Effect Of Tyrosol Research Articles

Evaluation of the Bioaccessible Fraction of T-2 Toxin from Cereals and Its Effect on the Viability of Caco-2 Cells Exposed to Tyrosol.

The bioaccessibility of mycotoxins is an important factor that has to be considered when assessing the risk they pose to human health. Bioactive compounds like phenolics could play a protective role against the toxic effects of contaminants. In this work, the bioaccessible fraction of the T-2 toxin (T-2) contained in breakfast cereals and its effect on the viability of Caco-2 cells were investigated. Furthermore, the effect of tyrosol (a polyphenol abundant in EVOO) on T-2-induced cytotoxicity was evaluated in the same cell line. After standardized in vitro gastrointestinal digestion, the T-2 toxin was released from T-2-spiked breakfast cereals and further quantified by UHPLC-MS/MS. The bioaccessible fraction of T-2 was 51 ± 4%. The cell viability study was performed by pre-treating the cells for 24 h with tyrosol (25, 50 and 100 µM) and subsequently adding T-2 at 15 nM or by treating the cells with a combination of tyrosol and T-2. In the simultaneous treatment, 25 µM tyrosol prevented the toxic effects produced by the exposure to T-2 at 15 nM; however, cytotoxic effects were observed for the other combinations tested. The pre-treatment of Caco-2 cells with tyrosol did not attenuate the cytotoxic effects caused by exposure to T-2. These results suggest that tyrosol at low concentrations (25 µM) could exert a cytoprotective effect on Caco-2 cells against 15 nM T-2 when administered simultaneously with T-2. However, more studies are required to corroborate this hypothesis.

Antihyperlipidemic effect of tyrosol, a phenolic compound in streptozotocin-induced diabetic rats

We investigated the antihyperlipidemic effects of tyrosol in streptozotocin (STZ)-induced diabetic rats. Rats were injected intraperitoneally with STZ (40 mg/kg), and these established experimental rats were treated with tyrosol (20 mg/kg) and glibenclamide (600µg/kg) for 45 days. The observed results revealed that tyrosol treatment significantly reduced plasma glucose, plasma, and liver total cholesterol, triglycerides, free fatty acids, phospholipids, plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, atherogenic index, and significantly increased plasma insulin and high-density lipoprotein cholesterol in STZ-induced diabetic rats. The activity of 3-hydroxy 3-methylglutaryl coenzyme A reductase significantly reduced in the liver, whereas the activities of lipoprotein lipase and lecithin cholesterol acyltransferase were significantly increased in the plasma of tyrosol treated STZ-induced diabetic rats. Histological examination showed that tyrosol treatment remarkably reduced lipid accumulation in the liver of STZ-induced diabetic rats. The present study revealed that tyrosol exhibits potent antihyperlipidemic effects in STZ-induced diabetic rats.

Evaluation of tyrosol and farnesol as inducer in pigment production by Monascus purpureus ATCC16365.

This study focused on investigating the effect of exogenously applied two quorum sensing molecules (tyrosol and farnesol) on the synthesis of bioactive metabolites (pigments, lactic acid, ethanol, and citric acid) in Monascus purpureus ATCC16365. None of the tested concentrations (62.5, 125, 250, and 500 µl/L) of farnesol affected the synthesis of metabolites as well as cell growth. As with farnesol application, none of the tested concentrations (3.45, 6.9, 13.8, and 27.6 mg/L) of tyrosol caused a significant change in the synthesis of lactic acid and citric acid as well as cell growth. Conversely, all of the tested concentrations of tyrosol increased pigment synthesis but reduced ethanol synthesis, compared with the control. Maximum increases (3.16-, 2.68-, and 2.87-fold increase, respectively) in yellow, orange, and red pigment production were achieved, especially when 6.9-mg/L tyrosol was added to the culture on day 3. On the contrary, 6.9-mg/L tyrosol reduced the content of citrinin by approximately 51.5%. This is the first report on the effect of tyrosol and farnesol on the synthesis of Monascus metabolites. Due to potential properties, such as low price, nonhuman toxicity, promotion of pigment synthesis, and reduction in citrinin synthesis, tyrosol can be used as a novel inducer in the fermentative production of Monascus pigments.

Effect of tyrosol on myocardial ischemia-reperfusion injury in diabetic rats and the role of SIRT1/AMPK/eNOS signaling pathway

Objective To evaluate the effect of tyrosol on myocardial ischemia-reperfusion (I/R) injury in diabetic rats and the role of silent mating-type information regulation 1 (SIRT1)/adenosine monophosphate-activated protein kinase (AMPK)/endothelial nitric oxide synthase (eNOS) signaling pathway. Methods SPF healthy adult male Sprague-Dawley rats, weighing 200-220 g, were intraperitoneally injected with streptozotocin 60 mg/kg to establish the model of diabetes mellitus.Fifty-six diabetic rats were divided into 4 groups (n=14 each) using a random number table method: sham operation group (S group), myocardial I/R group(I/R group), myocardial I/R plus tyrosol group (I/R+ T group), and myocardial I/R plus tyrosol plus SIRT1 inhibitor EX527 group (I/R+ T+ E group). In I/R+ T and I/R+ T+ E groups, tyrosol 20 mg·kg-1·d-1 was given by gavage for 45 consecutive days, and the equal volume of normal saline was given in the other two groups.In I/R+ T+ E group, EX527 5 mg·kg-1·d-1 was intraperitoneally injected for 3 consecutive days before ischemia, and EX527 5 mg/kg was intraperitoneally injected at 20 min before reperfusion.Myocardial I/R was induced by ligation of the left anterior descending branch of coronary artery for 30 min followed by 2-h reperfusion.The myocardial infarct volume was measured by TTC staining.The levels of creatine kinase-MB (CK-MB), lactic dehydrogenase (LDH) and 5-F2t-isoprostane in serum and superoxide dismutase (SOD) in myocardial tissues were detected by enzyme-linked immunosorbent assay.The expression of SIRT1, AMPK, phosphorylated AMPK (p-AMPK), eNOS and p-eNOS was detected by Western blot. Results Compared with S group, the levels of serum CK-MB, LDH and 15-F2t-Isoprostane and myocardial infarction volume were significantly increased, the SOD activity was decreased, and the SIRT1 expression was down-regulated in I/R group, and the levels of serum CK-MB, LDH and 15-F2t-Isoprostane and myocardial infarction volume were significantly increased, the SOD activity was decreased, the SIRT1 expression was down-regulated, and the expression of p-AMPK and p-eNOS was up-regulated in I/R+ T and I/R+ T+ E groups (P 0.05). Compared with I/R+ T group, the levels of CK-MB, LDH and 15-F2t-isoprostane in serum and myocardial infarct volume were significantly increased, the SOD activity was increased, and the expression of SIRT1, p-AMPK and p-eNOS was down-regulated in I/R+ T+ E group (P<0.05). Conclusion Tyrosol can mitigate myocardial I/R injury, and the mechanism may be related to activating SIRT1/AMPK/eNOS signaling pathway and inhibiting oxidative stress response in diabetic rats. Key words: Antioxidants; Diabetes mellitus; Myocardial reperfusion injury; Sirtuin 1; Protein-serine-threonine kinases; Nitric oxide synthase

English

Staphylococcus aureus is considered the most common causative agent of community and hospital-acquired infections. The isolates with increased virulence and antimicrobial resistance, especially mecithillin resistant S. aureus (MRSA), represent a challenge in hospitals and health care facilities worldwide. The effect of tyrosol, a phenolic quorum sensing compound of Candida albicans, was studied on the sensitivity of clinical MRSA isolates to antibiotics. Besides having antibacterial activity, subinhibitory concentrations (3.5 - 14.3 mM) of tyrosol increased the susceptibility to antimicrobial. It gave either synergistic or additive effect when combined with gentamicin, amikacin and ciprofloxacin. Also, the effect of such concentrations on virulence factors production was investigated. Biofilm formed was significantly decreased in most of the tested isolates (P≤0.0001). In addition, it significantly decreased the production of protease and lipase enzymes. Overall, these results represent a promising method for inhibiting S. aureus either by reducing its resistance to antibiotics or decreasing the production of virulence factors. Key words: Staphylococcus aureus, tyrosol, antibiotic sensitivity, virulence factors.

Effect of tyrosol and trichoderma parareesei chorismate mutase silenced mutants in light perception by arabidopsis plants

Effect of tyrosol and trichoderma parareesei chorismate mutase silenced mutants in light perception by arabidopsis plants

Effect of tyrosol on adhesion of Candida albicans and Candida glabrata to acrylic surfaces.

The prevention of adhesion of Candida cells to acrylic surfaces can be regarded as an alternative to prevent denture stomatitis. The use of quorum sensing molecules, such as tyrosol, could potentially interfere with the adhesion process. Therefore, the aim of this study was to assess the effect of tyrosol on adhesion of single and mixed cultures of Candida albicans and Candida glabrata to acrylic resin surfaces. Tyrosol was diluted in each yeast inoculum (10(7) cells/ml in artificial saliva) at 25, 50, 100, and 200 mM. Then, each dilution was added to wells of 24-well plates containing the acrylic specimens, and the plates were incubated at 37°C for 2 h. After, the effect of tyrosol was determined by total biomass quantification, metabolic activity of the cells and colony-forming unit counting. Chlorhexidine gluconate (CHG) was used as a positive control. Data were analyzed using analysis of variance (ANOVA) and the Holm-Sidak post hoc test (α = 0.05). The results of total biomass quantification and metabolic activity revealed that the tyrosol promoted significant reductions (ranging from 22.32 to 86.16%) on single C. albicans and mixed cultures. Moreover, tyrosol at 200 mM and CHG significantly reduced (p < 0.05) the number of adhered cells to the acrylic surface for single and mixed cultures of both species, with reductions ranging from 1.74 to 3.64-log10. In conclusion, tyrosol has an inhibitory effect on Candida adhesion to acrylic resin, and further investigations are warranted to clarify its potential against Candida infections.

The effect of tyrosol, hydroxytyrosol and oleuropein on the non-enzymatic lipid peroxidation of rat liver microsomes.

The effects of the polyphenolic compounds from virgin olive oil: tyrosol, hydroxytyrosol and oleuropein on the non-enzymatic lipid peroxidation induced by ascorbate-Fe2+ of rat liver microsomes were examined. The inhibition of light emission (maximal induced chemiluminescence) by oleuropein was concentration dependent. Hydroxytyrosol showed a substantial degree of inhibition against ascorbate-Fe2+ induced lipid peroxidation in rat liver microsomes that was at least 6 times higher than that observed in the presence of oleuropein. Inhibition of lipid peroxidation by tyrosol was not observed. In rat liver microsomes incubated alone or in the presence of tyrosol, the fatty acid composition was profoundly modified when subjected to in vitro peroxidation mediated by ascorbate-Fe2+, with a considerable decrease of 18:2n6 and 20:4n6; however, changes in fatty acid composition were not observed when microsomes were incubated with hydroxytyrosol. When oleuropein was used at low concentration (5, 15 microM) a considerable decrease of 20:4n6 was observed, but 18:2n6 was not modified; at higher concentration (30, 60 microM) changes in fatty acid composition were not observed. There was a very good correlation between the presence of oxidized phospholipids and the changes in polyunsaturated fatty acids previously observed. Thus, hydroxytyrosol showed the highest protection again oxidized phospholipid formation. The presence of oleuropein at low concentration (5, 15 microM) does not prevent the formation of oxidized phospholipids (8.02 +/- 1.22 and 1.22 +/- 1.22) but concentration higher than 30 microM avoids completely the formation of this molecules whereas tyrosol at any concentration assayed was found to be ineffective and allows the formation not only of oxidized phospholipids but also of oxidized cholesterol.