Dragana Pavlović

Comparison of the Hypotensive and Bradycardic Activity of Ginkgo, Garlic, and Onion Extracts

The acute effect of ethanol extracts ginkgo (Ginkgo biloba L.), garlic (Allium sativum L.), and onion (Allium cepa L.) on arterial blood pressure (BP), and heart rate (HR) in anesthetized normotensive rats was examined and compared. Arterial BP was registered in the left carotid artery. The data showed that intravenous administration of the extracts produced dose-dependent and reversible hypotensive and bradycardic effects. The most effective in reducing arterial BP and HR is extract of garlic. There were statistically significant differences in bradycardic and hypotensive effects of the garlic and ginkgo extracts.

Morphological and morphometric study of protective effect of green tea in gentamicin-induced nephrotoxicity in rats.

AIMS One of the most popular beverages worldwide, green tea, was investigated for its potential protective effect in a rat model of gentamicin-induced nephrotoxicity by monitoring functional and morphological changes in kidneys. MAIN METHODS The study was conducted on four groups of rats: control group (C), treated with only gentamicin (GM), treated with only green tea (GT) and treated with both gentamicin and green tea (GT+GM). Kidney function, oxidant and antioxidant parameters of renal tissue, as well as histopathological studies were assessed. Morphometric analysis was used to quantify these histopathological changes. KEY FINDINGS Gentamicin caused significant elevations in serum creatinine and urea and oxidative stress parameter (AOPP), while antioxidative enzyme catalase was significantly decreased. Histological sections of kidneys in GM group revealed necrosis of proximal tubules, vacuolation of cytoplasm and massive mononuclear inflammatory infiltrates in interstitium. Coadministration of green tea with gentamicin histologically showed renoprotective effect. Histological results were confirmed and quantified by morphometric analysis. Also in this group we measured ameliorated parameters of renal functions and antioxidative defense. SIGNIFICANCE Regenerative potential of green tea after renal injury induced by gentamicin could be explained through the decrease of oxidative stress and lipid peroxidation. Green tea is a natural antioxidant, with many health promoting effects, widely available and in accordance to that affordable. Because of the established habits, people largely consume it as a beverage. It could be beneficial in the reduction of oxidative stress and changes caused by it primarily in renal tubules and interstitium.

Comparative Study of Spasmolytic Properties, Antioxidant Activity and Phenolic Content of Arbutus unedo from Montenegro and Greece

Arbutus unedo leaf is used traditionally for gastrointestinal complaints. Ethanol extracts from Arbutus unedo collected in both Montenegro (AuM) and Greece (AuG) were found to decrease the ileal basal tonus, with AuG producing a significantly higher (p < 0.05) reduction in contractile response to acetylcholine. AuM and AuG relaxed 80 mm K+ induced contractions and shifted the Ca++ concentration–response curves to the right, similar to that caused by verapamil, suggesting that the spasmolytic effect was induced through calcium channel inhibition. The antioxidant activity of AuM and AuG and the phenolic content of the extracts and dry plant material were studied, and both extracts were found to possess considerable antioxidant properties. AuG showed a stronger in vitro antioxidative activity in the DPPH assay and in the TBA test. Polyphenol, tannin and flavonoid levels were higher in AuG, supporting the more potent spasmolytic and antioxidative effects, whereas the arbutin content was higher in dry plant material collected in Montenegro. Copyright

Antimicrobial activity of selected plant species of Genera arbutus l., Bruckenthalia rchb., Calluna salisb. and Erica l. (Ericaceae)

SUMMARY Uvae ursi folium (Arctostaphylos uva ursi, Ericaceae) is the best known and most widely used herbal urinary antiseptic. In traditional medicine, other Ericaceae species are also used for the treatment of urinary tract infections. The present study investigates antimicrobial activity of five species of Ericaceae family native to the Balkan Peninsula: Arbutus unedo, Bruckenthalia spiculifolia, Calluna vulgaris, Erica arborea and Erica carnea. Ethanolic extracts were tested against 10 different gram-positive and gram-negative bacteria by the disc diffusion technique, where standard tetracycline, streptomycin and penicillin discs and discs containing crystal violet (1 mg/ml) and solvent (70.0% v/v ethanol) were used as controls. The most prominent antibacterial effect was achieved on Staphylococcus aureus with extracts of Calluna vulgaris and Erica carnea. Tested samples showed no activity against the gram-negative strains Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Inhibitory effects on the growth of gram-positive bacteria were more potent. The exception is Arbutus unedo ethanol extract which exhibited certain activity against a laboratory strain of wild Escherichia coli. Antimicrobial activity of the ethanolic extracts against 10 tested strains of bacteria in disc diffusion assay was generally weak, even for sample in which HPLC determination confirmed the presence of arbutin (secondary metabolite responsible for most of the antibacterial activity of Uvaeursi folium). Sažetak Najpoznatiji i najviše korišćeni biljni uroantiseptik je list uve, Uvaeursi folium (Arctostaphylos uva ursi, Ericaceae). U tradicionalnoj medicini često se i druge vrste familije Ericaceae spominju u lečenju urinarnih infekcija. Provera antimikrobne aktivnosti izvršena je za sledeće biljne vrste ove familije koje samostalno rastu u flori Balkanskog poluostrva: Arbutus unedo, Bruckentalia spiculifolia, Calluna vulgaris, Erica arborea i Erica carnea. Antimikrobna aktivnost etanolnih ekstrakata listova ispitivana je diskdifuzionom metodom, korišćenjem 10 sojeva gram pozitivnih i gram negativnih bakterija, pri čemu su kao kontrole korišćeni standardni diskovi tetraciklina, streptomicina i penicilina, kao i diskovi sa rastvorom kristalvioleta (1 mg/ml) i rastvarača (70.0% v/v etanol). Pseudomonas aeruginosa, Escherichia coli i Klebsiella pneumoniae nisu osetljive ni na jedan od ispitivanih ekstrakata. Kao najbolji rezultati mogu se izdvojiti aktivnosti ekstrakta Calluna vulgaris i Erica carnea na bakterijski soj Staphylococcus aureus. Testirani uzorci uglavnom ispoljavaju antimikrobnu aktivnost prema gram pozitivnim sojevima. Izuzetak je etanolni ekstrakt vrste Arbutus unedo, koji ispoljava određenu antimikrobnu aktivnost prema laboratorijskom soju Escherichia coli. Antimikrobna aktivnost etanolnih ekstrakata prema 10 testiranih bakterijskih sojeva u diskdifuzionoj metodi je veoma slaba, čak i za uzorak za koji je HPLC analizom utvrđeno prisustvo arbutina (sekundarni metabolit odgovoran za uroantiseptično dejstvo lista uve).

Bilberry: Chemical Profiling, in Vitro and in Vivo Antioxidant Activity and Nephroprotective Effect against Gentamicin Toxicity in Rats

We assessed possible protective effect of bilberry diet in rat model of nephrotoxicity. In vivo and in vitro antioxidant activity and chemical profiling of this functional food was performed. With aid of HPLC‐DAD and spectrophotometric method, 15 individual anthocyanins were quantified alongside total tannin, phenylpropanoid, and anthocyanin content. The study was conducted on four groups of rats: control, treated with only gentamicin, treated with only bilberry, and treated with both gentamicin and bilberry. Kidney function was evaluated by tracking urea and creatinine. Morphology of renal tissue and its changes were recorded pathohistologically and quantified morphometrically. Bilberry (100 mg/kg daily) showed strong nephroprotective effect against gentamicin toxicity in rats (as shown through MDA, AOPP, and catalase levels). In conclusion, the demonstrated protective activity of bilberry extract matched well with the assessed in vivo and in vitro antioxidant activity as well as with its polyphenolic content, particularly with high anthocyanin levels. Copyright

Student Preferences With Regards to the Use of Internet Content: Gender Differences

Abstract Youth population is the one most receptive to the appearance and use of new technologies, whichrenders the focus of researchers on the relationship between the young and the Internet quite justified. Considerableattention is drawn to particular variables such as age, education, gender and socioeconomic status, which areconsidered the most significant predictors of online behavior. The paper presents the results of a research based ona quantitative approach the aim of which was to examine Internet content preferences depending on the gender ofstudents in the Balkans, and the results of the research point to the presence of gender differences. In comparisonto female students, male students mostly prefer educational and entertainment content on the Internet. On theother hand, the obtained data shows that online video gaming and ecommerce services are dominated by femalerespondents.

Effects of Extracts of Ginkgo, Onion, and Celery on the Contractility of Isolated Rat Atria

The acute negative inotropic and chronotropic effects of the commercial extract of ginkgo leaf (Gingium®) and ethanolic extracts of onion bulbs and celery root on spontaneous and noradrenalin-stimulated contractions of the Wistar rat atria were investigated. All analyzed extracts exerted negative inotropic effects on the isolated rat atria. Among the tested extracts, the extract of ginkgo showed the strongest negative inotropic effects on rat atria, either in spontaneous or noradrenalin-induced contractions, being more potent than the onion and celery extracts, respectively.

Beneficial Effects of Green Tea Extract in Gentamicin-Induced Acute Renal Failure in Rats / Povoljni efekti ekstrakta zelenog čaja na akutnu bubrežnu insuficijenciju uzrokovanu gentamicinom kod pacova

Summary The aim of this study was to investigate whether green tea extract has beneficial effect on gentamicin-induced acute renal failure. The investigation was conducted on thirty-two Wistar rats divided into four groups of 8 animals each. Control (C) group received normal saline. GT group received green tea extract orally, 300mg/kg. GM group received gentamicin intraperitoneally, 100mg/kg and GT+GM group received both gentamicin and green tea extract. Histological sections of kidney in GM group revealed necrosis of proximal tubules, vacuolization of cytoplasm and massive mononuclear inflammatory infiltrates in interstitium. Coadministration of green tea with gentamicin had renoprotective effect and showed only mild infiltrations, normal glomeruli and alleviated tubular degeneration. Analysis of biochemical parameters showed significantly higher urea and creatinine serum concentrations in GM group in comparison with C group and GT+GM group (p<0.001). Plasma lipid peroxidation biomarker MDA was significantly higher in GM group than those in C group (p<0.001), whereas the values for GT+GM group were significantly lower than MDA recorded for GM group (p<0.001). Beneficial effects of green tea on gentamicin-induced nephrotoxicity is explained through decrease of oxidative stress and lipid peroxidation.Our results indicate that green tea administration has nephroprotective effect on oxidative stress and acute renal failure caused by gentamicin. Sažetak Cilj našeg istraživanja bio je da ispitamo efekat zelenog čaja na akutnu bubrežnu insuficijenciju uzrokovanu gentamicinom. Istraživanje smo sproveli na trideset dva pacova Wistar soja koje smo podelili u četiri grupe od po 8 životinja. Kontrolna (C) grupa primala je fiziološki rastvor. GT grupa je primala oralno ekstrakt zelenog čaja u dozi od 300 mg/kg. GM grupa primala je gentamicin intraperitonealno u dozi od 100 mg/kg, a GT+GM grupa primala je zajedno gentamicin i ekstrakt zelenog čaja. Histološki preparati bubrega pacova GM grupe pokazali su nekrozu proksimalnih tubula, vakuolizaciju citoplazme i masivni mononuklearni zapaljenski infiltrat u intersticijumu. Istovremena primena zelenog čaja sa gentamicinom imala je renoprotektivni efekat i pokazala samo blage infiltrate, normalne glomerule i smanjenu degeneraciju tubula. Analiza biohemijskih parametara pokazala je statistički značajno povećanje koncentracije uree i kreatinina u GM grupi, u poređenju sa C grupom i GT+GM grupom (p<0,001). Biomarker lipidne peroksidacije u plazmi MDA bio je značajno viši u GM grupi u odnosu na C grupu (p<0,001), dok su njegove vrednosti u GT+GM grupi bile značajno niže u poređenju sa GM grupom (p<0,001). Korisni efekti zelenog čaja na gentamicinom uzrokovanu nefrotoksičnost mogu se objasniti smanjenjem oksidativnog stresa i lipidne peroksidacije. Naši rezultati ukazuju da primena zelenog čaja ima protektivni efekat na oksidativni stres i akutnu bubrežnu insuficijenciju uzrokovanu gentamicinom.