Antonios E. Koutelidakis

Green tea, white tea, and Pelargonium purpureum increase the antioxidant capacity of plasma and some organs in mice

OBJECTIVE We tested in mice the hypothesis that ingestion of infusions of green tea, white tea, or the aromatic plant Pelargonium purpureum increases total antioxidant capacity (TAC) of plasma and organs. METHODS Twenty-five mice were randomly assigned to five groups, each of which received by gavage 0.1 mL of infusion from green tea, white tea, or P. purpureum (8 g/100 mL of water) or catechin (0.01 g/100 mL) or water for 5 consecutive days. On the fifth day the animals were euthanized. Blood was taken by heart puncture and the heart, lungs, liver, spleen, kidney, and brain were removed. TAC was measured in plasma and in all organ homogenates with the ferric reducing antioxidant power assay and in selected organ homogenates by the total radical-trapping antioxidant parameter assay. RESULTS Green tea and P. purpureum increased TAC in the plasma and lungs, whereas green tea, white tea, and catechin increased TAC in heart homogenates. No effect was observed on the liver, brain, spleen, and kidney homogenates in comparison with the water control with the ferric reducing antioxidant power assay or the total radical-trapping antioxidant parameter assay. CONCLUSION These results suggest that green tea, white tea, and P. purpureum exhibit antioxidant effects in vivo that may be observed not only in plasma but also in some organs.

Phytosterols supplementation decreases plasma small and dense LDL levels in metabolic syndrome patients on a westernized type diet.

BACKGROUND AND AIMS Several studies have observed a hypocholesterolemic effect of plant sterols in hypercholesterolemic patients on a balanced diet. The aim of this study was to examine the effect of phytosterol supplementation on risk factors of coronary artery disease in metabolic syndrome patients on a Westernized type diet. METHODS AND RESULTS In a randomized placebo-controlled design 108 patients with metabolic syndrome were assigned to consume either 2 plant sterol-enriched yogurt mini drink which provided 4 g phytosterols per day, or a yogurt beverage without phytosterols (control). The duration of the study was 2 months and the patients in both groups followed their habitual westernized type diet and recording it on food diaries. Blood samples were drawn at baseline and after 2 months of intervention. After 2 months supplementation with phytosterols, a significant reduction in total cholesterol, LDL-cholesterol, small and dense LDL (sdLDL) levels, as well as, apoB and triglycerides concentrations were observed in the intervention group (P < 0.05) compared to the control group. In addition, phytosterol supplementation lowered serum total cholesterol by 15.9%, LDL-cholesterol by 20.3% and triglyceride levels by 19.1% (P = 0.02, P < 0.001 and P < 0.001, respectively), although the patients kept their habitual westernized type diet. No differences were observed in HDL cholesterol, apoA1, glucose, C-reactive protein, fibrinogen levels and blood pressure. CONCLUSIONS Phytosterol supplementation improves risk factors of coronary artery disease even if the diet is a westernized type.

Phytosterol supplementation does not affect plasma antioxidant capacity in patients with metabolic syndrome.

Several studies have observed decreased levels of lipophilic antioxidants after supplementation with phytosterols and stanols. The aim of this study was to examine the effect of phytosterol supplementation on plasma total antioxidant capacity in patients with metabolic syndrome. In a parallel arm, randomized placebo-controlled design, 108 patients with metabolic syndrome were assigned to consume yogurt beverage which provided 4 g of phytosterols per day or yogurt beverage without phytosterols. The duration of the study was 2 months and the patients in both groups followed their habitual westernized type diet. Blood samples were drawn at baseline and after 2 months, and the total antioxidant capacity of plasma was measured using the ferric reducing antioxidant power of plasma and oxygen radical absorbance capacity assays. After 2 months of intervention, plasma total antioxidant capacity did not differ between and within the intervention and the control groups. Phytosterol supplementation does not affect plasma antioxidant status.

The Effect of Iron and Fat in a Diet Containing Green Tea Extract (Camellia sinensis) on the Antioxidant Capacity of Some Organs and the mRNA Expression of Specific Genes in Mice

The hypothesis that iron and fat in the diet may affect green tea extract (GTE) bioactivity, in particular antioxidant capacity and gene expression, was proposed and tested in mice. Thirty mice were randomly assigned to have for 37 days free access to standard or high-fat diets with or without GTE and ferrous lactate. Mice were euthanized and specific organs were removed. Total antioxidant capacity (TAC) was measured using the ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity assays. Polymerase chain reaction was performed on liver and heart mRNA extracts. The FRAP assay showed that GTE from the standard diet did not affect plasma TAC but increased TAC of heart, aorta, and duodenum. GTE from diets enriched with iron resulted to lower TAC of liver and heart than diets with GTE alone. GTE from the fatty diet did not have any effect on TAC compared with fatty control diet, but increased TAC in heart and aorta compared with standard control diet. An effect on expression of the mapk-1 and NF-kB genes in heart was observed in the presence of GTE. These results suggest that GTE may exhibit bioactivity in some organs affected by dietary fat and iron. The findings of this study contribute to the elucidation of the role of dietary components on tea bioactivity.

Total antioxidant capacity, total phenolic content and iron and zinc dialyzability in selected Greek varieties of table olives, tomatoes and legumes from conventional and organic farming

Abstract The objective was to compare 10 types of table olives, 11 types of tomatoes and tomato products and 18 types of legumes from conventional or organic farming for selected nutritional properties. All products were tested for their total antioxidant capacity (TAC) (Ferric Reducing Antioxidant Power (FRAP) assay) and total phenolic content (Folin-Ciocalteau method). Tomatoes and legumes were further tested for iron and zinc dialyzability after in vitro digestion. Ascorbic acid content of tomatoes was also measured. The study resulted that the nutritional properties of olives, tomatoes and legumes tested were different among the various cultivars but, in most cases, not between products from organic or conventional farming. Natural black olives, cherry and santorini tomatoes and lentils exhibited superior nutritional properties.

Ingesting iron together with white tea (Camellia Sinensis) may decrease its antioxidant capacity and phenolic content in human plasma

It was hypothesized that ironpolyphenol chelates formed in the lumen or in the food matrix are poorly absorbed, thus tea bioactivity may be affected when iron is ingested together with tea. Ten women, aged 25 – 55 years, received white tea infusion or a mixture of white tea infusion and iron lactate in a randomized cross over design. Blood samples were drawn before the administration of and 30, 60 and 90 min after the consumption of the test drinks. White tea increased the antioxidant capacity measured with Ferric Reducing Antioxidant Power assay (FRAP) and the phenolic content of plasma measured with total catechin and High Performance Liquid Chromatography (HPLC) assays (p < 0.0001) in a time dependent way (p < 0.0001) but in the presence of iron the increase was lower (p = 0.0057). These results suggest that iron may modify the antioxidant properties of tea polyphenols and are in support of the hypothesis.

In Vitro Antioxidant Properties of Mediterranean Herbs and their Bioactivity

Herbs contain phenolics, which are among the most desirable bioactive substances in food because of their antioxidant capacity and antimicrobial activity. In addition, the health-protecting capacity of plant phenolics is of great importance to both consumers and producers. The phenolic substances of some Mediterranean herb extracts (mint, mountain tea, dictamnus, oregano and pelargonio) were identified and quantified by RP-HPLC-UV-vis, after comparison with reference standards. The inhibition of lipid oxidation of the extracts was determined by the Rancimat test using sunflower oil as substrate. Free radical scavenging activity was measured using the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). The ferric reducing antioxidant power (FRAP) assay was also employed to measure the reducing power of herb antioxidants. The total phenol concentration of the extracts was estimated with thr Folin–Ciocalteu reagent using gallic acid as standard. The bioactivity of one of these herbs was investigated with an in vivo animal model. An infusion of pelargonio increased the total antioxidant capacity of mice plasma, colon, and lungs and reduced colon, susceptibility after oxidation induced from iron fortificants after in vitro digestion.