Analysis of isoflavones and flavonoids in human urine by UHPLC

A rapid, ultra high-performance liquid chromatographic (UHPLC) method has been developed and validated for simultaneous identification and analysis of the isoflavones genistein, daidzein, glycitin, puerarin, and biochanin A, and the flavonoids (±)-catechin, (−)-epicatechin, rutin, hesperidin, neohesperidin, quercitrin, and hesperetin in human urine. Urine samples were incubated with β-glucuronidase/sulfatase. UHPLC was performed with a Hypersil Gold (50 × 2.1 mm, 1.9 μm) analytical column. Elution was with a gradient prepared from aqueous trifluoroacetic acid (0.05%) and acetonitrile. UV detection was performed at 254 and 280 nm. The calibration curves were indicative of good linearity (r2 ≥ 0.9992) in the range of interest for each analyte. LODs ranged between 15.4 and 107.0 ng mL−1 and 3.9 and 20.4 ng mL−1 for flavonoids and isoflavones, respectively. Intra-day and inter-day precision (C.V., %) was less than 3.9% and 3.8%, respectively, and accuracy was between 0.03% and 5.0%. Recovery was 70.35–96.58%. The method is very rapid, simple, and reliable, and suitable for pharmacokinetic analysis. It can be routinely used for simultaneous determination of these five isoflavones and seven flavonoids in human urine. The method can also be applied to studies after administration of pharmaceutical preparations containing isoflavones and flavonoids to humans

Toxicological aspects of the use of phenolic compounds in disease prevention

The consumption of a diet low in fat and enhanced by fruits and vegetables, especially rich in phenolic compounds, may reduce risks of many civilization diseases. The use of traditional medicines, mainly derived from plant sources, has become an attractive segment in the management of many lifestyle diseases. Concerning the application of dietary supplements (based on phenolic compounds) in common practice, the ongoing debate over possible adverse effects of certain nutrients and dosage levels is of great importance. Since dietary supplements are not classified as drugs, their potential toxicities and interactions have not been thoroughly evaluated. First, this review will introduce phenolic compounds as natural substances beneficial for human health. Second, the potential dual mode of action of flavonoids will be outlined. Third, potential deleterious impacts of phenolic compounds utilization will be discussed: pro-oxidant and estrogenic activities, cancerogenic potential, cytotoxic effects, apoptosis induction and flavonoid-drug interaction. Finally, future trends within the research field will be indicated

Hyphenated technique for the extraction and determination of isoflavones in algae: Ultrasound-assisted supercritical fluid extraction followed by fast chromatography with tandem mass spectrometry

New hyphenated technique for the extraction and determination of isoflavones in sea and freshwater algae and cyanobacteria was developed. The method consists of sonication sample pretreatment, extraction by supercritical CO2 modified by 3% (v/v) of MeOH/H2O mixture (9:1, v/v) at 35MPa and 40°C for 60min, fast chromatography analysis by the means of Agilent 1200 Series Rapid Resolution and MS/MS determination. Agilent 1200 Series RRLC was used with Zorbax SB-CN chromatographic column (100mm×2.1mm, particle size 3.5μm), 3μl injection volume, mobile phase consisting of 0.2% (v/v) acetic acid in water (solvent A) and acetonitrile (solvent B) and used with linear gradient (30% B at 0min, from 0min to 3min up to 50% B, from 3 to 6min up to 80% B and from 6 to 10min down to 30% B). The flow-rate was 0.4mL/min, column oven temperature 35°C. MS detector Agilent Technologies 6460 Triple quadrupole LC/MS with Agilent Jet Stream was used in a negative ESI mode under following conditions: gas temperature 350°C, gas flow 13L/min, nebulizer gas pressure 50psi, sheath gas temperature 400°C, sheath gas flow 12L/min, capillary voltage was 4kV. Samples were analysed in the multiple reaction monitoring (MRM) mode. Eight isoflavone compounds were found for the first time in seven real samples of sea algae and in three control samples of freshwater algae and cyanobacteria. Usual optimisation study of extraction parameters was performed. Pressure and temperature optima for algae matrix are different from those obtained sooner for other matrices for most of the analytes, but the results of modifier optimisation study are in good accordance with those obtained sooner for spiked samples and red clover matrix. It seems that matrix has very small or no effect on the modifier selection. Two different approaches of sonication pretreatment were tested: sonication bath and the thorn instrument. In longer extraction time experiments, thorn sonication was more efficient and recovery of following supercritical fluid extraction was higher. © 2010 Elsevier B.V.Peer Reviewe

Assessment of antioxidants by HPLC-MS in grapevine seeds

It is well known, that grapevine seeds are rich in significant antioxidants. However, the issue of dealing with the analysis and comparison of antioxidant components in the seeds of Vitis vinifera L. in individual cultivars has not yet been sufficiently studied. The experiment was performed with extracts of three varieties (Blaufränkish, Italian Riesling and Cabernet Moravia) and three interspecific cultivars (Nativa, Marlen and Kofranka). Contents of nine major flavonoids (apigenin, astragalin, hyperoside, isorhamnetin, kaempferol, myricetin, quercetin, quercitrin and rutin) and two procyanidins (procyanidin A2 and procyanidin B1) were assessed by the HPLC/MS method. The highest contents of antioxidants were found out in interspecific cultivars Marlen and Nativa while the lowest one was assessed in the cultivar Cabernet Moravia. The most represented flavonoid was hyperoside (cultivar Marlen – 15.66 mg∙l–1), least represented was kaempferol (cultivar Cabernet Moravia – 1.81 µg∙l–1)

Nanoparticles of cerium, iron, and silicon oxides change the metabolism of phenols and flavonoids in butterhead lettuce and sweet pepper seedlings

The aim of the study was to determine the effects of CeO2, Fe2 O3, and SiO2 nanoparticles on the metabolism of phenols and flavonoids and the antioxidant status of butterhead lettuce and sweet pepper seedlings. Nanoparticles were used as a 1.5% suspension on the leaves. Phenolic and flavonoid contents increased as well as the antioxidant capacity of sweet pepper after exposure to Fe2O3-NPs. Phenolic and flavonoid concentrations in lettuce were the highest when CeO2-NPs were applied, while glutathione content increased due to Fe2O3-NPs and CeO2-NPs treatment. The highest ascorbic acid concentration was found in sweet pepper exposed to CeO2-NPs. The levels of dehydroascorbic acid, monodehydroascorbate, and L-galactono-1,4-lactone were the highest as a result of foliar spraying of sweet pepper with SiO2-NPs, but the ascorbic acid content in that plant was the lowest. Carotenoids increased after spraying of lettuce with SiO2-NPs. Individual metabolites from phenolic and flavonoid metabolism were determined. In lettuce seedlings, five phenolic compounds were decreased (3,4-diOH-benzaldehyde, ferulic acid, p-coumaric acid, salicylic acid, and vanillin) and two compounds (gallic acid and vanillic acid) were increased in comparison to control plants, while for sweet pepper an increase was observed for four compounds (chlorogenic acid, neochlorogenic acid, ferulic acid, and protocatechuic acid). To the best of our knowledge, this is the first study on the phenolic profile of edible juvenile plants treated with suchmetal/metalloid nanoparticles. We may also conclude that various nanoparticles may interact differently with phenolic phytochemicals depending also on plant species that have varying levels of stress tolerance