Simultaneous Determination of Phenolic Compounds in Plasma by LC-ESI-MS/MS and Their Bioavailability after the Ingestion of Table Olives

The role attributed to polyphenols on human health needs to be correlated with their plasmatic concentrations after food consumption. Then, a method based on liquid-liquid extraction followed by highly sensitive LC-ESI-MS/MS analysis was developed to determinate 16 phenolic compounds in plasma. Validation gave appropriate recovery, matrix effect (80%-120%), linear correlation (R² > 0.995), precision (<15%), LOQ (0.04-2.51 nM), and short chromatographic run. The method was verified after the administration of Arbequina table olives to rats. A single dose of destoned olives was given by gavage, and plasmatic concentrations of polyphenols were analyzed at 30 min. Interestingly, the profile found in plasma greatly differed from that of the olives. Plasmatic concentrations, from highest to lowest, were salidroside, p-coumaric acid, hydroxytyrosol, verbascoside, tyrosol, luteolin, and luteolin-7-O-glucoside. In conclusion, a simple and robust method was developed, enabling the identification and quantification of unaltered polyphenols in plasma after olives consumption, thus demonstrating its suitability for pharmacokinetics studies.

Effect of Lactobacillus Rhamnosus on serum uremic toxins (phenol and P-Cresol) in hemodialysis patients: A double blind randomized clinical trial

BACKGROUND

Uremic toxins such as p-cresol and phenol are suggested to be associated with higher mortality in hemodialysis patients. The aim of this study was to investigate the effects of probiotics on some serum uremic toxin levels in hemodialysis patients.

METHODS

Patients undergoing hemodialysis in a university dialysis center were enrolled in this randomized controlled double blind clinical trial. The patients received probiotic (Lactobacillus Rhamnosus) for duration of 4 weeks. All data were presented as the mean ± SD. Statistical analyses were performed by SPSS statistical software. Paired t-test was used to compare pre- and post-treatment p-cresol levels. P values less than .05 were considered statistically significant.

RESULTS

A total of 42 hemodialysis patients (32 male and 10 female) were enrolled in this study. The mean ± SD age of the patients in Lactobacillus Rhamnosus and placebo groups were 57.05 ± 13.96 and 59.67 ± 15.04 years, respectively. Values of uremic toxins before treatment did not differ statistically between groups but they were significantly lower in Lactobacillus Rhamnosus group compared with placebo group (P < .05). Total Phenol and p-cresol levels were associated with sodium, energy, carbohydrate, fat and protein intake and fiber consumption, accompanying by hemodialysis hours per week in linear regression analyses.

CONCLUSIONS

This study demonstrated that probiotics could be a promising target in hemodialysis patients with the capability of decreasing serum phenolic uremic toxins in this population.

TRIAL REGISTRATION

IRCT20154182017N21 Date:09/12/2016.

[Clinical and laboratory diagnostic criteria of chronic glomerular and tubulointerstitial kidney disorders associated with exposure to metals and oxygen organic compounds of technogenic origin]

Complex clinical, functional an laboratory examination of children living under unacceptable risk conditions due to aerogenous exposure to cadmium, chromium, lead and phenol revealed that kidney diseases associated with exposure to metals and phenol develop in children with genetic predisposition to disordered biotransformation of chemicals--polymorphism of genes CYPOX, RCYT 450, SULTA1 in homozygous and heterozygous variants. Increased levels of chemicals in blood causes microcirculation disorders in renal cortex, direct toxic effect in nephrons, suppresses activity of anitoxidant defense on cellular and systemic levels. The authors specified pathogenetically based complex of clinical and laboratory diagnostic markers of chronic kidney diseases associated with exposure to metals (cadmium, chromium, lead) and oxygen-containing (phenol) organic compounds.

[Substantiating the blood concentrations of phenol and alkylphenols (o-, m-, and p-cresols) providing the acceptable risk to human health]

The paper considers the current nontraditional approaches to revealing the causal effects and criteria for significance of an exposure-response relationship. The study has used the elements of methodology for assessing the risk and the techniques of environmental epidemiology to examine causal effects. A blood toxicant-response marker relationship was assessed and the quantitative characteristics of the association between the concentrations of the test compounds and the risk of noxious effects were ascertained. On the basis of exposure marker-response marker models, the authors revealed the priority types of functional changes and established the blood concentrations of phenol and m- and n-cresols at an acceptable risk level.

Dietary galacto-oligosaccharides mixture can suppress serum phenol and p-cresol levels in rats fed tyrosine diet

Phenols (phenol and p-cresol) are amino acid metabolites produced by intestinal bacteria. Some reports have demonstrated that the accumulation of phenols in the serum has toxic effects in renal failure patients. In this study, we found that phenols accumulated in the serum of rats given a tyrosine diet, and that dietary intake of a galacto-oligosaccharide mixture (GOS) suppressed the accumulation of phenols in serum. Rats were fed a basal diet, tyrosine diet (basal diet with 2.5% tyrosine) or GOS diet (tyrosine diet with 5% GOS) for 2 wk. The concentrations of phenols in the feces, cecal contents, serum and urine were determined. Concentrations of phenols in the serum, cecal contents and feces from rats fed the tyrosine diet were significantly higher than those in rats fed the basal diet. The concentrations of phenols in feces, cecal contents and serum, and urinary excretion in the GOS diet group were significantly lower than those in the tyrosine diet group. The pH of cecal contents was decreased by GOS intake. Furthermore, the serum concentrations of phenols were closely correlated with cecal concentrations. This finding suggested that concentrations of phenols in the serum reflected phenol production in the cecum contents. These results showed that dietary intake of GOS could modify the intestinal environment, and suppress the production of phenols in the intestinal tract and the accumulation of phenols in the serum. Thus, GOS may help improve the quality of life (QOL) of patients with renal failure.

Bioavailability and efficiency of rutin as an antioxidant: a human supplementation study

OBJECTIVE

To determine the potential antioxidant effect of rutin (quercetin-3-O-beta-rutinoside) supplementation.

DESIGN

A 6-week randomized single-blind placebo controlled trial was conducted; 500 mg rutin supplement was compared to an equivalent amount of glucose placebo. In addition, a pharmacokinetic study was carried out.

SETTING

The Rowett Research Institute, Aberdeen, UK.

SUBJECTS

Eighteen healthy non-obese normocholesterolaemic female volunteers in the age range 18-48 y.

MAIN OUTCOME MEASURES

Plasma flavonoids, ascorbic acid, tocopherols and carotenoids, plasma antioxidant capacity, lymphocyte DNA damage, blood chemistry and haematology, liver function tests, urinary malondialdehyde, 8-hydroxy-2-deoxyguanosine and 8-iso-prostaglandin F2alpha.

RESULTS

Eighteen volunteers completed the trial. Rutin supplementation did not induce any adverse changes in blood chemistry or indices of liver function. Plasma flavonoids were significantly elevated in the rutin-supplemented group. Endogenous oxidation of pyrimidines was significantly decreased in both rutin- and placebo-treated volunteers. There was no significant change in the level of urinary 8-hydroxy-2'-deoxyguanosine or urinary malondialdehyde in either group. A linear correlation was observed between urinary malondialdehyde and urinary 8-iso-prostaglandin F2alpha (R = 0.54, P<0.01).

CONCLUSION

Six weeks' rutin supplementation significantly elevated the levels of three plasma flavonoids (quercetin. kaempferol and isorhamnetin) but there was no significant change in plasma antioxidant status. The decrease in the level of endogenous base oxidation in lymphocyte DNA seen in both the placebo- and rutin-supplemented subjects may reflect seasonal changes in other dietary antioxidants.

Disposition of propofol between red blood cells, plasma, brain and cerebrospinal fluid in rabbits

The disposition of propofol in the blood and brain of New Zealand rabbits was studied in three groups of six rabbits. One group received a single anaesthetic dose; a second group received a 1-h infusion; and a third group was studied after the rabbits were judged to have recovered from a 1-h infusion. There was a high concentration of propofol in the red blood cell fraction and in the brain, however, the red blood cell concentration largely exceeded the one found in the brain in all groups of animals. This is consistent with the high fat solubility of diisopropylphenol. The possible effects of propofol sequestered in red blood cells is discussed.

Prolonged elimination half-life of phenol after dermal exposure

BACKGROUND

Phenol is a general protoplastic poison which has been in use in medicine and industry for decades. It is readily absorbed through the skin causing both local and systemic toxicity.

CASE REPORT

A 47-year-old male had 90% phenol spilled over his left foot and shoe (3% of body surface area). After a 4 1/2-hour exposure, manifestations included confusion, vertigo, faintness, hypotension, ventricular premature beats, atrial fibrillation, dark-green urine, and tense swelling, blue-black discoloration, hypalgesia, and hypoesthesia of the affected area. Treatment consisted of irrigation with copious amounts of water, incisions, and supportive measures.

RESULTS

Peak serum phenol was 21.6 micrograms/mL, considered in the fatal range. Peak urine phenol plus urine-conjugated phenol was 13,416 mg/g creatinine, indicating a major absorption. Elimination half-life was 13.86 hours, considerably longer than previously reported.

CONCLUSIONS

Prolonged skin contact with concentrated phenol in an occlusive environment may result in a major absorption and a long elimination half-life even if the area involved is small. Prolonged elimination may be explained by extensive tissue distribution or by "slow-release reservoir" properties of the skin. Such exposure may be associated with severe systemic and local toxicities. Immediate removal from exposure and aggressive decontamination of the skin are essential to reduce these risks.

Influence of gender and acetone pretreatment on benzene metabolism in mice exposed by nose-only inhalation

Benzene (BZ) requires oxidative metabolism catalyzed by cytochrome P-450 2E1 (CYP 2E1) to exert its hematotoxic and genotoxic effects. We previously reported that male mice have a two-fold higher maximum rate of BZ oxidation compared with female mice; this correlates with the greater sensitivity of males to the genotoxic effects of BZ as measured by micronuclei induction and sister chromatid exchanges. The aim of this study was to quantitate levels of BZ metabolites in urine and tissues, and to determine whether the higher maximum rate of BZ oxidation in male mice would be reflected in higher levels of hydroxylated BZ metabolites in tissues and water-soluble metabolites in urine. Male and female B6C3F, mice were exposed to 100 or 600 ppm 14C-BZ by nose-only inhalation for 6 h. An additional group of male mice was pretreated with 1% acetone in drinking water for 8 d prior to exposure to 600 ppm BZ; this group was used to evaluate the effect of induction of CYP 2E1 on urine and tissue levels of BZ and its hydroxylated metabolites. BZ, phenol (PHE), and hydroquinone (HQ) were quantified in blood, liver, and bone marrow during exposure and postexposure, and water-soluble metabolites were analyzed in urine in the 48 h after exposure. Male mice exhibited a higher flux of BZ metabolism through the HQ pathway compared with females after exposure to either 100 ppm BZ (32.0 2.03 vs. 19.8 2.7%) or 600 ppm BZ (14.7 1.42 vs. 7.94 + 0.76%). Acetone pretreatment to induce CYP 2E1 resulted in a significant increase in both the percent and mass of urinary HQ glucuronide and muconic acid in male mice exposed to 600 ppm BZ. This increase was paralleled by three- to fourfold higher steady-state concentrations of PHE and HQ in blood and bone marrow of acetone-pretreated mice compared with untreated mice. These results indicate that the higher maximum rate of BZ metabolism in male mice is paralleled by a greater proportion of the total flux of BZ through the pathway for HQ formation, suggesting that the metabolites formed along this pathway may be responsible for the genotoxicity observed following BZ exposure.

The effect of whisky and wine consumption on total phenol content and antioxidant capacity of plasma from healthy volunteers

OBJECTIVE

To assess whether consumption of 100 ml of whisky or red wine by healthy male subjects increased plasma total phenol content and antioxidant capacity.

DESIGN

A Latin square arrangement to eliminate ordering effects whereby, after an overnight fast, nine volunteers consumed 100 ml of red wine, malt whisky or unmatured 'new make' spirit. Each volunteer participated on three occasions one week apart, consuming one of the beverages each time. Blood samples were obtained from the anticubital vein at intervals up to 4h after consumption of the beverages when a urine sample was also obtained.

RESULTS

Within 30 min of consumption of the wine and whisky, there was a similar and significant increase in plasma total phenol content and antioxidant capacity as determined by the ferric reducing capacity of plasma (FRAP). No changes were observed following consumption of 'new make' spirit.

CONCLUSIONS

Consumption of phenolic-containing alcoholic beverages transiently raises total phenol concentration and enhances the antioxidant capacity of plasma. This is compatible with suggestions that moderate alcohol usage and increased antioxidant intake decrease the risk of coronary heart disease.

On-line supported liquid membrane-liquid chromatography with a phenol oxidase-based biosensor as a selective detection unit for the determination of phenols in blood plasma

The potential of on-line combination of supported liquid membrane extraction and column liquid chromatography with a phenol oxidase-based biosensor as a selective detection unit has been investigated for the determination of phenols in human plasma. The phenols are selectively extracted into a porous PTFE (polytetraflouroethene) membrane impregnated with a water-immiscible organic solvent and further into an alkaline acceptor phase. Via an ion-exchange interface, the analytes are transferred to a reversed-phase column where they are separated and detected using the biosensor. No sample pretreatment before the extraction, except centrifugation, is made. Due to the high selectivity both in the extraction and in the detection steps and to the fact that the demands on the chromatographic separation are low, a quick separation using an eluent with a low concentration of organic modifier can be made, without affecting the biosensor response. Detection limits below the 50 microg/l level in blood plasma were obtained for the three model compounds, phenol, p-cresol and 4-chlorophenol.