then evaporated. After dissolution in basic phosphate buffer, fluoroquinolones in the extract are separated by liquid chromatography and quantitated, taking advantage of their intense fluorescence. Eluate from the fluorescence detector enters the MS, which allows for confirmation by monitoring ratios of 2 prominent product ions in the MS3 or MS2 spectrum. Using this method, 8 fluoroquinolones have been analyzed in shrimp samples fortified at 10, 25, 50, or 100 ppb levels. Recoveries for desethyleneciprofloxacin, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, orbifloxacin, sarafloxacin, and difloxacin ranged from 75 to 92%, with relative standard deviation values of <6%. The limits of quantitation ranged from 0.1 to 1 ng/g. Enrofloxacin and ciprofloxacin were also successfully determined in enrofloxacin-incurred shrimp using this method.
