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In the previous study fifteen jatrophane diterpenes were isolated from the Euphorbia nicaeensis latex. Fourteen of them have been shown to be potent P-glycoprotein (P-gp) inhibitor in two MDR cancer cells (NCI-H460/R and DLD1-TxR). The aim of this study was to determine whether and which jatrophane diterpenes can be isolated from the root of the plant, and then to examine their inhibition power on P-glycoprotein of selected cancer cell lines (NCI- -H460, DLD1, U87, NCI-H460/R, DLD1-TxR and U87-TxR). Two previously undescribed jatrophane diterpenes were isolated from the root of E. nicaeensis collected in Deliblato Sand (Serbia). The structures of the isolated compounds were determined using 1D and 2D NMR, as well as HRESIMS data. The results obtained by MTT assay showed different antitumor potential of these two jatrophanes. Compound 1 inhibited cell growth of non-small cell lung carcinoma cell lines NCI-H460 and NCI-H460/R, as well as glioblastoma cell lines U87 and U87-TxR, while jatrophane 2 was almost completely inactive in the suppression of cancer cell growth in a given range of concentrations. The obtained results also showed that the isolated compounds have an inhibitory effect on P-glycoprotein, as well as that their inhibitory potential is similar.

The health promoting effects of hot water extracts obtained from fruiting bodies of the commercially cultivated mushroom Agaricus bisporus (AbHW) and the wild-growing mushroom Ganoderma resinaceum (GrHW) originating from northern Serbia are presented in this research. These abilities were compared in vitro by the prevention of lipid peroxidation (LPx) in a linoleic acid model system, inhibition of the angiotension converting I enzyme (ACE) that could help in the maintenance of a normal blood pressure level and strengthening the ability of the central cholinergic neuron by inhibiting the activity of acetylcholinesterase (AChE). Cytotoxic activities were observed towards selected human malignant (HeLa and K562) cell lines and normal- -human peripheral blood mononuclear cells (PBMC). GrHW contains higher phenolics (5.9 g (100 g)-1), inhibition of LPx (EC50 = 1.07 mg mL-1), ACE (IC50 = 0.54 mg mL-1) and AChE (IC50 = 0.37 mg mL-1), and exhibited a significant selectivity in the antitumour action against HeLa (IC50 = 0.14 mg mL-1) and K562 (IC50 = 0.11 mg mL-1) cells. AbHW contained higher total protein (6.4 g (100 g)-1), carbohydrate (75.4 g (100 g)-1) and β-glucan (55.1 g (100 g)-1) contents and induced significant proliferation of healthy PBMC from 152–116 % in the concentration range of 0.047–0.187 mg mL-1. The difference in the biological activity of the extracts provides guidance on their use as functional food. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 46001, Grant no. III 46010 and Grant no. III 43004]

Pumpkin fruit is used in a diet since ancient times especially in rural communities. The major contributory factors of nutritional and medicinal value of pumpkins are carotenoids, polysaccharides, vitamins, minerals, and phenolic compounds. Due to a very large fruit that it is not easy to consume a whole as well as short shelf-life of fresh-cut pumpkin, different ways of conserving and processing are performed. In our study, total carotenoids, total phenolics and individual phenolics in fresh pumpkin and pumpkin traditional products such as sweet in wine, jam and juice, which are typical for northern parts of Serbia, were studied. Total carotenoids ranged from 27.6 μg/g of pumpkin sweet in wine to 86.3 μg/g of fresh fruit, while the amount of total phenolics varied between 93.0 μg GAE/g of pumpkin juice and 905.9 μg GAE/g of fresh fruit. Eight phenolic compounds were identified in the investigated samples and among them phenolic acids dominated. Among flavonoids, flavanon glycoside hesperidin was detected. [Projekat Ministarstva nauke Republike Srbije, br. 46013]

This study describes the investigation of degradation products of donepezil (DP) using stability indicating RP-HPLC method for determination of donepezil, which is a centrally acting reversible acetylcholinesterase inhibitor. In order to investigate the stability of drug and formed degradation products, a forced degradation study of drug sample and finished product under different forced degradation conditions has been conducted. Donepezil hydrochloride and donepezil tablets were subjected to stress degradation conditions recommended by International Conference on Harmonization (ICH). Donepezil hydrochloride solutions were subjected to acid and alkali hydrolysis, chemical oxidation and thermal degradation. Significant degradation was observed under alkali hydrolysis and oxidative degradation conditions. Additional degradation products were observed under the conditions of oxidative degradation. The degradation products observed during forced degradation studies were monitored using the high performance liquid chromatography (HPLC) method developed. The parent method was modified in order to obtain LC-MS compatible method which was used to identify the degradation products from forced degradation samples using high resolution mass spectrometry. The mass spectrum provided the precise mass from which derived molecular formula of drug substance and degradation products formed and proved the specificity of the method unambiguously. [Projekat Ministarstva nauke Republike Srbije, br. 172013]

An isocratic, reversed-phase liquid chromatographic method was applied for the investigation of the degradation products of amlodipine besylate under the stressed conditions in solution. Amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and photodegradation as well as to the electrochemical degradation by cyclic voltammetry in 0.05 mol/L NaHCO3 on gold electrode. The total degradation of amlodipine besylate was achieved in 5 mol/L NaOH at 80°C for 6 h and the compound with molecular formula C15H16NOCl was identified as a main degradation product. Under acidic (5 mol/L HCl at 80°C for 6 h) stress conditions 75.2% of amlodipine besylate degradation was recorded. Oxidative degradation in the solution of 3% H2O2-methanol 80:20 at 80°C for 6 h showed that amlodipine besylate degraded to 80.1%. After 14 days of expose in photostability chamber amlodipine besylate solution showed degradation of 32.2%. In electrochemical degradation after 9 hours of cyclization the beginning of amlodipine oxidation was shifted for 200 mV to more negative potentials, with the degradation of 66.5%. Mass spectrometry analysis confirmed the presence of dehydro amlodipine derivate with molecular formula C20H23N2O5Cl in oxidative and acidic conditions while in electrochemical degradation was detected in traces. [Projekat Ministarsva nauke Republike Srbije, br. 172013]

BACKGROUND Propolis is a complex resinous sticky substance that honeybees collect from buds and exudates of various plants. Owing to its versatile biological and pharmacological activities, propolis is widely used in medicines, cosmetics and foods. The aim of this study was to evaluate the cytotoxic and antioxidative effects of various ethanolic extracts of propolis ( EEPs) on human colon cancer cell line HCT-116 and compare them with their composition determined by HPLC-DAD. RESULTS The most abundant flavonoids in all samples were chrysin, pinocembrin and galangin (12.697-40.811 µg mg−1), while the main phenolic acids were caffeic acid, ferulic acid and isoferulic acid. Dose- and time-dependent inhibition of growth of HCT-116 cells was observed for all propolis samples, with IC50 values ranging from 26.33 to 143.09 µg mL−1. Differences in cytotoxic activity of propolis samples were associated with differences in their composition. All EEP samples reduced both superoxide anion radical and nitrite levels and also had strong DPPH-scavenging activity. CONCLUSION All tested propolis samples had pronounced cytotoxic and antioxidative activities. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The aim of the present paper was to investigate the reaction of quercetin, the flavonol very often used as a dietary supplement, with [AuCl4]− ions. The reaction was studied spectrophotometrically using the equimolar solutions in 1 : 1 water–methanol at pH ∼ 2. The spectrophotometric data indicated the formation of the products with an absorption maximum at 295 nm in all cases, characteristic of the oxidized forms of quercetin. HPLC coupled with DAD and LC-MS analysis of the reaction products suggested that the oxidation of quercetin resulted in the generation of similar metabolites including quinone and various oxidized quercetin–solvent adducts. In addition, cyclic voltammetric measurements confirmed that under applied experimental conditions, the reduction of Au(iii) to Au(0) took place. The reduction species in the reaction mixture were Au(iii) ions, while Au(i) disproportionates back to Au(iii) and Au(0). The newly generated Au(iii) ions further oxidized 3′,4′-dihydroxy groups of quercetin adducts obtained after first 2e− oxidation, giving the final reaction products. Based on the identification of reaction products, the reaction mechanism for the oxidation of quercetin in the presence of Au(iii) which involves two 2e− transfer processes was proposed. [ABSTRACT FROM AUTHOR]