Slavoljub Živanović

Chemical profile and antioxidative and antimicrobial activity of juices and extracts of 4 black currants varieties (Ribes nigrum L.).

UNLABELLED The aim of this article was to determine the chemical composition (anthocyanin and ascorbic acid contents, total phenols, and tannins), and the antioxidative, and antimicrobial activities of the juices and methanol extracts of 4 varieties-Tenah, Triton, Ben Sarek, and Ometa. The juices were made during 2008, 2009, and 2010 from the berries grown on the same location. Statistically significant differences were found in all the tested parameters of each variety for every year. Ometa variety exhibited the best antioxidative activity. The highest ascorbic acid value had Tenah juice from 2010 (211 mg/100 g) and Ben Sarek methanol extract (656 mg/100 g). Delphinidin-3-ruthenoside was the dominant anthocyanin in Triton, Tenah, and Ben Sarek variety during all 3 y and Ometa in 2010 where Ometa in 2008 and 2009 had slightly higher content of cyanidin-3-ruthenoside. The minimum inhibitory and microbicidal concentrations ranged from MIC/MBC(MFC) = 62.5 to 500 mg/mL for juices and 0.4 to 500 mg/mL for extracts. There was no significant difference in the effect of the juices against Gram(+) and Gram(-) bacteria. All the extracts acted in lower concentrations than juices. PRACTICAL APPLICATION Data contained in this article provide an insight into the effects the weather condition has on the content of the bioactive compounds in genetically different types of black currants, during the 3-y observation period. This article is relevant to the commercial application of black currants-based dietary supplements.

Dimethylarginine – biomarkers in progression of kidney disease / Dimetilarginini – biomarkeri u progresiji bubrežnih oboljenja

Summary Decreased nitric oxide (NO) production and/or impaired NO bioavailability may occur in patients with the chronic kidney disease (CKD), and could contribute to elevation of blood pressure, cardiovascular disease (CVD) and progression of renal injury in these patients. Free guanidinomethylated arginine residues occur endogenously as a result of proteolysis of post-translational methylated tissue proteins. The asymmetric dimethyl arginine (ADMA) is a competitive inhibitor of the nitric oxide synthase (NOS) enzymes. The kidney has a predominant role in ADMA elimination by combining two mechanisms; urinary excretion and metabolization of ADMA The degradation of ADMA is accomplished intracellularly by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). ADMA is not only a uremic toxin, but also a strong marker of the endothelial dysfunction and atherosclerosis and a stronger independent predictor of all-cause mortality and cardiovascular outcome in patients with the chronic renal failure. There are at least four mechanisms that may explain the accumulation of ADMA in CKD: increased methylation of proteins, increased protein turnover, decreased metabolism by DDAH and impaired renal excretion. A strong positive correlation between symmetric dimethyl arginine (SDMA) and creatinine suggests that SDMA might be of value as a marker of the renal function. Reduced NO elaboration secondary to accumulation of ADMA and elevated inflammation may be important pathogenic factors for endothelial dysfunction in patients with the renal disease. Elevation of ADMA may be a missing link between CVD and CKD. Kratak sadržaj Smanjenje koncentracije NO i/ili nedovoljna raspolo`ivost ovog molekula kod pacijenata sa bubre`nim bolestima mo`e biti razlog pove}anja krvnog pritiska, kardiovaskularnih bolesti (KVS) i progresije bubre`nog o{te}enja. Metilarginini nastaju u procesu proteolize posttranslaciono metilisanih argininskih rezidua u proteinima. Asimetri~ni dimetilarginin (ADMA) je kompetitivni inhibitor azot oksid sintaze (NOS). Najva`nija uloga bubrega u eliminaciji ADMA podrazumeva procese urinarne ekskrecije i razgradnju pod uticajem dimetilarginin dimetilaminohidrolaze (DDAH). Na aktivnost DDAH uti~u oksidativni stres i inflamacija. ADMA nije samo uremijski toksin ve} i zna~ajan marker endotelne disfunkcije i ateroskleroze, kao i nezavisni prediktor mortaliteta i kardiovaskularnih bolesti kod pacijenata sa HBI. Osnovni uzroci koji dovode do akumulacije ADMA su pove}ana metilacija proteina, njihov pove}an metabolizam, smanjena aktivnost DDAH i smanjena urinarna ekskrecija. Klirens simetri~nog dimetilarginina (SDMA) u plazmi zavisi samo od renalne funkcije (pozitivna korelacija sa kreatininom) i njena akumulacija predstavlja nespecifi~ni indikator uremijskih toksina. Redukovana koli~ina NO pra}ena akumulacijom ADMA, udru`ena sa inflamacijom mo`e biti va`an patogeni faktor endotelne disfunkcije kod bubre`nih pacijenata. Porast koncentracije ADMA mo`e biti veza izme|u KVS i HBI.

Anti-inflammatory effect of the Salvia sclarea L. ethanolic extract on lipopolysaccharide-induced periodontitis in rats

ETHNOPHARMACOLOGICAL RELEVANCE Salvia sclarea L., clary, is an aromatic plant traditionally used in folk medicine for the treatment of various diseases and conditions. Although it has been primarily used as a stomachic, there are data on traditional use of S. sclarea as an agent against gingivitis, stomatitis and aphthae. AIM OF THE STUDY The aim of the study was to examine the effect of the S. sclarea ethanolic extract on the lipopolysaccharide (LPS)-induced periodontitis in rats from the immunological and histopathological standpoint. MATERIAL AND METHODS Periodontal inflammation in rats was induced by repeated injections of LPS from Escherichia coli into the interdental papilla between the first and second right maxillary molars. The extract was administered two times a day by oral gavage (200mg/kg body weight). The inflammatory status was assessed by the measurements of proinflammatory cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) of gingival tissues and descriptive analysis of histological sections of periodontium. Chemical characterization of the extract was determined using high performance liquid chromatography system (HPLC). Antioxidant activity of the extract was estimated with two in vitro complementary methods: 2,2-diphenyl-1-picrylhydrazyl and β-carotene/linoleic acid models. RESULTS Treatment with S. sclarea extract, compared to the untreated group of the rats, significantly diminished the process of inflammation decreasing the levels of IL-1β, IL-6 and TNF-α, reducing the gingival tissue lesions and preserving bone alveolar resorption. Considerably smaller number of inflammatory cells and larger number of fibroblasts was noticed. The administration of the extract three days earlier did not have significant preventive effects. Rosmarinic acid was the predominant compound in the extract. The extract showed strong antioxidant effects in both test systems. CONCLUSIONS S. sclarea extract manifested anti-inflammatory effect in LPS-induced periodontitis suggesting that it may have a role as a therapeutic agent in periodontal diseases. Having in mind that overproduction of reactive oxygen species is connected to periodontitis, the strong antioxidant capacity may be contributable to anti-inflammatory properties of the extract.

The Influence of Mg(II) and Ca(II) Ions on Rutin Autoxidation in Weakly Alkaline Aqueous Solutions

Summary Rutin (quercetin-3-O-rutinoside) is one of the most abundant bioflavonoids with various biological and pharmacological activities. Considering the ubiquitous presence of Mg(II) and Ca(II) ions in biological systems we decided to investigate their influence on the autoxidation of rutin in weakly alkaline aqueous solutions. Changes in UV-Vis spectra recorded during the rutin autoxidation in aqueous solution at pH 8.4 revealed that this process was very slow in the absence of metal ions. The presence of Mg(II) and, especially Ca(II) ion, increased the transformation rate of rutin. UV-Vis spectra recorded after prolonged autoxidation indicated the formation of humic acidlike products in the presence of Mg(II) and Ca(II) ions. Four new compounds formed during the initial stage of rutin autoxidation in the presence of Mg(II) and Ca(II) ions were detected by HPLCDAD. Based on the analysis of their DAD UV-Vis spectra and comparison of their retention times with the retention time value for rutin, we concluded that the initial rutin transformation products were formed by the water addition on double bond in ring C and hydroxylation of ring B. A very small decrease of the initial rutin concentration (4%) was observed by HPLC-DAD in the absence of metal ions for the period of 90 minutes. However, rutin concentration decrease was much larger in the presence of Mg(II) and Ca(II) ions (14% and 24%, respectively). The more pronounced effect of Ca(II) ion on the rutin autoxidation may be explained by the stronger binding of Mg(II) ion to rutin and thus greater stabilizing effect on reaction intermediates caused by its higher ionic potential (charge/ionic radius ratio) in comparison to Ca(II) ion. The results of this study may contribute to the better understanding of interactions of Mg(II) and Ca(II) ions with natural phenolic antioxidants which are important for their various biological activities.

ADMA and C-reactive protein as mortality predictors in dialysis patients

There is a higher mortality between patients with end-stage renal disease than patients in the general population. These circumstances have led to a search for risk factors as predictors of mortality in dialysis patients. Amongst those, inhibitors of the nitric-oxide (NO) synthesis deserve special attention, since patients with end-stage renal disease are also characterized by accelerated atherosclerosis. Asymmetric-dimethylarginine (ADMA) and symmetric-dimethylarginine (SDMA), as well as C-reactive protein (CRP), have also been recognized as predictors of mortality in patients on dialysis. The aim of our study was to compare the prediction power of ADMA, SDMA and CRP for all-cause mortality in patients with end stage renal disease during the fourteen month follow-up. In total 162 patients on hemodialysis were included. ADMA and SDMA were measured by the high-performance liquid chromatography (HPLC); CRP was measured using immunonephelometric assays. During the 14-month period 28 patients (34.1%) died from all-cause mortality. Using univariate analysis, hazard ratios (HR) of the potential independent predictors of mortality in hemodialysis patients were ADMA (HR 1.39 (1.01–1.91) p=0.043) and CRP (HR 1.024 (1.009–1.1.040) p=0.001). Further, multivariate analysis (MVA), however, showed that ADMA is the only predictor of all-cause mortality (HR 1.76 (1.002–3.11) P=0.049), while SDMA failed to predict death in this population. Therefore, our data shows that ADMA is an independent and better marker of all-cause mortality compared with CRP.

The study of the influence of Mg(II) and Ca(II) ions on caffeic acid autoxidation in weakly alkaline aqueous solution using MCR-ALS analysis of spectrophotometric data

UV-Visible spectrophotometry was used to study the influence of Mg(II) and Ca(II) ions on caffeic acid (CA) autoxidation in weakly alkaline aqueous solution. While the autoxidation rate was very slow in the absence of metal ions, both Mg(II) and Ca(II) ions greatly enhanced the autoxidation rate. Determination of the spectral and concentration profiles of the individual components involved in the CA autoxidation processes in the presence of metal ions was performed using multivariate curve resolution-alternating least squares (MCR-ALS) analysis of spectrophotometric data. MCR-ALS analysis supported by the quantum chemical calculations of electronic absorption spectra for possible initial reaction products showed that CA autoxidation in the presence of Mg(II) and Ca(II) ions proceeds by the instant formation of CA–metal complexes followed by the almost simultaneous formation of CA quinone anions and various CA dimers and the final transformation into polymeric, humic acid-like, products. Also, the MCR-ALS analysis revealed that the effect of Mg(II) ions was more pronounced at the initial stage of autoxidation. The differences in the influence of Mg(II) and Ca(II) ions on the CA autoxidation may be attributed to the stronger metal ion–ligand interaction for Mg(II) ions caused by their larger ionic potential in comparison to Ca(II) ions. The results of this study may be important for better understanding of the interactions of Mg(II) and Ca(II) ions with natural phenolic food antioxidants and thus significant for understanding their activities in real systems and optimization of conditions for the processing and/or storage of certain types of foods.

Synthesis, spectroscopic and structural characterization of Co(II)-pullulan complexes by UV-Vis, ATR-FTIR, MALDI-TOF/TOF MS and XRD

Complexes of Co(II) ion with reduced low-molar pullulan (RLMP) (Mw 6000 g/mol) were synthesized in aqueous solutions at boiling temperature in the pH range from 7.5 to 13.5. Obtained Co(II)-RLMP complexes, with cobalt content ∼2-8% (AAS), were characterized by UV-Vis spectrophotometry, FTIR spectroscopy (ATR-FTIR, FT-IRIS), MALDI-TOF/TOF MS, and XRD. Tetragonally distorted Oh coordination of Co(II) ions with O ligand atoms in synthesized complexes is suggested based on the spectrophotometric data. No influence of complexation process on the 4C1 chair conformation of the d-glucopyranose units of pullulan was detected by ATR-FTIR measurements and FT-IRIS showed high homogeneity of synthesized complexes. Some additional depolymerization of pullulan during complex synthesis was indicated by MALDI-TOF/TOF MS but it also revealed good stability of complexes with much weaker binding of Co(II) ion in low molar mass fragments. Even in complexes with highest Co(II) ion content a low degree of crystallinity was detected by XRD analysis.