Procena uticaja nanoemulzifikacije, antioksidanata i temperature na oksidativnu stabilnost ulja semena maline za primenu na koži

In the past twenty years plant oils derived from food industry byproducts have been in focus due to the ecological and economic reasons. For example, raspberry seed oil – RSO (Rubus idaeus, Rosaceae), abundant with bioactive compounds such as polyunsaturated fatty acids, carotenoids, tocopherols and phenolic compounds, is recommended for antioxidant and UV-protective skincare (1). RSO application is limited by poor oxidative stability, thus this research aimed at its stabilization with nanoemulsion – NE carrier. Firstly, total carotenoid and phenolic content of RSO was determined, followed by determination of its oxidative status by tracking relevant parameters (peroxide value – PV, p-anisidine value – PA, and thiobarbituric reactive substances – TBARS) (2) during one month of storage. NEs were prepared with the polyglycerol ester-based natural surfactants by employing phase inversion composition method, with or without RSO and antioxidants: synthetic (butylated hydroxytoluene – BHT or ethylenediaminetetraacetic acid, disodium salt – Na 2EDTA), or sessile oak acorn extract (Quercus petraea, Fagaceae). NEs' physiochemical characterization included droplet size distribution analysis, electrical conductivity and pH value measurements, followed by measurement of primary and secondary oxidation products (lipid hydroperoxides – LH and TBARS, respectively). It was found that RSOs' oxidative stability was significantly improved when stored at refrigerator after opening or by adding BHT (PV˂10, PA˂6, % INH TBARS >80%). NEs were semitransparent (with very small droplets ˂70 nm) and stable at 25 and 40ºC, while drastic formation of oxidative products was avoided by employing BHT or Na2EDTA, or by using oak extract as natural stabilizer.U poslednjih dvadeset godina, usled ekoloških i ekonomskih razloga u fokusu istraživanja su biljna ulja koja se dobijaju od nusproizvoda prehrambene industrjje. Na primer, ulje semena maline (Rubus idaeus, Rosaceae), koje obiluje bioaktivnim sastojcima kao što su polinezasićene masne kiseline (linolna i linolenska), karotenoidi, tokoferoli i fenolna jedinjenja, preporučuje se za negu,antioksidativnu i UV-zaštitu kože (1). Primenu ulja maline ograničava loša oksidativna stabilnost, te je cilj ovog istraživanja bila njegova stabilizacija primenom nanoemulzije (NE), i/ili antioksidanata. Prvo je određivan sadržaj ukupnih karotenoida i fenola, a zatim oksidativni status ulja maline praćenjem relevantnih parametara (peroksidni broj – PB, p-anisidinski broj – PA i sadržaj reaktivnih supstanci tiobarbiturne kiseline – TBARS) (2), tokom mesec dana čuvanja. NEs su pripremljene na bazi novijih prirodnih poliglicerilskih estara pomoću metode inverzije faza, bezili sa dodatkom ulja semena maline i antioksidanata: sintetskih (butilhidroksitoluen – BHT ili dinatrijumova so etilendiamintetrasirćetne kiseline – Na 2EDTA), ili prirodnog ekstrakta žira hrasta kitnjaka (Quercus petraea, Fagaceae). Fizičkohemijska karakterizacija NEs izvršena je analizom distribucije veličina kapi, merenjem električne provodljivosti i pH vrednosti, te određivanjem primarnih i sekundarnih produkata oksidacije (lipidnih hidroperoksida – LH i TBARS supstanci, redom). Nađeno je da se oksidativna stabilnost ulja maline značajno poboljšala čuvanjem u frižideru nakon otvaranja ili dodatkom BHT-a (PB˂10, PA˂6, % INH TBARS >80%). Dobijene NEs su bile polutransparentne (usled malih veličina kapi ˂70 nm) i stabilne na 25 i 40ºC, a drastičan porast oksidacionih produkata je uspešno inhibiran upotrebom BHT-a ili Na 2 EDTA, kao i pomoćuekstrakta hrasta kitnjaka kao potencijalnog prirodnog stabilizatora.VIII Kongres farmaceuta Srbije sa međunarodnim učešćem, 12-15.10.2022. Beogra

Termodinamika micelizacije heksadeciltrimetilamonijum-bromida u smeši propilen-glikol-voda - konduktometrijsko ispitivanje

Micellization of hexadecyltrimethylammonium bromide (syn. cetyltrimethylammonium bromide, CTAB) in propylene glycol-water (30% v/v) binary mixture, as well as the thermodynamic properties of the resulting micelles, were investigated by electrical conductivity measurements. The conductivity data were used to determine both the critical micellar concentration (CMC) and the micellar ionization degree (∞) of CTAB in the temperature range 298.2-310.2 K. The equilibrium model of micelle formation was applied in order to obtain the thermodynamic parameters (the standard molar Gibbs free energy, ∆Gmº, enthalpy, ∆Hm0 and entropy, ∆Smº) of the micellization process. The values of ∆Gmº and ∆Hmº were found to be negative at all investigated temperatures, while the values of ∆Smº were positive and became more positive as temperature increased. A linear dependence between ∆Smº and ∆Hmº, i.e. an enthalpy-entropy compensation effect, was observed.Konduktometrijski je ispitivana micelizacija heksadeciltrimetilamonijum-bromida (sinonim cetiltrimetilamonijum-bromid, CTAB) u binarnoj smeši propilen-glikol-voda (30%, v/v), kao i termodinamičke osobine nastalih micela. Merenjem specifične provodljivosti određeni su kritična micelarna koncentracija (KMK) i stepen jonizacije micele (∞) CTAB u opsegu temperatura 298,2-310,2 K određeni su. Primenom ravnotežnog modela za proces micelizacije izračunati su termodinamički parametri: promena standardne molarne Džibsove slobodne energije, (∆Gmº), entalpije (∆Hmº) i entropije (∆Smº) micelizacije. Vrednosti ∆Gmº i ∆Hmº su bile negativne na svakoj od ispitivanih temperatura, dok su vrednosti ∆Smº bile pozitivne i povećavale su se sa porastom temperature. Na osnovu linearne zavisnosti između ∆Hmº i ∆Smº utvrđen je tzv. entalpijsko-entropijski kompenzacioni efekat

THERMODYNAMICS OF MICELLIZATION OF HEXADECYLTRIMETHYLAMMONIUM BROMIDE IN PROPYLENE GLYCOL-WATER MIXTURE: A CONDUCTIVITY STUDY

Micellization of hexadecyltrimethylammonium bromide (syn. cetyltrimethylammonium bromide, CTAB) in propylene glycol-water (30% v/v) binary mixture, as well as the thermodynamic properties of the resulting micelles, were investigated by electrical conductivity measurements. The conductivity data were used to determine both the critical micellar concentration (CMC) and the micellar ionization degree (a) of CTAB in the temperature range 298.2-310.2 K. The equilibrium model of micelle formation was applied in order to obtain the thermodynamic parameters (the standard molar Gibbs free energy, DGm0, enthalpy, DHm0 and entropy, DSm0) of the micellization process. The values of DGm0 and DHm0 were found to be negative at all investigated temperatures, while the values of DSm0 were positive and became more positive as temperature increased. A linear dependence between DSm0 and DHm0, i.e. an enthalpy-entropy compensation effect, was observed. TERMODINAMIKA MICELIZACIJE HEKSADECILTRIMETILAMONIJUM-BROMIDA U SMEŠI PROPILEN-GLIKOL-VODA: KONDUKTOMETRIJSKO ISPITIVANJE Konduktometrijski je ispitivana micelizacija heksadeciltrimetilamonijum-bromida (sinonim cetiltrimetilamonijum-bromid, CTAB) u binarnoj smeši propilen-glikol-voda (30%, v/v), kao i termodinamičke osobine nastalih micela. Merenjem specifične provodljivosti određeni su kritična micelarna koncentracija (KMK) i stepen jonizacije micele (a) CTAB u opsegu temperatura 298,2-310,2 K određeni su. Primenom ravnotežnog modela za proces micelizacije izračunati su termodinamički parametri: promena standardne molarne Džibsove slobodne energije, (DGm0), entalpije (DHm0) i entropije (DSm0) micelizacije. Vrednosti DGm0 i DHm0 su bile negativne na svakoj od ispitivanih temperatura, dok su vrednosti DSm0 bile pozitivne i povećavale su se sa porastom temperature. Na osnovu linearne zavisnosti između DHm0 i DSm0 utvrđen je tzv. entalpijsko-entropijski kompenzacioni efekat

Zinc Complex of 3-Hydroxyflavone: Spectrophotometric Determination and their Antioxidative Profiles

Flavonoids, widely distributed second metabolites of plants, have a large number of functions. Nowadays, with more nature-oriented lifestyle, the role in plants and potential benefits for humans and animals became more and more important.1 3-Hydroxyflavone (3HF) represents the backbone of all flavonols, a widespread class of flavonoids. Interestingly, this compound is not found naturally in plants. Regardless, 3HF is commonly applied as a model molecule because it possesses an excited-state intramolecular proton transfer effect and may serve as a fluorescent probe in studies of either membranes or intermembrane proteins. It has also been shown that 3HF inhibits metastasis of human osteosarcoma cells and reduces tumor growth in vivo. With aim to find wider application of 3HF, its complexes with metal ions attract the attention of the researchers. Beside the characterization of zinc complex with 3HF, we reported the validation of the developed simple and low-cost spectrophotometric determination of 3-hydroxyflavone based on its zinc complex. Furthermore, the antioxidant capacities of the synthesized complex and 3HF itself were tested by the DPPH method, followed by the evaluation of more positive issues of zinc 3HF complex. The results of the performed study highlighted the suitability of zinc complex 3HF both for spectrophotometric determination, as well as to explore future applications of its potent bioactivity

Calculation of the fraction of pseudo-capacitance and electric double layer capacitance in carbon-based electrochemical capacitors.

Novi materijali za primenu u elektrohemijskim kondenzatorima razvijaju se u različitim pravcima: ugljenične nanocevi, grafen, aktivirani ugljenici, templirani porozni ugljenici, a sve sa ciljem poboljšanja njihovih karakteristika kroz povećanje kapaciteta dvojnog električnog sloja i/ili pseudokapacitivnih faradejskih procesa. Cilj ovog rada bio je određivanje kapaciteta za seriju ugljeničnih materijala metodom ciklične voltametrije pri različitim brzinama polarizacije, kao i razdvajanje doprinosa dvojnog električnog sloja i pseudokapacitivnosti ukupnoj vrednosti kapaciteta elektrohemijskih kondenzatora. Ispitivani materijali uključuju: karbonizovani nanostrukturni polianilin (C-PANI), karbonizovani polianilin dopiran 2,2-difenil-1-pikrilhidrazilom (C-DPPH) i aktivni ugalj (AC). Njihove karakteristike ispitane su u 6M KOH i 0,5M H2SO4, a kapacitivna svojstva pomenutih materijala uspešno su razdvojena primenom Trasatijeve (Trasatti) i Danove (Dunn) metode. Pokazano je da aktivni ugalj, bez obzira što nema najveću vrednost specifičnog kapaciteta u svim elektrolitima, ipak ima najveću retenciju kapaciteta i da bi bio najpogodniji za primenu kao elektrodni materijal u odnosu na ispitivane materijale.New materials for use in electrochemical capacitors are being developed in different directions: carbon nanotubes, graphene, activated carbon, templated porous carbon, all with the aim of improving their properties by increasing the capacitance of the double electric layer and/or pseudocapacitive faradaic processes. The aim of this work was to determine the capacitance of a series of carbon materials using cyclic voltammetry at different polarization rates, as well as to separate the contribution of the electric double layer capacitance and pseudo-capacitance to the total value of the capacitance. Materials that were tested include: carbonized nanostructured polyaniline (C-PANI), carbonated polyaniline doped with 2,2-diphenyl-1-picrylhydrazyl (C-DPPH) and activated carbon (AC). Their characteristics were tested in 6M KOH and 0.5M H2SO4, and the capacitance properties of the mentioned materials were successfully separated using Trasatti and Dunn methods. It has been shown that among the tested materials, activated carbon has the highest capacity retention, and it would be the best suited for use as electrode material, although it doesn't have the highest specific capacitance value in all electrolytes

Spektrofotometrijsko određivanje sadržaja morina u jagodama i njihove antioksidantne aktivnosti

Morin is one of the flavonoids with intensive antioxidant activity. With the aim to use its benefits on human health, there is an increasing trend to pay attention to its content in food or supplements. The simplicity and low cost of spectrophotometric determination based on the formation of a morin complex with Zn2+ ion (stoichiometric ratio 1 : 1), at pH 7.98 and 392 nm, give it an advantage over other methods that can be used for morin quantification. The concentration range over which the response was linear was 0.151 – 4.533 mg L-1. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.030 mg L-1 and 0.091 mg L-1, respectively. The developed method was successfully applied for the determination of the morin content in strawberries. Additionally, the antioxidative abilities of strawberry extracts and morin, determined by DPPH and FRAP tests, were compared and discussed.Morin je jedan od flavonoida sa vrlo izraženom antioksidantnom aktivnošću. Sa ciljem korišćenja njegovih pozitivnih efekata na ljudsko zdravlje, u porastu je trend interesovanja za njegov sadržaj u hrani ili suplementima. U radu je predstavljena jednostavna i pristupačna spektrofotometrijska metoda određivanja morina, zasnovana na formiranju kompleksa morina sa Zn2+ jonom (u stehiometrijskom odnosu 1 : 1, na pH 7,98 i 392 nm), što joj daje prednost u odnosu na druge metode koje se mogu koristiti za kvantifikaciju morina. Metoda pokazuje linearnost odgovora u koncentracionom opsegu 0,151 - 4,533 mg L-1, pri čemu limit detekcije (LOD) iznosi 0,030 mg L-1 a limit kvantifikacije metode (LOQ) je 0,091 mg L-1. Razvijena metoda je uspešno primenjena za određivanje sadržaja morina u jagodama. Takođe, prikazani su i komentarisani rezultati određivanja antioksidativne aktivnosti jagoda i morina, DPPH i FRAP testovima

Uporedno spektrofotometrijsko određivanje 3-hidroksiflavona bazirano na kompleksima cinka i aluminijuma i njihovi antioksidatni profili

Abstract Flavonoids, as plant-derived compounds, were essential active components in traditional medicine for centuries. Their potential or confirmed effects include antiviral, antimutagenic, antiinflammatory, antibacterial, vasodilatory, and anticancer properties. The promotion of a plantbased diet, along with the benefits of consuming flavonoids, has recently become increasingly attractive. 3-Hydroxyflavone (3HF) is the structural spine of flavonols, an important subgroup of flavonoids. Although 3HF itself does not exist in plants per se, it exerts many of its effects because of its characteristics that allow it to prevent free radical generation. This work is focused on the characterization of 3HF complexes with zinc(II) and aluminium(III) ions (Zn-3HF and Al-3HF, respectively). Besides this, a simple, fast, and low-priced spectrophotometric method for 3HF determination, with very low LOD and LOQ, based on Zn-3HF and Al-3HF formation, was established. A slight advantage is given to the modification with Al3+ ion on pH 4.91, due to very low LOD and LOQ values of 1.83×10-7 molL-1 , and 5.50×10-7 molL-1 , respectively, and a high correlation coefficient, R =0.99986. Furthermore, the antioxidant ability of Zn-3HF, Al-3HF, and parent 3HF was examined by the ABTS and DPPH tests. They brought the Zn-3HF complex to the fore as a potential antioxidative agent.Flavonoidi, jedinjenja biljnog porekla, vekovima su bili veoma važne aktivne komponente u tradicionalnoj medicini. Veliki broj njihovih potencijalnih ili već potvrđenih efekata uključuje antivirusna, antimutagena, antiinflamatorna, antibakterijska, vazodilatatorna i antikancerogena svojstva. Promovisanje biljne ishrane, uz isticanje koristi konzumiranja flavonoida, u današnje vreme postalo je sve privlačnije. 3-Hidroksiflavon (3HF) je strukturni stub svih flavonola, važne klase flavonoida. Iako sam 3HF ne postoji u biljkama per se, on ispoljava mnoge svoje efekte zahvaljujući osobini da sprečava stvaranja slobodnih radikala. Ovaj rad je fokusiran na karakterizaciju kompleksa 3HF sa jonima cinka(II) i aluminijuma(III) (Zn-3HF i Al-3HF, respektivno). Izvršena je karakterizacija ovih kompleksa i razvijena brza i pristupačna metoda za spektrofotometrijsko određivanje 3HF, na osnovu formiranja kompleksa Zn-3HF i Al-3HF, sa veoma niskim vrednostima LOD i LOQ. Mala prednost je data modifikaciji sa Al3+ na pH 4,91 zbog izuzetno niskih vrednosti LOD i LOQ, 1,83×10-7 mol L-1 , odnosno 5,50×10-7 mol L-1 , kao i visokog koeficijenta korelacije, R=0,99986. Pored toga, antioksidativni kapaciteti sintetizovanih kompleksa Zn-3HF i Al-3HF, kao i samog 3HF, ispitani su DPPH i ABTS testovima i doveli su Zn-3HF kompleks u prvi plan za dalja ispitivanja kao potencijalnog antioksidativnog agensa

Electrochemical Sensing of Cadmium and Lead Ions in Water by MOF-5/PANI Composites

For the first time, composites of metal-organic framework MOF-5 and conjugated polymer polyaniline (PANI), (MOF-5/PANI), prepared using PANI in its conducting (emeraldine salt, ES) or nonconducting form (emeraldine base, EB) at various MOF-5 and PANI mass ratios, were evaluated as electrode materials for the electrochemical detection of cadmium (Cd2+) and lead (Pb2+) ions in aqueous solutions. Testing of individual components of composites, PANI-ES, PANI-EB, and MOF-5, was also performed for comparison. Materials are characterized by Raman spectroscopy, scanning electron microscopy (SEM) and dynamic light scattering (DLS), and their electrochemical behavior was discussed in terms of their zeta potential, structural, morphology, and textural properties. All examined composites showed high electrocatalytic activity for the oxidation of Cd and Pb to Cd2+ and Pb2+, respectively. The MOF/EB-1 composite (71.0 wt.% MOF-5) gave the highest oxidation currents during both individual and simultaneous detection of two heavy metal ions. Current densities recorded with MOF/EB-1 were also higher than those of its individual components, reflecting the synergistic effect where MOF-5 offers high surface area for two heavy metals adsorption and PANI offers a network for electron transfer during metals’ subsequent oxidation. Limits of detection using MOF/EB-1 electrode for Cd2+ and Pb2+ sensing were found to be as low as 0.077 ppm and 0.033 ppm, respectively. Moreover, the well-defined and intense peaks of Cd oxidation to Cd2+ and somewhat lower peaks of Pb oxidation to Pb2+ were observed at voltammograms obtained for the Danube River as a real sample with no pretreatment, which implies that herein tested MOF-5/PANI electrodes could be used as electrochemical sensors for the detection of heavy metal ions in the real water samples

МИЦЕЛАРНИ СВОЈСТВА НА ЦЕТИЛТРИМЕТИЛАМОНИУМ БРОМИД ВО СМЕСАТА ОД АЦЕТОНИТРИЛ ВОДА: КОНДУКТОМЕТРИСКИ И ФЛУОРЕСЦЕНТНИ СТУДИИ

The effect of acetonitrile (ACN) on the micellization of a cationic surfactant, cetyltrimethylammo-nium bromide (CTAB), in aqueous solutions at different temperatures was studied. The critical micellar concentration (CMC) as well as the degree of counter ion dissociation () of CTAB in aqueous ACN mixtures (1020 % v/v) at various temperatures (291.2298.2 K) were determined by electrical conduc-tivity measurements, while steady-state fluorescence measurements were used to determine several CMCs (for comparison) and a micellar aggregation number (Nagg) as well. At a fixed temperature, both an increase in CMC and a decrease in Nagg were observed for an increase in ACN in the solvent mixture. With a temperature increase, CMC values increased for 10 % (v/v) ACN, while for both 15 % and 20 % (v/v) ACN, CMC values were a minimum at T = 295.2 K with a temperature increase. In addition, some aspects related to the Krafft temperature behavior of CTAB in the examined micellar systems are dis-cussed.Беше испитано влијанието на ацетонитрилот (ACN) врз мицелизацијата на катјонски сурфактант, цетилтриметиламониум бромид (CTAB), во водна средина на различни температури. Со помош на мерења на електричната спроводливост, беа определени критичната мицеларна концентрација (CMC), и степенот на дисоцијација на спротивните јони () на CTAB во водни смеси на ACN (1020 % v/v) на различни температури (291,2298,2 K), додека за определување на неколку CMC (за споредба), како и на мицеларен агрегационен број (Nagg) беа употребени рамнотежни флуоресцентни мерења. На фиксна температура беше забележано зголемување на CMC и намалување на Nagg со зголемување на ACN во смесата на растворот. Со зголемување на температурата вредностите на CMC се зголемија за 10 % (v/v) ACN, додека за 15 % и за 20 % (v/v) ACN, вредностите на CMC при зголемување на температурата на T = 295,2 K беа минимални. Покрај тоа, дискутирани се некои аспекти што се поврзани со однесувањето на температурата на Krafft на CTAB во испитуваните мицеларни системи

АНТИОКСИДАТИВЕН КАПАЦИТЕТ И АНТИМИКРОБНИ ЕФЕКТИ НА КОМПЛЕКСИ НА ЦИНК СО ФЛАВОНОИДИ – ДАЛИ ПОСТОИ СИНЕРГИЗАМ?

The presence of residual cardiovascular disease (CVD) risk is a current dilemma in clinical practice; indeed, despite optimal management and treatment, a considerable proportion of patients still undergo major CV events. Novel lipoprotein biomarkers are suggested as possible targets for improving the outcomes of patients at higher risk for CVD, and their impact on major CV events and mortality have previously been investigated. Innovative antidiabetic therapies have recently shown a significant reduction in atherogenic lipoproteins, beyond their effects on glucose parameters; it has also been suggested that such anti-atherogenic effect may represent a valuable mechanistic explanation for the cardiovascular benefit of, at least, some of the novel antidiabetic agents, such as glucagon-like peptide-1 receptor agonists. This emphasizes the need for further research in the field in order to clearly assess the effects of innovative treatments on different novel biomarkers, including atherogenic lipoproteins, such as small dense low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and dysfunctional high-density lipoprotein (HDL). The current article discusses the clinical importance of novel lipid biomarkers for better management of patients in order to overcome residual cardiovascular risk.Постои постојана потреба од ефикасни лекови, комбинации на лекови и методи за спречување на бактериски и вирусни инфекции, вклучувајќи го и коронавирусот. Познато е дека улогата на елементи во траги во зајакнување на човековиот имун систем е значајна. Витамините, микроелементите, вклучувајќи цинк, железо, селен, магнезиум и бакар, масните киселини омега-3 играат значајна физиолошка улога во унапредување на имуниот систем. Цинкот е неопходен микроелемент за основните ензимски физиолошки процеси. Тој игра важна улога во делбата на клетките и е вклучен во развојот на клетки одговорни за неспецифичен имунитет. Познато е дека недостигот на цинк ги предиспонира пациентите на вирусни инфекции поради намалениот антивирусен имунитет. Од друга страна, флавоноидите како метаболити на растенијата играат важна улога во спречување на оксидативен стрес. Овој труд има за цел да ја дискутира in vitro улогата на цинкот, флавонидите и нивните комплекси, како и нивните антиоксидативни и антимикорбни активности. Разгледана е и оправданоста за истовремена употреба на цинк и флавоноиди