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The in vivo antioxidant, anti-inflammatory, and anti-hyperglycemic activities of Salvia splendens extracts (100 mg kg−1d−1 P.O.) in male albino rats were studied. The total 70% methanolic, total aqueous and successive ethyl acetate extracts demonstrated antioxidant and anti-inflammatory activities. The results suggested that S. splendens may have supportive role in controlling diabetic conditions due to the presence of poly-phenolic compounds. [ABSTRACT FROM AUTHOR]

In this investigation, 14 extra virgin olive oils (EVOOs), produced with Leccino and Raggiola olive cultivars, by a new two-way (2W) decanter were compared with 14 EVOOs produced by means of a conventional three-way (3W) decanter. The 2W EVOOs had higher phenol concentrations, as shown by high-performance liquid chromatography/diode array detection (HPLC-DAD) analysis and yielded a higher extraction of the 3,4-DHPEA-EDA (oleacein), 3,4-DHPEA-EA (oleuropein aglycone) andp-HPEA-EDA (oleocanthal). The concentrations of lignans, (+)-pinoresinol and (+)-1-acetoxypinoresinol, detected by HPLC-FLD equipment, were higher in the 2W EVOOs than they were in EVOOs produced using the 3W system. Total phenols, detected by the Folin–Ciocalteu assay, were lower than those obtained by HPLC, but they significantly correlated (p < 0.05). The antioxidant capacity (ORAC) values of 2W EVOOs were higher than those of 3W EVOOs. In conclusion, the 2W system provided high-quality phenol EVOOs and became an indispensable tool when adverse climatic conditions reduced the olive secoiridoid concentration. [ABSTRACT FROM PUBLISHER]

Olive oil, an oil rich in monounsaturated fatty acids (MUFCs) and minor constituents including phenolic compounds, is a major component of the Mediterranean diet. The potential health benefits of the Mediterranean diet were highlighted by the seminal Seven Countries Study, and more contemporary research has identified olive oil as a major element responsible for these effects. It is emerging that the phenolic compounds are the most likely candidates accounting for the cardioprotective and cancer preventative effects of extra virgin olive oil (EVOO). In particular, the phenolic compound, hydroxytyrosol has been identified as one of the most potent antioxidants found in olive oil. This review will briefly consider historical aspects of olive oil research and the biological properties of phenolic compounds in olive oil will be discussed. The focus of the discussion will be related to the mechanisms of action of hydroxytyrosol. Studies have demonstrated that hydroxytyrosol induces apoptosis and cell cycle arrest in cancer cells. Further, research has shown that hydroxytyrosol can prevent cardiovascular disease by reducing the expression of adhesion molecules on endothelial cells and preventing the oxidation of low-density lipoprotein (LDL). The molecular mechanisms accounting for these effects are reviewed. [ABSTRACT FROM AUTHOR]

Oxidative stress has been related increasingly to the onset and/or progression of a growing number of human diseases. However, large studies on supplementation with anti-oxidants for prevention or treatment of different pathologies have yielded contradictory and mostly negative results, as documented by numerous meta-analyses and clinical trials. Here we analyze in detail the findings of these studies and discuss major aspects that, in our opinion, are likely to be responsible for these confounding data. With the belief that a clear correlation between disease and oxidative stress is far from being proven for most pathological conditions, our argument focuses on the following points: i) choice of biomarker(s) and/or the biological system(s) for the analyses; ii) pitfalls in pre-analytical and analytical methods for assessing oxidative stress; and iii) scientific misconduct. Eventually, suggestions aiming to obtain more convergent results on this topic are provided. [ABSTRACT FROM AUTHOR]

Glutathione is an intracellular antioxidant that often becomes depleted in pathologies with high oxidative loads. We investigated the provision of cysteine for glutathione synthesis to the human erythrocyte (red blood cell; RBC). Almost all plasma cysteine exists as cystine, its oxidized form. In vitro, extracellular cystine at 1.0 mM sustained glutathione synthesis in glutathione-depleted RBCs, at a rate of 0.206 ± 0.036 μmol (L RBC)-1min-1 only 20% of the maximum rate obtained with cysteine or N-acetylcysteine. In plasma-free solutions, N-acetylcysteine provides cysteine by intracellular deacetylation but to achieve maximum rates of glutathione synthesis by this process in vivo, plasma N-acetylcysteine concentrations would have to exceed 1.0 mM, which is therapeutically unattainable. 1H-NMR experiments demonstrated that redox exchange reactions between NAC and cystine produce NAC-cysteine, NAC-NAC and cysteine. Calculations using a mathematical model based on these results showed that plasma concentrations of N-acetylcysteine as low as 100 μM, that are attainable therapeutically, could potentially react with plasma cystine to produce ∼50 μM cysteine, that is sufficient to produce maximal rates of glutathione synthesis. We conclude that the mechanism of action of therapeutically administered N-acetylcysteine is to reduce plasma cystine to cysteine that then enters the RBC and sustains glutathione synthesis. [ABSTRACT FROM AUTHOR]

The effect of sulfur dioxide (SO2) on hippocampus antioxidant status, lipid peroxidation and learning and memory was investigated in diabetic rats. A total of 40 rats were divided into four equal groups: Control (C), SO2 + C (SO2), diabetic (DM) and SO2 + D (DMSO2). Experimental diabetes mellitus (DM) was induced by i.v injection of alloxan with a dose of 50 mg/kg body weight. Ten ppm SO2 was administered to the rats in the sulfur dioxide groups in an exposure chamber. Exposure occurred 1 h/d, 7 d/wk, for 6 wk; control rats were exposed to filtered air during the same time periods. SO2 exposure, while markedly increasing Cu-Zn Superoxide dismutase activity, significantly decreased glutathione peroxidase activity in diabetic and non-diabetic groups compared with the C group; hippocampus catalase activity was unaltered. Hippocampus thiobarbituric acid reactive substances (TBARS) were found to be elevated in all experimental groups with respect to control group. The active avoidance training results indicated that diabetic condition has been associated with learning and memory impairment. SO2 exposure caused deficits of learning and memory. Diabetes mellitus-induced impairment of learning and memory were potentiated by SO2 exposure. These findings suggest that exposure to SO2 by increasing lipid peroxidation, can change antioxidant enzyme activities and can elevated intensity of deficits of learning and memory in diabetic rats. [ABSTRACT FROM AUTHOR]

We are applying a dynamic systems biology approach to the development of several phenolic phytochemicals in food-grade plants as ingredients for functional food applications. Phenolic antioxidant phytochemicals from food-grade plants will be an important part of a healthy diet in a global population that is projected to reach 9 billion in the next 50 years. Such phytochemicals are being targeted for designing conventional foods with added health benefits (functional foods). Such value-added foods are needed for dietary support to manage major oxidation-linked diseases, such as diabetes, cardiovascular disease, arthritis, cognition diseases and cancer. Plants produce phenolic metabolites as a part of growth, developmental and stress-adaptation response. These stress and developmental-modulated phenolic phytochemicals can be targeted for the design of functional foods. In order to design consistent food-grade phytochemical profiles for safety and clinical relevancy, novel tissue culture and bioprocessing technologies have been developed. The strategy for designing these phenolic phytochemicals is based on the model that phenolic metabolites in plants are efficiently produced through an alternative mode of metabolism that links proline synthesis to activity of the pentose-phosphate pathway. Using the proline-linked pentose-phosphate pathway model, techniques have been developed to isolate high phenolic clonal lines of food-grade plants from single heterozygous seeds. Further, using the same model, elicitation concepts and techniques have been applied to over-produce phenolic metabolites in seeds and sprouts. In both clonal and seed sprout systems, exogenous treatment of phenolic phytochemicals from a non-target species elicited endogenous stimulation of phenolic synthesis and, potentially, an antioxidant response. From these investigations, a hypothetical model has been proposed in which the proline-linked pentose-phosphate pathway is critical for modulating... [ABSTRACT FROM AUTHOR]

The diabetic state confers an increased propensity to accelerated atherogenesis. In addition to the established risk factors, there is evidence for increased oxidative stress and inflammation in diabetes. Increased oxidative stress is manifested by increased lipid peroxidation (e.g. increased F 2 -isoprostanes) and increased DNA damage. Evidence for increased inflammation includes increased monocyte superoxide and pro-inflammatory cytokine release (IL-1, IL-6, and TNF-α), increased monocyte adhesion to endothelium and increased levels of plasma C-reactive protein, the prototypic marker of inflammation. Most importantly, alpha tocopherol therapy, especially at high doses, clearly shows a benefit with regards to LDL oxidation, isoprostanes and a decrease in inflammatory markers such as C-reactive protein, pro-inflammatory cytokines and PAI-1 levels. Thus, it appears that, in diabetes, alpha tocopherol therapy could emerge as an additional therapeutic modality. [ABSTRACT FROM AUTHOR]

To evaluate oxidative stress in type I diabetes mellitus, two antioxidant enzymes in erythrocytes, copper-zinc superoxide dismutase (SOD EC 1.15.1.1.) and seleno-dependent glutathione peroxidase (GSH-Px; EC 1.11.19), and two indexes of peroxidation in plasma, thiobarbituric acid reactive substances (TBARS) and organic hydroperoxides (OHP), were measured in 118 patients with insulin-dependent diabetes mellitus (IDDM), classified in accordance with the presence or absence of vascular complications and the degree of metabolic control established by the HbA1c level. Ninety healthy subjects made up the control group. According to our results, plasmatic TBARS and OHP concentrations are significantly higher in diabetics than in controls, and these differences are accentuated in diabetic people with vascular disorders. The GSH-Px activity was significantly reduced in diabetic patients with poor and medium metabolic control in relation to the control group, regardless of the existence or absence of vascular disorders. No differences in SOD activity between diabetic and control groups were found. A significant positive correlation between TBARS and HPO (r=0.683, p<0.001) was found in both the control and diabetic groups. Among the lipid parameters studied, there were only significantly positive correlations between TBARS and total cholesterol; TBARS and tryglicerides; OHP and total cholesterol and OHP and tryglicerides. Positive correlations between TBARS and HbA1c and between OHP and and HbA[sub 1c], and negative correlations between GSH-Px and HbA[sub 1c] and between SOD and HbA1c were also found. The multiple regression analysis shows that TBARS and HPO correlate negatively with GSH-Px. There was no significant correlation with SOD. [ABSTRACT FROM AUTHOR]