Dragana Dekanski - Academia.edu (original) (raw)
Papers by Dragana Dekanski
Mediterranean Journal of Nutrition and Metabolism, 2009
gastric lesions induced. Furthermore, OLE was effective in the prevention of an increase in gastr... more gastric lesions induced. Furthermore, OLE was effective in the prevention of an increase in gastric lipid peroxidation and in the prevention of a decrease in antioxidative enzyme activity. The results obtained indicate that OLE has gastroprotective activity against ethanol-induced gastric lesions in rats, possibly related to its antioxidative properties.
British Journal of Nutrition, 2010
The health-promoting effects of various constituents of the olive tree (Olea europaea) are mainly... more The health-promoting effects of various constituents of the olive tree (Olea europaea) are mainly associated with hypoglycaemic and insulinsensitising activities and have been widely demonstrated in the metabolic syndrome and type 2 diabetes. However, their biological activity in autoimmune type 1 diabetes (T1D) is poorly characterised. Therefore, the influence of O. europaea-derived components present in dry olive leaf extract (DOLE) was examined in two established preclinical models of human T1D, which differ in some aspects of diabetogenesis: multiple low-dose streptozotocin-induced diabetes in susceptible C57BL/6 and CBA/H mouse strains; cyclophosphamide-accelerated diabetes in non-obese diabetic mice. In both T1D models, in vivo administration of DOLE significantly reduced clinical signs of diabetes (hyperglycaemia and body weight loss) and led to complete suppression of histopathological changes in pancreatic islets. In line with these, insulin expression and release were restored in DOLE-treated mice. Interestingly, inducible NO synthase expression and NO production were significantly elevated in peripheral tissues but were down-regulated within the local environment of the endocrine pancreas. This interference was reflected in NO-mediated suppression of T lymphocyte proliferation and lower production of the proinflammatory cytokines interferon-g, IL-17 and TNF-a in the spleen, with subsequent blockade of b-cell destruction. The results suggest that DOLE interferes with development of autoimmune diabetes by downregulating production of proinflammatory and cytotoxic mediators. Therefore, the potential use of a DOLE-enriched diet for prophylaxis/treatment of human T1D, and possibly other autoimmune diseases, is worthy of further investigation.
PLoS ONE, 2011
Background and Aim: Free radicals are implicated in the aetiology of gastrointestinal disorders s... more Background and Aim: Free radicals are implicated in the aetiology of gastrointestinal disorders such as gastric ulcer, colorectal cancer and inflammatory bowel disease. Strawberries are common and important fruit due to their high content of essential nutrient and beneficial phytochemicals which seem to have relevant biological activity on human health. In the present study we investigated the antioxidant and protective effects of three strawberry extracts against ethanol-induced gastric mucosa damage in an experimental in vivo model and to test whether strawberry extracts affect antioxidant enzyme activities in gastric mucosa.
Phytomedicine, 2011
The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral i... more The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral ischemia/reperfusion brain injury are well known. Mediterranean diet, rich in olive products, is associated with lower incidence of cardiovascular disease, cancer, inflammation and stroke. In this study, the possible neuroprotective effect of standardized dry olive leaf extract (OLE) is investigated for the first time. Transient global cerebral ischemia in Mongolian gerbils was used to investigate the OLE effects on different parameters of oxidative stress and neuronal damage in hippocampus. The biochemical measurements took place at different time points (80 min, 2, 4 and 24 h) after reperfusion. The effects of applied OLE were compared with effects of quercetin, a known neuroprotective plant flavonoid. Pretreatment with OLE (100 mg/kg, per os) significantly inhibited production of superoxide and nitric oxide, decreased lipid peroxidation, and increased superoxide dismutase activity in all time points examined. Furthermore, OLE offered histological improvement as seen by decreasing neuronal damage in CA1 region of hippocampus. The effects of applied OLE were significantly higher than effects of quercetin (100 mg/kg, per os). Our results indicate that OLE exerts a potent neuroprotective activity against neuronal damage in hippocampus after transient global cerebral ischemia, which could be attributed to its antioxidative properties.
Molecular and Cellular Biochemistry, 2010
The aim of this study was to investigate the dynamics of lipid peroxidation and the possible corr... more The aim of this study was to investigate the dynamics of lipid peroxidation and the possible correlation between lipid peroxidation in different brain regions and behavioral manifestations in lindane-induced seizures in rats. Male Wistar rats were divided into the following groups: 1. control, saline-treated group; 2. dimethylsulfoxide (DMSO)-treated group; 3. lindane-treated group (8 mg/kg), intraperitoneally. Animals were sacrificed 0.5 or 4 h after treatment and the malondialdehyde level and superoxide dismutase (SOD) activity were determined in various brain regions spectrophotometrically. Behavioral changes were classified according to the descriptive scale (0-no response, 1-head nodding, lower jaw twitching; 2-myoclonic body jerks, bilateral forelimb clonus with full rearing; 3-progression to generalized clonic convulsions followed by tonic extension of fore-and hind limbs and tail; 4-status epilepticus). A significant rise in the malondialdehyde level was detected in the cerebral cortex, hippocampus, and thalamus of lindane-treated animals 0.5 and 4 h after administration (P \ 0.05). SOD activity (total and mitochondrial) was significantly decreased in the hippocampus and the cortex of lindane-treated animals at both time points (P \ 0.05). An initial fall in SOD activity was detected in the thalamus 4 h after lindane administration (P \ 0.05). A positive correlation between seizure severity and the malondialdehyde level was found in the hippocampus at both time points (P \ 0.01). These results suggest that lipid peroxidation may contribute to the neurotoxic effects of lindane in early acute lindane intoxication and that behavioral manifestations correlate with lipid peroxidation in the hippocampus of lindane-treated rats.
Journal of the Serbian Chemical Society, 2009
Some medicinal features of olive leaf have been known for centuries. It has been traditionally us... more Some medicinal features of olive leaf have been known for centuries. It has been traditionally used as an antimicrobial and to prevent and treat diabetes mellitus and heart disease. Whether olive leaf, a natural antioxidant, influences the gastric defense mechanism and exhibits gastroprotection against experimentally-induced gastric lesions remains unknown. In this study, the content of total phenols, total flavonoids and tannins in olive leaf extract (OLE) were determined. Seven phenolic compounds were identified and quantified (oleuropein, caffeic acid, luteolin, luteolin-7-O-glucoside, apigenin-7-O-glucoside, quercetin, and chryseriol). Furthermore, the protective activity of the OLE in gastric mucosal injury induced by a corrosive concentration of ethanol was investigated. In relation to the control group, pretreatment with OLE (40, 80 and 120 mg kg -1 ) significantly (p < 0.001) attenuated the gastric lesions induced by absolute ethanol. The protective effect of the OLE was similar to that obtained with a reference drug, ranitidine. The results obtained indicate that OLE possesses significant gastroprotective activity, and that the presence of compounds with antioxidative properties would probably explain this effect.
Journal of the Serbian Chemical Society, 2013
Novel metal-based compounds with therapeutic potential have become the subject of intense investi... more Novel metal-based compounds with therapeutic potential have become the subject of intense investigations in inorganic chemistry and biomedical science. Recently, strong dose-dependent cytotoxic activities of selenosemicarbazone metal complexes against several human cancer cell lines were demonstrated. The aim of the present study was to investigate in vitro antioxidative potential of Ni(II), Cd(II) and Zn(II) selenosemicarbazone complexes. All three investigated complexes exhibited high 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS •+ ) scavenging capacity, comparable with ascorbic acid. In an acute toxicity study, administration of the compounds was performed orally to mice at single doses. The mice were observed for clinical signs, body weight effects and mortality for 14 days, after which they were sacrificed for gross organ necropsy. The body weight did not vary after administration, and the autoptic analysis failed to show appreciable macroscopic alterations of internal organs. Generally, the compounds exhibited low toxic effects as required for further in vivo therapeutic studies.
Canadian Journal of Physiology and Pharmacology, 2004
The purpose of this study was to investigate the characteristics of transport of endogenous nucle... more The purpose of this study was to investigate the characteristics of transport of endogenous nucleosides into cardiac tissue from coronary circulation. The study was performed on the isolated perfused guinea pig heart, using the rapid paired tracers single-pass technique. The maximal cellular uptake (t/max) ^fd total cellular uptake (t/,(,() of adenosine, deoxyadenosine, thymidine, uridine, and cytidine were determined. The cellular uptake of adenosine was significantly higher than the cellular uptake of other studied nucleosides. To elucidate the mechanisms of nucleoside transport, competition studies were performed and the influence of 5-(p-nitrobenzyl)-6-thioinosine (NBTI) and sodium ion absence on U^^^ and f/,,,, was investigated. Self-and cross-inhibition studies indicated the saturable mechanism of nucleosides transport into cardiac tissue and the involvement of different transport mechanisms for purine and pyrimidine nucleosides. The study also showed that both equilibrative-sensitive (e,s) and sodium-dependent transport were responsible for adenosine and thymidine cellular uptake.
Acta Physiologica Hungarica, 2006
ABSTRACT The aim of this study was to determine the mechanism of transport of 3-deazaguanine in t... more ABSTRACT The aim of this study was to determine the mechanism of transport of 3-deazaguanine in the rat heart. We used single-pass, paired-tracer dilution method on isolated and retrogradely perfused rat hearts. The maximal cellular uptake (Umax) and total cellular uptake (Utot) of 3-deazaguanine were determined under control conditions and under influence of possible modifiers. Both Umax and Utot were significantly reduced in the presence of unlabeled 3-deazaguanine (from 19.57 +/- 2.02% to 8.14 +/- 1.19% and from 16.49 +/- 3.65% to 4.70 +/- 1.96%, n=6, respectively). The presence of pyrimidine nucleoside thymidine caused the reduction of both Umax and Utot (from 20.03 +/- 3.76% to 13.58 +/- 3.16% and from 16.43 +/- 3.58% to 11.94 +/- 3.13%, n=6, respectively). Also, we tested the effect of the absence of sodium ions in perfusion solution (both Umax and Utot, significantly reduced from 17.95 +/- 2.73% to 16.67 +/- 2.16% and from 16.68 +/- 2.97% to 14.81 +/- 3.04%, n=6, respectively) and the effect of dinitrophenol (both Umax and Utot significantly reduced from 19.09 +/- 3.68% to 10.58 +/- 3.14% and from 16.86 +/- 3.84% to 7.10 +/- 3.11%, n=6, respectively). The results of self- and cross-inhibition studies show that the transport of 3-deazaguanine is saturable, energy- and sodium-dependent and that 3-deazaguanine uses endogenous transport systems for thymidine and adenosine for its own transport.
Clinical Nutrition, 2009
Background & aims: Experimental autoimmune encephalomyelitis (EAE) is an animal model of CNS infl... more Background & aims: Experimental autoimmune encephalomyelitis (EAE) is an animal model of CNS inflammatory and demyelinating disease multiple sclerosis. Mediterranean diet, rich in olive products is associated with lower incidence of multiple sclerosis in South European population. Therefore, the influence of dry olive leaf extract (DOLE) on EAE course was investigated.
Mediterranean Journal of Nutrition and Metabolism, 2009
gastric lesions induced. Furthermore, OLE was effective in the prevention of an increase in gastr... more gastric lesions induced. Furthermore, OLE was effective in the prevention of an increase in gastric lipid peroxidation and in the prevention of a decrease in antioxidative enzyme activity. The results obtained indicate that OLE has gastroprotective activity against ethanol-induced gastric lesions in rats, possibly related to its antioxidative properties.
British Journal of Nutrition, 2010
The health-promoting effects of various constituents of the olive tree (Olea europaea) are mainly... more The health-promoting effects of various constituents of the olive tree (Olea europaea) are mainly associated with hypoglycaemic and insulinsensitising activities and have been widely demonstrated in the metabolic syndrome and type 2 diabetes. However, their biological activity in autoimmune type 1 diabetes (T1D) is poorly characterised. Therefore, the influence of O. europaea-derived components present in dry olive leaf extract (DOLE) was examined in two established preclinical models of human T1D, which differ in some aspects of diabetogenesis: multiple low-dose streptozotocin-induced diabetes in susceptible C57BL/6 and CBA/H mouse strains; cyclophosphamide-accelerated diabetes in non-obese diabetic mice. In both T1D models, in vivo administration of DOLE significantly reduced clinical signs of diabetes (hyperglycaemia and body weight loss) and led to complete suppression of histopathological changes in pancreatic islets. In line with these, insulin expression and release were restored in DOLE-treated mice. Interestingly, inducible NO synthase expression and NO production were significantly elevated in peripheral tissues but were down-regulated within the local environment of the endocrine pancreas. This interference was reflected in NO-mediated suppression of T lymphocyte proliferation and lower production of the proinflammatory cytokines interferon-g, IL-17 and TNF-a in the spleen, with subsequent blockade of b-cell destruction. The results suggest that DOLE interferes with development of autoimmune diabetes by downregulating production of proinflammatory and cytotoxic mediators. Therefore, the potential use of a DOLE-enriched diet for prophylaxis/treatment of human T1D, and possibly other autoimmune diseases, is worthy of further investigation.
PLoS ONE, 2011
Background and Aim: Free radicals are implicated in the aetiology of gastrointestinal disorders s... more Background and Aim: Free radicals are implicated in the aetiology of gastrointestinal disorders such as gastric ulcer, colorectal cancer and inflammatory bowel disease. Strawberries are common and important fruit due to their high content of essential nutrient and beneficial phytochemicals which seem to have relevant biological activity on human health. In the present study we investigated the antioxidant and protective effects of three strawberry extracts against ethanol-induced gastric mucosa damage in an experimental in vivo model and to test whether strawberry extracts affect antioxidant enzyme activities in gastric mucosa.
Phytomedicine, 2011
The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral i... more The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral ischemia/reperfusion brain injury are well known. Mediterranean diet, rich in olive products, is associated with lower incidence of cardiovascular disease, cancer, inflammation and stroke. In this study, the possible neuroprotective effect of standardized dry olive leaf extract (OLE) is investigated for the first time. Transient global cerebral ischemia in Mongolian gerbils was used to investigate the OLE effects on different parameters of oxidative stress and neuronal damage in hippocampus. The biochemical measurements took place at different time points (80 min, 2, 4 and 24 h) after reperfusion. The effects of applied OLE were compared with effects of quercetin, a known neuroprotective plant flavonoid. Pretreatment with OLE (100 mg/kg, per os) significantly inhibited production of superoxide and nitric oxide, decreased lipid peroxidation, and increased superoxide dismutase activity in all time points examined. Furthermore, OLE offered histological improvement as seen by decreasing neuronal damage in CA1 region of hippocampus. The effects of applied OLE were significantly higher than effects of quercetin (100 mg/kg, per os). Our results indicate that OLE exerts a potent neuroprotective activity against neuronal damage in hippocampus after transient global cerebral ischemia, which could be attributed to its antioxidative properties.
Molecular and Cellular Biochemistry, 2010
The aim of this study was to investigate the dynamics of lipid peroxidation and the possible corr... more The aim of this study was to investigate the dynamics of lipid peroxidation and the possible correlation between lipid peroxidation in different brain regions and behavioral manifestations in lindane-induced seizures in rats. Male Wistar rats were divided into the following groups: 1. control, saline-treated group; 2. dimethylsulfoxide (DMSO)-treated group; 3. lindane-treated group (8 mg/kg), intraperitoneally. Animals were sacrificed 0.5 or 4 h after treatment and the malondialdehyde level and superoxide dismutase (SOD) activity were determined in various brain regions spectrophotometrically. Behavioral changes were classified according to the descriptive scale (0-no response, 1-head nodding, lower jaw twitching; 2-myoclonic body jerks, bilateral forelimb clonus with full rearing; 3-progression to generalized clonic convulsions followed by tonic extension of fore-and hind limbs and tail; 4-status epilepticus). A significant rise in the malondialdehyde level was detected in the cerebral cortex, hippocampus, and thalamus of lindane-treated animals 0.5 and 4 h after administration (P \ 0.05). SOD activity (total and mitochondrial) was significantly decreased in the hippocampus and the cortex of lindane-treated animals at both time points (P \ 0.05). An initial fall in SOD activity was detected in the thalamus 4 h after lindane administration (P \ 0.05). A positive correlation between seizure severity and the malondialdehyde level was found in the hippocampus at both time points (P \ 0.01). These results suggest that lipid peroxidation may contribute to the neurotoxic effects of lindane in early acute lindane intoxication and that behavioral manifestations correlate with lipid peroxidation in the hippocampus of lindane-treated rats.
Journal of the Serbian Chemical Society, 2009
Some medicinal features of olive leaf have been known for centuries. It has been traditionally us... more Some medicinal features of olive leaf have been known for centuries. It has been traditionally used as an antimicrobial and to prevent and treat diabetes mellitus and heart disease. Whether olive leaf, a natural antioxidant, influences the gastric defense mechanism and exhibits gastroprotection against experimentally-induced gastric lesions remains unknown. In this study, the content of total phenols, total flavonoids and tannins in olive leaf extract (OLE) were determined. Seven phenolic compounds were identified and quantified (oleuropein, caffeic acid, luteolin, luteolin-7-O-glucoside, apigenin-7-O-glucoside, quercetin, and chryseriol). Furthermore, the protective activity of the OLE in gastric mucosal injury induced by a corrosive concentration of ethanol was investigated. In relation to the control group, pretreatment with OLE (40, 80 and 120 mg kg -1 ) significantly (p < 0.001) attenuated the gastric lesions induced by absolute ethanol. The protective effect of the OLE was similar to that obtained with a reference drug, ranitidine. The results obtained indicate that OLE possesses significant gastroprotective activity, and that the presence of compounds with antioxidative properties would probably explain this effect.
Journal of the Serbian Chemical Society, 2013
Novel metal-based compounds with therapeutic potential have become the subject of intense investi... more Novel metal-based compounds with therapeutic potential have become the subject of intense investigations in inorganic chemistry and biomedical science. Recently, strong dose-dependent cytotoxic activities of selenosemicarbazone metal complexes against several human cancer cell lines were demonstrated. The aim of the present study was to investigate in vitro antioxidative potential of Ni(II), Cd(II) and Zn(II) selenosemicarbazone complexes. All three investigated complexes exhibited high 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS •+ ) scavenging capacity, comparable with ascorbic acid. In an acute toxicity study, administration of the compounds was performed orally to mice at single doses. The mice were observed for clinical signs, body weight effects and mortality for 14 days, after which they were sacrificed for gross organ necropsy. The body weight did not vary after administration, and the autoptic analysis failed to show appreciable macroscopic alterations of internal organs. Generally, the compounds exhibited low toxic effects as required for further in vivo therapeutic studies.
Canadian Journal of Physiology and Pharmacology, 2004
The purpose of this study was to investigate the characteristics of transport of endogenous nucle... more The purpose of this study was to investigate the characteristics of transport of endogenous nucleosides into cardiac tissue from coronary circulation. The study was performed on the isolated perfused guinea pig heart, using the rapid paired tracers single-pass technique. The maximal cellular uptake (t/max) ^fd total cellular uptake (t/,(,() of adenosine, deoxyadenosine, thymidine, uridine, and cytidine were determined. The cellular uptake of adenosine was significantly higher than the cellular uptake of other studied nucleosides. To elucidate the mechanisms of nucleoside transport, competition studies were performed and the influence of 5-(p-nitrobenzyl)-6-thioinosine (NBTI) and sodium ion absence on U^^^ and f/,,,, was investigated. Self-and cross-inhibition studies indicated the saturable mechanism of nucleosides transport into cardiac tissue and the involvement of different transport mechanisms for purine and pyrimidine nucleosides. The study also showed that both equilibrative-sensitive (e,s) and sodium-dependent transport were responsible for adenosine and thymidine cellular uptake.
Acta Physiologica Hungarica, 2006
ABSTRACT The aim of this study was to determine the mechanism of transport of 3-deazaguanine in t... more ABSTRACT The aim of this study was to determine the mechanism of transport of 3-deazaguanine in the rat heart. We used single-pass, paired-tracer dilution method on isolated and retrogradely perfused rat hearts. The maximal cellular uptake (Umax) and total cellular uptake (Utot) of 3-deazaguanine were determined under control conditions and under influence of possible modifiers. Both Umax and Utot were significantly reduced in the presence of unlabeled 3-deazaguanine (from 19.57 +/- 2.02% to 8.14 +/- 1.19% and from 16.49 +/- 3.65% to 4.70 +/- 1.96%, n=6, respectively). The presence of pyrimidine nucleoside thymidine caused the reduction of both Umax and Utot (from 20.03 +/- 3.76% to 13.58 +/- 3.16% and from 16.43 +/- 3.58% to 11.94 +/- 3.13%, n=6, respectively). Also, we tested the effect of the absence of sodium ions in perfusion solution (both Umax and Utot, significantly reduced from 17.95 +/- 2.73% to 16.67 +/- 2.16% and from 16.68 +/- 2.97% to 14.81 +/- 3.04%, n=6, respectively) and the effect of dinitrophenol (both Umax and Utot significantly reduced from 19.09 +/- 3.68% to 10.58 +/- 3.14% and from 16.86 +/- 3.84% to 7.10 +/- 3.11%, n=6, respectively). The results of self- and cross-inhibition studies show that the transport of 3-deazaguanine is saturable, energy- and sodium-dependent and that 3-deazaguanine uses endogenous transport systems for thymidine and adenosine for its own transport.
Clinical Nutrition, 2009
Background & aims: Experimental autoimmune encephalomyelitis (EAE) is an animal model of CNS infl... more Background & aims: Experimental autoimmune encephalomyelitis (EAE) is an animal model of CNS inflammatory and demyelinating disease multiple sclerosis. Mediterranean diet, rich in olive products is associated with lower incidence of multiple sclerosis in South European population. Therefore, the influence of dry olive leaf extract (DOLE) on EAE course was investigated.