Fenolne komponente i vitamin C kao izvori antioksidativne aktivnosti ploda crne ribizle (Ribes nigrum L.)

The content of some important phenolic compounds (kaempferol, myricetin, quercetin, and ellagic acid), total phenolics (TPH), vitamin C, and total antioxidant capacity (TAC) in the fruit of three black currant cultivars (Ben Lomond, Ben Sarek and Malling Juel) were studied. The content of individual phenolic compounds showed variability among the studied cultivars. The main flavonol found in cv. Malling Juel was kaempferol (1.60 μg g-1 FW), whereas the lowest values of myricetin (5.46 μg g-1 FW) and quercetin (7.65 μg g-1 FW) were also observed in the fruit of this cultivar. Ellagic acid content was the highest in cv. Ben Lomond (12.90 μg g-1 FW), which is also characterized by lower values of individual flavonols compared to other cultivars tested. However, the highest TPH level was recorded in cv. Ben Lomond (4.71 mg g-1FW). Vitamin C content in fruit of cv. Malling Juel was at a very high level (141.4 mg 100g-1), whereas cv. Ben Lomond expressed the highest level of TAC (7.60 mg asc g-1 FW). Overall, the content and profile of phenolic compounds in the black currant cultivars showed significant contribution to the expressed antioxidant capacity which was confirmed by positive correlation between TPH and TAC obtained in this study. Besides total phenolics, vitamin C is also a significant contributor to the measured antioxidant capacity in black currant fruit indicating that some cultivars with lower phenolic content may express high TAC.Rad prikazuje rezultate trogodišnjih ispitivanja sadržaja važnih fenolnih jedinjenja (flavonola - kampferola, miricetina i kvercetina, elaginske kiseline i ukupnih fenola), vitamina C, kao i vrednosti antioksidativnog kapaciteta registrovane u plodu tri sorte crne ribizle Ben lomond, Ben sarek i Moling džuel. Istraživanja su realizovana u periodu od 2004. do 2006. godine u laboratorijama Katedre za voćarstvo Poljoprivrednog fakulteta Univerziteta u Beogradu i Instituta za multidisciplinarna istraživanja iz Beograda. Ustanovljeno je variranje u sadržaju pojedinih individualnih fenolnih komponenti između ispitivanih sorti crne ribizle, pri čemu je kod sorte Moling džuel registrovan najveći prosečni sadržaj kampferola (1,60 μg g-1), ali i najniže prosečne vrednosti sadržaja miricetina (5,46 μg g-1) i kvercetina (7,65 μg g-1). Među ispitivanim sortama crne ribizle najveći sadržaj elaginske kiseline imala je sorta Ben lomond (12,90 μg g-1), koja se odlikuje nešto nižim vrednostima sadržaja flavonola u plodu, ali i najvećim sadržajem ukupnih fenola za ispitivani period (4,71 mg g-1). U pogledu sadržaja vitamina C, sorta Moling džuel je pokazala superiornost (141,4 mg 100g-1), dok se najvećim antioksidativnim kapacitetom ploda za trogodišnji period ispitivanja odlikuje sorta Ben lomond (7,60 mg ask g-1). Na osnovu većine analiziranih parametara može se konstatovati da sadržaj i profil fenolnih komponenata prisutnih u plodovima ispitivanih sorti crne ribizle, ima značajan doprinos u ispoljenoj antioksidativnoj aktivnosti, što potvrđuje i pozitivna korelativna zavisnost između sadržaja ukupnih fenola i antioksidativnog kapaciteta ploda. Pored ukupnih fenola, značajan doprinos antioksidativnom kapacitetu ploda daje i vitamin C. To objašnjava pojavu da su neke sorte posedovale visok antioksidativni kapacitet ploda uz, istovremeno registrovan, umeren sadržaj fenolnih jedinjenja

Maternal effect of continuous light on seed properties in a short day plant Chenopodium rubrum L. (Chenopodiaceae)

Environmental effects on morphological and physiological properties of offspring which occurs during development of mother plant are called maternal environmental effects. Photoperiod is one of the crucial environmental factors according to which plants modify numerous physiological processes. Maternal effect of photoperiod in a short day plant Chenopodium rubrum extends through the whole life cycle of offspring and persist to the second generation, photoperiod during induction and evocation of flowering of mother plants showing the key influence. Here we show that also non-inductive photoperiod preceding flowering induction of mother plants shows its maternal effect on offspring properties: seed size, seed germination and seed protein composition. Presented data argues in favor of earlier suggested that relative amounts of seed proteins represent an “archive“ of photoperiods experienced by mother plants during their lives

Fizičko-hemijska i antioksidativna svojstva sorti i samoniklih vrsta rodova Fragaria i Rubus

The paper presents three years study results (2004-2006) of more important pomological properties and antioxidant capacity in the fruit of strawberry, raspberry and blackberry. A comparison was made between cultivars and wild relatives of each species (Fragaria vesca L., Rubus idaeus L., and Rubus fruticosus L.). It was found out that studied wild species expressed significantly lower values of physical fruit properties in comparison to those determined by commercial cultivars. With regard to chemical fruit composition, wild species showed better results for most of studied parameters. Total phenolics expressed higher values in the wild strawberry and blackberry in comparison to the studied cultivars, and consequently the highest levels of antioxidant capacity were recorded in F. vesca (5.78 mg g-1 FW), followed by R. fruticosus (4.95 mg g-1 FW). Concerning raspberries, the most widely grown cultivar in Serbia, 'Willamette', possessed higher antioxidant capacity than those for R. idaeus (1.41 mg ask g-1 FW). A positive correlation observed in this study between total phenolics and antioxidant capacity indicate the fact that phenolic compounds had significant contribution in expressed antioxidant activities.Rad prikazuje rezultate trogodišnjih ispitivanja važnijih pomoloških osobina i antioksidativnog kapaciteta ploda, koji su komparativno proučavani kod samoniklih vrsta jagodastih voćaka: šumske jagode (Fragaria vesca L.), samonikle maline (Rubus idaeus L.) i samonikle kupine (Rubus fruticosus L.) uzetih sa prirodnih staniš ta i kod dve komercijalno značajne sorte svake pomenute vrste: jagode (Marmolada i Madlen), maline (Willamette i Meeker) i kupine (Thornfree i Čačanska bestrna). Ustanovljeno je da su među fizičkim osobinama ploda, značajno niže vrednosti mase i dimenzija ploda ispoljile ispitivane samonikle vrste jagodastih voćaka u poređenju sa komercijalnim sortama, dok su u pogledu hemijskog sastava ploda kod većine analiziranih parametara samonikle vrste pokazale superiornost. Rezultati sadržaja ukupnih fenola i antioksidativnog kapaciteta ploda ukazuju da su šumska jagoda (4,69 mg g-1 i 5,78 mg g-1) i samonikla kupina (3,20 mg g-1 i 4,95 mg g-1) ispoljile statistički značajno veće vrednosti u poređenju sa komercijalnim sortama. Izuzetak predstavlja samonikla malina kod koje je antioksidativni kapacitet ploda ispoljio nižu prosečnu vrednost (1,41 mg g-1) u poređenju sa sortom Willamette (3,13 mg g-1). Pozitivna linearna korelacija registrovana između sadržaja ukupnih fenola i antioksidativnog kapaciteta ploda ukazuje na činjenicu da su fenolna jedinjenja imala značajan doprinos u ispoljenoj antioksidativnoj aktivnosti

Classification and fingerprinting of different berries based on biochemical profiling and antioxidant capacity

The objective of this work was to evaluate the biochemical composition of six berry types belonging to Fragaria, Rubus, Vaccinium and Ribes genus. Fruit samples were collected in triplicate (50 fruit each) from 18 different species or cultivars of the mentioned genera, during three years (2008 to 2010). Content of individual sugars, organic acids, flavonols, and phenolic acids were determined by high performance liquid chromatography (HPLC) analysis, while total phenolics (TPC) and total antioxidant capacity (TAC), by using spectrophotometry. Principal component analysis (PCA) and hierarchical cluster analysis (CA) were performed to evaluate the differences in fruit biochemical profile. The highest contents of bioactive components were found in Ribes nigrum and in Fragaria vesca, Rubus plicatus, and Vaccinium myrtillus. PCA and CA were able to partially discriminate between berries on the basis of their biochemical composition. Individual and total sugars, myricetin, ellagic acid, TPC and TAC showed the highest impact on biochemical composition of the berry fruits. CA separated blackberry, raspberry, and blueberry as isolate groups, while classification of strawberry, black and red currant in a specific group has not occurred. There is a large variability both between and within the different types of berries. Metabolite fingerprinting of the evaluated berries showed unique biochemical profiles and specific combination of bioactive compound contents

Can glial cells save neurons in epilepsy?

Epilepsy is a neurological disorder caused by the pathological hyper-synchronization of neuronal discharges. The fundamental research of epilepsy mechanisms and the targets of drug design options for its treatment have focused on neurons. However, approximately 30% of patients suffering from epilepsy show resistance to standard anti-epileptic chemotherapeutic agents while the symptoms of the remaining 70% of patients can be alleviated but not completely removed by the current medications. Thus, new strategies for the treatment of epilepsy are in urgent demand. Over the past decades, with the increase in knowledge on the role of glia in the genesis and development of epilepsy, glial cells are receiving renewed attention. In a normal brain, glial cells maintain neuronal health and in partnership with neurons regulate virtually every aspect of brain function. In epilepsy, however, the supportive roles of glial cells are compromised, and their interaction with neurons is altered, which disrupts brain function. In this review, we will focus on the role of glia-related processes in epileptogenesis and their contribution to abnormal neuronal activity, with the major focus on the dysfunction of astroglial potassium channels, water channels, gap junctions, glutamate transporters, purinergic signaling, synaptogenesis, on the roles of microglial inflammatory cytokines, microglia-astrocyte interactions in epilepsy, and on the oligodendroglial potassium channels and myelin abnormalities in the epileptic brain. These recent findings suggest that glia should be considered as the promising next-generation targets for designing anti-epileptic drugs that may improve epilepsy and drug-resistant epilepsy.kategorija casopsisa M2

Pomološka i antioksidativna svojstva sorti crvene ribizle (Ribes rubrum L.)

Three red currant cultivars ('Heinemanns Rote Spatlese', 'Rondom' and 'Red Versailles') were assayed for pomological and antioxidant properties in the period of 2004-2006. It was found out that cv 'Rondom' was superior with regard to physical properties of bunch and fruit, whereas cv 'Heinemanns Rote Spatlese' expressed significantly lower values for these traits. However, the best chemical fruit composition was obtained by cv 'Heinemanns Rote Spatlese'. Regarding the content of some individual phenolic compounds (kaempferol, myricetin, quercetin, and ellagic acid) as well as the total phenolics, great variability was observed among the studied cultivars. Total phenolics expressed the highest value in cv 'Heinemanns Rote Spatlese' (1,70 mg GA g-1), and consequently the highest level of antioxidant capacity was recorded in this cultivar (2,13 mg ask g-1). The significant linear correlation observed between total phenolics and antioxidant capacity in cvs 'Heinemanns Rote Spatlese' (r = 0,71) and Rondom (r = 0,80) indicates that phenolic compounds had significant contribution in expressed antioxidant activities. No significant correlation was only observed in cv 'Red Versailles', which points to the fact that some another compounds might contribute to an overall antioxidant capacity.Rad prikazuje rezultate trogodišnjih ispitivanja pomoloških osobina i antioksidativnog kapaciteta ploda kod tri sorte crvene ribizle (Industrija, Rondom i Versajska crvena). Ustanovljene su značajno niže vrednosti mase grozda (4,73 g), dužine grozda (6,85 cm), broja bobica u grozdu (9,1) i mase bobice (0,60 g) kod sorte Industrija, dok u pogledu hemijskog sastava ploda, odnosno sadržaja ukupnih prostih šećera (208,7 mg g-1) i ukupnih kiselina (0,45 mg g-1), ova sorta je pokazala superiornost. Rezultati sadržaja individualnih fenolnih jedinjenja (flavonola i elaginske kiseline) ukazuju da je sorta Versajska crvena ispoljila najviše prosečne vrednosti sadržaja miricetina (1,28 μg g-1), kvercetina (3,14 μg g-1) i elaginske kiseline (6,02 μg g-1), ali istovremeno i najni- ži prosečni sadržaj ukupnih fenola (0,82 mg GA g-1). Niska korelaciona zavisnost registrovana između sadržaja ukupnih fenola i antioksidativnog kapaciteta ploda kod ove sorte, pri čemu koeficijent korelacije nije bio statistički značajan, ukazuje na činjenicu da su određena jedinjenja imala različit doprinos u ispoljenoj antioksidativnoj aktivnosti. Međutim, kod sorte Industrija se zapaža suprotna tendencija, odnosno najviše vrednosti sadržaja ukupnih fenola (1,70 mg GA g-1) i antioksidativnog kapaciteta ploda (2,13 mg ask g-1) su registrovane u plodovima ove sorte, kao i statistički značajna korelaciona zavisnost između pomenutih parametara (r = 0,71)

IRON MODULATES NOREPINEPHRINE EFFECT ON ASTROCYTES

Aims: Astrocyte position between synapses and blood vessels allows them to ful l crucial functions such as regulation of synaptic activity and potassium bu ering. Well positioned in the close vicinity of synaptic cleft astrocytes are considered to be a direct target of norepinephrine (NE). Synaptic activity and neurotransmitter actions can be in uenced by extracellular iron. Here we investigated whether iron interacts with NE and if this interaction can modulate astrocyte response to NE. Methods: To investigate the interaction between iron and norepinephrine we used spectrophotometry approach. Iron e ect on astrocyte response to NE was examined by the whole-cell patch-clamp technique. Membrane currents were recorded from cultured cortical astrocytes prepared from WT rats. Results: Using spectrophotometry we observed that iron interacts with NE which leads to the formation of a stable complex in the 1:1 stoichiometry. We also found that iron bound to NE completely blocks NE-induced increase of large-conductance calcium sensitive potassium current in astrocytes. Conclusions: Astrocyte response to NE is modi ed when this neurotransmitter forms a complex with iron. This implies that NE binding to astrocytic noradrenergic receptors may be prevented by iron. Our ndings point toward compromised astrocyte functions related to the potassium bu ering when NE action is modified by iron.kategorija M3

Redox interactions of epinephrine with iron at physiological pH

Epinephrine ((R)-4-(1-hydroxy-2-(methylamino)ethyl)-benzene-1,2-diol (Epi) is catecholamine that is released by the sympathetic nervous system and adrenal medulla. It is a physiologically important molecule that acts as a hormone, neurotransmitter, and medication with a broad range of effects 1-3 . Coordinate and redox interaction of Epi with iron affects the interactions with other molecules and its biological effects 4 . In this study, we reported details of redox interactions of Epi with Fe 2+ at pH 7.4, which correspond to the pH value of human plasma Epi and Fe 2+ form a complex that acts as a strong reducing agent. Cyclic voltammetry showed that the positions of E pa and E pc potentials were at approximately -480 and -1100 mV. This implies that Epi and Fe 2+ build a complex with unique redox properties. E1/2 was significantly lower compared to E0' for O 2 /O 2•- (-350 mV). It is important to point out this because superoxide radical anion is produced via spontaneous Fe 2+ reaction with O 2. In other words, Epi-Fe 2+ complex should be capable of reducing transition metals in (patho)physiologicaly relevant complexes that are not susceptible to reduction by O 2. Our results confirmed that Epi-Fe 2+ is capable of reducing the S-S group of glutathione disulfide. On the other hand, Epi acted in a catalyst-like fashion to promote Fe 2+ oxidation by molecular oxygen, and to a facilitated formation of the Epi–Fe 3+ complexes, at physiological pH. In addition, we examined the effects of epinepfrine and Epi/Fe3+ system on glioma cells. Epinephrine alone evokes changes in the membrane currents of glioma cells, but such effects were not observed for the complex with Fe 3+ . This implies that Epi-Fe 3+ might modulate neural activity of Epi in CNS

Supplementary data for article: Božić, B.; Korać, J.; Stanković, D. M.; Stanić, M.; Popović-Bijelić, A.; Bogdanović Pristov, J.; Spasojević, I.; Bajčetić, M. Mechanisms of Redox Interactions of Bilirubin with Copper and the Effects of Penicillamine. Chemico-Biological Interactions 2017, 278, 129–134. https://doi.org/10.1016/j.cbi.2017.10.022

Supplementary material for: [https://doi.org/10.1016/j.cbi.2017.10.022]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2570]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3105

Biliverdin-copper complex at the physiological pH

Biliverdin (BV) is a degradation product of heme catabolism, which is rapidly converted to bilirubin (BR) by BV reductase 1. Biliverdin and unconjugated BR, commonly named bile pigments, have important function in biochemical processes. The presence of copper and other biological and toxic transitional metals at significant concentrations in bile implies the possibility that metal complexes with bile pigments can be formed 2. Consequently, our interest was to study the complex of BV with copper in physiological conditions – phosphate buffer with pH 7.4. UV-Vis spectrophotometry was applied to investigate formation/degradation of complex of BV with copper ions and to check stoichiometry by titration, showing that BV interacted with Cu2+ in 1:1 stoichiometry. Mass spectroscopy analysis confirmed this – ion at m/z 643.36 was detected. The results of Raman spectroscopy of BV were in good agreement with previous reports 3. Comparing spectra of BV and BV-Cu complex, the following differences were observed: a new band at low wave number is emerged for the complex may be attributed to Cu-N bond vibration; the band which was shifted to lower energies implicates increased stability of BV in the complex; intensity changes imply a more planar structure of BV in the complex, while stronger bands in complex imply higher delocalization of π-electrons and consequently a higher stability of the BV structure. Pertinent to this, it has been proposed that complexes of BV model compounds with Cu2+ may show unusual electronic structures that exhibit a significant ligand radical character. 1H NMR spectrum of BV in phosphate buffer had a poor resolution of signals, which may originate from aggregation, but this was of little relevance here, since the addition of copper ions led to very strong effect - the complete loss of almost all lines. The loss of signals represents the result of strong paramagnetic effects that may come from an unpaired e- that is delocalized in pπ orbitalss of the ring/ligand influencing all protons in the complex. The EPR spectrum of Cu2+ (S = 1/2; I = 3/2) in phosphate buffer shows that Cu2+ is weakly coordinated in an axial symmetry with one gr line and four lines coming from hyperfine coupling along gs. The addition of BV in equimolar concentration led to the loss of Cu2+ signal. The remaining signal in the [BV]/[Cu2+] = 1 system was broad, and did not show hyperfine structure. The g-value of the isotropic signal of BV-Cu complex was significantly lower than the average g-value of Cu2+ in the phosphate buffer indicating delocalization of the spin away from the metal nucleus. Similar EPR signals have been reported previously 4. Parallel-mode EPR showed no signal. Furthermore, the spectra were run over a wide field range and no half field lines were observed, either in parallel or in perpendicular mode. These results are consistent with S = 0 for the copper center. Further, redox properties of the complex were examined. BV showed a well-defined anodic peak. The [BV]/[Cu2+] = 2 system showed two additional oxidation peaks at much lower potentials than BV. The former potential corresponds to the oxidation of Cu1+, as we have shown previously 5. There was a slight consumption of O2 in [BV]/[Cu2+] = 1 system, which may be explained by traces of ‘free’ copper. However, in the presence of an excess of copper ([BV]/[Cu2+] = 0.5), the consumption of O2 was significant. This implies that ‘free’ Cu2+ reacts with the complex and ‘shuttles’ an e- to O2. The complex was susceptible to oxidizing agents but not to reducing agents. Considering the results obtained we conclude that, at physiological pH, BV builds a complex with copper ions in 1:1 stoichiometry. The formation of complex involves the rearrangement of electronic structure which provides increased energetic stability and strong paramagnetic effects. We believe that a complex with a highly delocalized unpaired e- and the formal BV•+-Cu1+ character best suites the outlined properties, but other structures of the complex cannot be completely ruled out. The presented results may shed new light on long-standing issues of BV chemistry and catalysis in biological systems