Antioxidative and Antiradical Activity of Flavonoids

Flavonoidi u posljednje vrijeme privlače puno pozornosti zbog svoje izvanredne antioksidacijske i antiradikalske aktivnosti. Istraživanja su pokazala da su flavonoidi dobri “hvatači” slobodnih radikala, a time imaju važnu ulogu u farmaceutskoj i prehrambenoj industriji kao lijekovi i antioksidansi. Flavonoidi imaju i širok niz drugih biokemijskih funkcija. Oni su možda najkorisnije fitokemikalije pronađene u hrani. Poznati su i sinergijski efekti kod antioksidacijskog djelovanja flavonoida. Pokazalo se da flavonoidi imaju antibakterijsko, sedativno, antialergijsko, antimutageno, antiviralno i druga djelovanja.Flavonoids are a major group of phenolic compounds which are important in flavouring and colouring of many fruits and vegetables and derived products such as wine, tea preparations and chocolate. Recently, flavonoids are given much attention due to their excellent antioxidative and antiradical activity. Studies have revealed that flavonoids are good scavengers of free radicals, and consequently, they are much used in pharmaceutical and food industries. Flavonoids also have a gamut of other biochemical activities; some have been found to possess significant anti-cardiovascular disease, anti-inflammatory, anti-allergic, anti-mutagenic, antiviral, anti-tumour and activities

Ligacija U+ u plinskoj fazi. Usporedba pirena, fenantridina i fenantrena kao liganada

Ligation of U+ with phenanthrene in an FT ICR MS instrument is compared with previous results on U+ with pyrene and phenanthridine. All investigated processes compete with U+ oxidation by water and oxygen traces in the instrument. The comparison indicates that oxidation preferentially involves dehydrogenated ligation products.Ligacija U+ fenantrenom u FT ICR spektrometru masa uspoređuje se s ranijim rezultatima na U+ s pirenom i fenantridinom. Svi istraženi procesi su u kompeticiji s oksidacijom U+ tragovima vode i kisika u instrumentu. Usporedba pokazuje da oksidacija preferira dehidrogenirane produkte ligacije

Gas phase kinetics of metal ion ligation by pyrene

Investigation of simple ligation reactions of metal M+ ions with pyrene (Py) within the ICR FT mass spectrometer indicates relatively fast consecutive formation of MPy+ and MPy2+ ions, and if E-i(M+) > E-i(Py) accompanied also by formation of Py+ due to charge exchange. The much slower reaction and equilibrium Py+ + Py reversible arrow Py-2(+), for which the thermodynamic parameters are known, makes it possible to determine the concentration of Py during the ligation reactions and to calculate the second order rate constants from the set of pseudo first order constants obtained by iterative nonlinear least square fitting of experimental snapshot mass spectral data with the proposed kinetic scheme

Kinetike ligacije metalnih monokationa s pirenom u plinskoj fazi

The gas-phase ligation of M+ ions with pyrene is reviewed. The M+ (M = Al, K, V, Cr, Fe, Co, Ni, Cu, Nb, Mo, Ru, Ag, Sn, Ta, W, Re, Pt, Au, Hg, Pb, Bi and U) were produced by a single laser shot. Gaseous pyrene was already present in the Fourier transform mass spectrometer (FTMS). The reaction proceeded by consecutive ligations, sometimes accompanied by expulsion of a part (usually H2) of the ligand. Charge transfer (when the neutral metal has a higher ionization energy than the pyrene), pyrene dimerization, oxidation by residual oxygen, and protonation by ubiquitous water in the instrument may also take place. Reaction progression was followed by varying the delay time between the shot and the mass-spectrometric assay of the ions. If electronically-excited M+, which might have been produced by the laser pulse, was interfering with the reaction, these ions and their products were swept out of the FTMS chamber prior to initiation of the time delay specified above.Istraživana je ligacija različitih metalnih monokationa M+ s pirenom u plinskoj fazi. M+ (M = Al, K, V, Cr, Fe, Co, Ni, Cu, Nb, Mo, Ru, Ag, Sn, Ta, W, Re, Pt, Au, Hg, Pb, Bi and U) nastaju pojedinačnim udarima lasera na metalne mete unutar spektrometra masa uz Fourierovu transformaciju (FTMS) u kojem je već prisutan piren u plinskoj fazi. Do ligacije dolazi konsekutivnim adicijama uz ili bez gubitka dijela (obično H2) liganda. Ukoliko je energija ionizacije metala veća od energije ionizacije pirena dolazi do izmjene naboja. Također se opažaju reakcije dimerizacije, oksidacije s preostalim kisikom i protoniranje s prisutnom vodom u instrumentu. Napredovanje reakcija je praćeno snimanjem svih iona uz različita vremena zadržavanja u spektrometru nakon (i) udara lasera; (ii) dodatnoga izbacivanja trenutno stvorenih produkata s elektronički pobu|enim M+

Sastav mikroflore sirovog kravljeg mlijeka i identifikacija enterokoka primjenom MAL DI-TOF MS - kratko priopćenje.

Raw milk consumption could present a potential risk for public health due to the presence of foodborne pathogens and spoilage bacteria. In this research, microbiota or raw cow’s milk was studied with particular reference to the presence of enterococcal opportunistic pathogens. Total viable count, psychrophilic bacteria, lactic acid bacteria, staphylococci, Escherichia coli, enterococci, enterobacteria, Listeria spp. and sulfitereducing clostridia were evaluated using standard culture methods. Milk samples originated from healthy (n = 17) and antibiotic-treated cow’s udders (n = 19). Presumptive enterococci (n = 43) were randomly selected from chromogenic media and subjected to phenotypic identification by API 20 Strep, followed by Matrix- Assisted Laser Desorption Ionization - Time of Flight Mass Spectometry (MALDI-TOF MS). Statistically significant differences (P<0.05) regarding the udder status were found in the total viable count and lactic acid bacteria. MALDI-TOF MS determination showed 100% concordance with API 20 Strep in the identification of Enterococcus faecalis. Strains determined to the genus level only, or non-determined strains by API 20 Strep were successfully identified using MALDI-TOF MS to the strain level as E. faecalis, E. faecium and E. durans. Results showed that MALDI-TOF MS could be applied as a reliable method in the routine identification of enterococcal species from raw milk.Konzumiranje sirovog mlijeka može predstavljati potencijalni rizik za potrošače uslijed prisutnosti patogenih bakterija i bakterija kvarenja. U ovom radu istražen je sastav mikroflore sirovog kravljeg mlijeka s posebnim naglaskom na prisutnost enterokoka. Određivan je ukupni broj bakterija, psihrofilnih bakterija, bakterija mliječne kiseline, stafilokoka, Escherichia coli, enterokoka, enterobakterija, Listeria spp. i sulfitreducirajućih klostridija primjenom standardnih mikrobioloških metoda. Mlijeko je potjecalo od zdravih krava (n = 17) i krava s liječenim mastitisom (n = 19). Kolonije enterokoka (n = 43) su nasumično odabrane sa selektivne podloge te podvrgnute fenotipskoj identifikaciji pomoću API 20 Strep, a potom MALDI-TOF masenom spektrometrijom. Statistički značajne razlike (P<0,05) s obzirom na zdravstveni status vimena zabilježene su u ukupnom broju bakterija i bakterija mliječne kiseline. Rezultati identifikacije izolata Enterococcus faecalis bili su u potpunom suglasju primjenom MALDI-TOF MS i API 20 Strep. MALDI-TOF MS tehnikom identificirani su izolati enterokoka koje API 20 Strep sustavom nije bilo moguće identificirati ili su bili identificirani do razine roda. Rezultati istraživanja pokazuju da se MALDI-TOF MS može smatrati pouzdanom metodom u rutinskoj identifikaciji enterokoka iz sirovog mlijeka

On the Proton Affinity of Peroxynitrite and Peroxynitrous Acid

The proton affinity (PA) of peroxynitrite (ONOO-) and peroxynitrous acid (ONOOH) are calculated to be 1440.5 kJ mol-1 and 749.8 kJ mol-1, respectively. Comparison with results for the nitrous, nitric and peroxynitric acid and their anions supports these estimates