Francesca Ieri

Antimicrobial and antiviral activity of hydrolysable tannins.

Hydrolysable tannins (HTs), secondary metabolites widely distributed in the plant kingdom, are generally multiple esters of gallic acid with glucose. HTs have been shown to be effective antagonists against viruses, bacteria and eukaryotic microorganisms. The present review examines the antimicrobial and antiviral activity of HTs, the mechanism(s) of action, and some structure-activity relationships.

Effect of cooking on the anthocyanins, phenolic acids, glycoalkaloids, and resistant starch content in two pigmented cultivars of Solanum tuberosum L.

HPLC/DAD/MS analysis of the phenolic acids and anthocyanin content of three cultivars of Solanum tuberosum L. (Vitelotte Noire, Highland Burgundy Red, with pigmented flesh, and Kennebec with white pulp) was performed. The analyses were carried out both on fresh tubers and after cooking treatments (boiling and microwaves). Starch digestibility and the % of resistant starch were also determined on cooked tubers by in vitro methods. For the pigmented potatoes, the heating treatment did not cause any changes in the phenolic acids content, while anthocyanins showed only a small decrement (16-29%). The cv. Highland Burgundy Red showed anthocyanins and phenolic acid concentrations close to 1 g/kg and more than 1.1 g/kg, respectively. Vitellotte Noire showed the highest amounts of resistant starch. Potato starch digestibility and % of resistant starch, considered as a component of dietary fiber, were affected both by cultivar and by heating/cooling treatments.

Study of the phenolic composition of spanish and italian monocultivar extra virgin olive oils: Distribution of lignans, secoiridoidic, simple phenols and flavonoids

The aim of the present study was to compare the phenolic content in selected monocultivar extra virgin olive oils. Analyses were carried out by HPLC/DAD/MS on Picual, Picuda, Arbequina and Hojiblanca oils from Spain and Seggianese and Taggiasca oils from Italy. Oils from cultivar Picual showed similar characteristics to those of Seggianese oils, with total amounts of secoiridoids of 498.7 and 619.2mg/L, respectively. The phenolic composition of Arbequina oils is close to that of the Taggiasca variety with lignans among the main compounds. The determination of free and linked OH-Tyr, by way of an acid hydrolysis, represents a rapid and suitable method, especially when standards are not available, to determine antioxidant potentialities in terms of MPC, particularly for fresh extra virgin olive oils rich in secoiridoidic derivatives.

Antioxidant Effect of Two Virgin Olive Oils Depends on the Concentration and Composition of Minor Polar Compounds

In vitro studies show that some individual minor polar phenolic compounds (MPC) present in virgin olive oil prevent oxidation of human low-density lipoproteins (LDL), but few data are available on the antioxidant effect of whole oil extract. Thus, whole virgin olive extracts were studied to determine whether they maintain the antioxidant activity and whether this last is linked to MPC composition of a single virgin oil. Using HPLC-DAD the MPC content in Taggiasca and Seggianese virgin olive oils was measured. Taggiasca oil was less rich in total MPC (208.5 mg/L) than Seggianese oil (441.9 mg/L). In addition, the major compounds of Taggiasca oil were lignan derivatives, whereas the major compounds in Seggianese oils were secoiridoid derivatives. Moreover, Taggiasca oil was practically free of 5-hydroxytyrosol and 5-hydroxytyrosol derivatives, deacetoxy-oleuropein aglycone and oleuropein aglycone. The antioxidant activity of the oils on human LDL was evaluated by measuring malondialdehyde and conjugate diene generation induced by copper ions. In both tests, the oil extracts dose-dependently reduced malondialdehyde and conjugate diene generation. Moreover, antioxidant potency correlated with total MPC; thus, Seggianese extract was more active. The two oils differed quantitatively and qualitatively, and these differences influenced their biological activities; thus clinical trials focused on studying the effects of olive oils should specify the oils used.

Minor polar compounds in extra virgin olive oil: correlation between HPLC-DAD-MS and the Folin-Ciocalteu spectrophotometric method.

Minor polar compounds of 88 extra virgin olive oils were analyzed by HPLC-DAD-MS (high-performance liquid chromatography-diode array detector-mass spectrometry) and by the Folin-Ciocalteu (FC) spectrophotometric method, to validate and evaluate, for olive oils, the linear association between FC and HPLC data. The Pearson correlation coefficients were calculated between HPLC and FC results. The highest, positive R were related with deacetoxyoleuropein aglycone (R = 0.93) and oleuropein aglycone (R = 0.93) as single compounds and with the sum of orthodiphenols (R = 0.94) and the sum of all compounds (R = 0.95), showing that both estimations of total phenols content are reliably correlated, regardless for the absolute contents and are independent of the relative composition of the phenolic fraction. On the other hand the HPLC quantifications of apigenin and lignans showed no significant correlation with FC. These results, supported also by principal component analysis, may suggest caution about the interpretation of FC results to compare olive oils with very different phenolic profiles.

In Vitro Effects of Extracts of Extra Virgin Olive Oil on Human Colon Cancer Cells

The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular diseases, and some types of cancer. Recent interest has been focused on the biological activity of phenolic compounds present in extra virgin olive oils (EVOOs). Both in vivo and in vitro studies have shown that EVOO components have positive effects on metabolic parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet function, and antimicrobial activity. We have investigated the possible interactions between 2 extracts of extra virgin olive oil and estrogen receptor β (ERβ) in an in vitro model of colon cancer. The qualification and quantification of the components of the 2 samples tested showed that phenolic compounds—hydroxytyrosol, secoiridoids, and lignans—are the major represented compounds. EVOO extracts were tested on a colon cancer cell line engineered to overexpress ERβ (HCT8-β8). By using custom made Oligo microarray, gene expression profiles of colon cancer cells challenged with EVOO-T extracts when compared with those of cells exposed to 17β-estradiol (17β-E2). This study demonstrated that the EVOO extracts tested showed an antiproliferative effect on colon cancer cells through the interaction with estrogen-dependent signals involved in tumor cell growth. Specifically, the ability of EVOO extracts to inhibit cell proliferation was superimposable to the activation of the ERβ receptor, similar to what was observed after 17β-E2 challenge.

Plant polyphenol content, soil fertilization and agricultural management: a review

Abstract The review deals with polyphenol content of vegetables and fruits under different experimental conditions. The effect of fertilizers, mainly nitrogen containing fertilizers, on qualitative and especially quantitative content of the polyphenols mixture, was reviewed. Soil nitrogen affects both anthocyanins and flavonoids content, and generally, a higher polyphenolic content is observed when less nitrogen fertilizer is added to the soil. Also the effect of different agricultural management (conventional, organic, biodynamic, integrate) is reviewed with respect to polyphenols. In this case, a major effect has pointed out in the case of vegetables, while agricultural practice affects in a minimal way fruits polyphenols content. The effect of different management is, however, hardly pointed out, since many environmental factors are involved and affect polyphenols biosynthetic pathway.

Allergic contact dermatitis caused by a blood pressure cuff

To the Editor: N-isopropyl-N-phenyl-p-phenylenediamine (IPPD) is used primarily in the manufacture of black rubber products, and its cross-reactivity with p-phenylenediamine (PPD), a common hair dye, is possible. A 78-year-old nonatopic woman with a history of hypertension and coronary artery disease underwent a dipyridamole stress echocardiography. During this procedure, her blood pressure was monitored for 45 minutes. One day later, a pruritic, sharply demarcated, erythematous vesicular eruption developed at the site of contact with the blood pressure cuff. Slight improvement was obtained with topical corticosteroids (Fig 1) and the dermatitis completely cleared after 7 days of treatment with oral corticosteroids. A clinical diagnosis of contact dermatitis due to the blood pressure cuff was made. One month later, the woman was patch tested with the standard Italian Society of Allergological, Occupational and Environmental Dermatology (SIDAPA) series. At day 2 and day 4, a positive reaction (11) to IPPD (0.1% in petrolatum) was recorded. PPD (1% in petrolatum), included in the standard series, did not show a positive reaction. Strong response (111) was elicited when a fragment of the blood pressure cuff was patch tested as is. A skin prick test to latex protein was negative. In addition, the patient gave a positive history of hand eczema to rubber gloves. The inner part of the sphygmomanometer was composed of black rubber and lined by a nylon cuff. According to the manufacturer, there is no information available concerning the composition of the rubber. Chemical analysis was conducted to verify the presence of IPPD in the nylon cuff. In previous studies, the determination of IPPDwas carried out by gas chromatographyemass spectrometry and highperformance liquid chromatography (HPLC). In this study, after incubation with dichloromethane (CH2Cl2) for 24 hours, a piece of tissue extracted from the nylon section of the sphygmomanometer was submitted to HPLC interfaced with an API3000 mass spectrometer that was triple quadrupole equipped with a turbo ion spray. Spectroscopy was comparatively performed on the standard IPPD allergen. The quasimolecular ion m/z 227 [M 1 H] and the fragment m/z 184 confirmed the presence of IPPD in the tissue,which had a sample content of 38.5 ppm.

Minor Polar Compounds in Olive Oil and NF-κB Translocation

Publisher Summary The cardio-protective role of olive oil has been highlighted in several studies and beneficial health effects have been attributed, at least in part, to the presence of non-nutrient minor polar compounds (MPC). As an example, phenolic compounds in virgin olive oil improve endothelial function in hypercholesterolemic patients and inhibit low-density lipoprotein (LDL) oxidation in humans and animals, in vivo and in vitro, hydroxytyrosol and oleuropein being also potent scavengers of several free radicals. After consumption of 25 mL extra virgin olive oil, plasma concentrations of hydroxytyrosol range from 50 to 160 nM. Hydroxytyrosol affects oxidative stress as well as arachidonic acid mobilization and metabolism by macrophage RAW 264.7 cells. In the same cell line, it also reduces iNOS (inducible nitric oxide synthase) and COX-2 (cyclo-oxygenase 2) gene expression, mainly by preventing the activation of NF-κB (nuclear factor-kappa B), STAT-1α (signal transducer and activator of transcription-1α), and IRF-1 (interferon regulatory factor-1). At nutritionally relevant concentrations, hydroxytyrosol reduces monocyte adhesion to human endothelial cells, as well as the expression of adhesion molecules such as VCAM-1 (vascular cell adhesion molecule-1), an effect that seems to be mediated by NF-κB and activator protein-1 (AP-1). The redox-sensitive transcription factor NF-κB can be activated by various stimuli, including reactive oxygen species, oxidized LDL, hypoxia/anoxia, cytokines, and bacterial and viral products, and is largely recognized as a therapeutic target in inflammation and atherosclerosis.