Use of sildenafil and L-arginine in an experimental rat model for the prevention of neonatal necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) has a 45% mortality in neonatal intensive care units. This paper aimed to evaluate the isolated and combined effects of sildenafil and L-arginine in the prevention of necrotizing enterocolitis. Neonatal rats were fed formula milk and submitted to hypoxia under a 100% N2 atmosphere for 70 s. Then, animals were subjected to hypothermia (4 °C for 10 min), twice a day for 3 days. Forty neonatal rats were divided into five groups: negative control-not submitted to the protocol (n = 5), sildenafil group-NEC protocol (n = 9), L-arginine group-NEC protocol (n = 9), L-arginine and sildenafil group-NEC protocol (n = 9) and positive control-NEC protocol and intraperitoneal saline solution (n = 8). Jejunum and terminal ileus were removed for histopathologic and immunohistochemical Ki-67 analysis. Kruskal-Wallis test was used to analyze mortality, survival, body weight, intestinal injury score and Ki-67 proliferation index. All animals submitted to the protocol developed enterocolitis. Mortality rate was higher in group that received only L-arginine (p = 0.0293). The Ki-67 analysis showed a higher proliferative index in groups that received interventional drugs (p = 0.017). In conclusion, sildenafil and L-arginine were not effective to reduce intestinal injury.

The mesoionic compound MI-D changes energy metabolism and induces apoptosis in T98G glioma cells.

The mesoionic compound 4-phenyl-5-(4-nitro-cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride (MI-D) impairs mitochondrial oxidative phosphorylation and has a significant antitumour effect against hepatocarcinoma and melanoma. This study evaluated the cytotoxic effect of MI-D on T98G glioblastoma cells and investigated whether the impairment of oxidative phosphorylation promoted by MI-D is relevant to its cytotoxic effect. The effects of MI-D on T98G cells cultured in high glucose Dulbecco's modified Eagle's medium (DMEM) HG (glycolysis-dependent) and galactose plus glutamine-supplemented Dulbecco's modified Eagle's medium (DMEM) GAL (oxidative phosphorylation-dependent) were compared. T98G cells grown in DMEM GAL medium exhibited higher respiration rates and citrate synthase activity and lower lactate levels, confirming the metabolic shift to oxidative phosphorylation in these cells. MI-D significantly decreased the cell viability in a dose-dependent manner in both media; however, T98G cells cultured in DMEM GAL medium were more susceptible. The mesoionic significantly inhibited mitochondrial oxidative phosphorylation of glioma cells in both media. At the same time, lactate levels were not altered, indicating an absence of compensatory glycolysis activation. Additionally, MI-D increased the citrate synthase activity of cells in both media, which in DMEM HG-cultivated cells was followed by citrate accumulation. Apoptosis dependent on caspase-3 mediated the toxicity of MI-D on T98G cells. The higher susceptibility of glioma cells cultured in DMEM GAL medium to MI-D indicates that the impairment of mitochondrial functions is involved in mesoionic cytotoxicity. The results of this study indicate the potential use of MI-D for glioblastoma treatment.

Changes in the composition and structure of cell wall polysaccharides from Artemisia annua in response to salt stress.

Artemisia annua is cultivated mainly for isolation of artemisinin, a potent antimalarial compound. Moderate salt stress has been proved to increase the artemisinin synthesis by the plant. The aim of this study was to evaluate the influence of salt stress on physiological parameters and cell wall polysaccharides of A. annua. Plants subjected to salt stress displayed reduction in the biomass and length and showed high damage of cellular membranes. Cell wall polysaccharides extracted from aerial parts with hot water, EDTA and NaOH also exhibited modifications in the yield and monosaccharide composition. The main changes were found in the pectic polysaccharides: increase of homogalacturonan domain, increase of neutral side chains and increase in the methyl esterification. 1H NMR analyses of pectins indicated that for A. annua, arabinans have an important role in coping with salt stress. Hemicellulose domain was also modified under salt stress, with increased xylose contents. The results indicated adaptations in the cell wall of A. annua under salt stress.

Characterization of cell wall polysaccharides from Sicana odorifera fruit and structural analysis of a galactan-rich fraction pectins as side chains.

Sicana odorifera is a Brazilian native fruit. In this work, cell wall polysaccharides from S. odorifera pulp were isolated by sequential extraction with water, citric acid, and sodium hydroxide solutions. The monosaccharide composition of crude polysaccharide fractions was determined. The aqueous fractions displayed the highest yields and they were constituted by pectins, having mainly galactans as side chains. The citric acid fraction (SCA) had galactose as the main component. The hemicellulosic fractions consisted mainly of xylose, mannose, galactose, and glucose, suggesting the presence of xyloglucans, xylans and mannans. The SCA fraction was further purified, resulting in a linear galactan (SCAI2). NMR and methylation analysis showed that SCAI2 was a ß-(1→4) d-galactan with molar mass of 17,560 g/mol, determined by light scattering. The presence of a linear galactan in free form in fruits is unusual because these polymers usually occur as side chains of type I rhamnogalacturonans.

Gastroprotective effects and structural characterization of a pectic fraction isolated from Artemisia campestris subsp maritima.

The aim of this study was to investigate the chemical structure and biological activity of a pectic fraction isolated from the aerial parts of A. campestris L. subsp. maritima Arcangeli. The chemical and spectroscopic analyses of the pectic fraction (ACP-E10) demonstrated that ACP-E10 was composed of homogalacturonan (HG) (60%) and rhamnogalacturonan-I (RG-I) (29%) regions. Side chains of the RG-I included mainly branched arabinans and type II arabinogalactans (AG-II). The molar mass of ACP-E10 determined by HPSEC-MALLS was 16,600g/mol. ACP-E10 was evaluated for its gastroprotective effect against ethanol-induced gastric lesions in rats. Oral pretreatment of animals with ACP-E10 (0.3, 3 and 30mg/kg) significantly reduced gastric lesions by 77±7.9%, 55±11.1% and 65±11.8%. ACP-E10 also maintained mucus and glutathione (GSH) contents in the gastric mucosa. In addition, ACP-E10 demonstrated antioxidant activity in vitro by the DPPH assay. These results demonstrated that the pectin from A. campestris had significant gastroprotective effects in vivo, which were likely attributable to their capacity to increase the protective defenses of gastric mucosa.

Inulin-type fructan and infusion of Artemisia vulgaris protect the liver against carbon tetrachloride-induced liver injury.

BACKGROUND: Infusions of aerial parts of Artemisia vulgaris L. (Asteraceae) are used in herbal medicine to treat several disorders, including hepatosis. PURPOSE: Evaluation of in vivo hepatoprotective effects of A. vulgaris infusion (VI) and inulin (VPI; i.e., the major polysaccharide of VI). STUDY DESIGN: The hepatoprotective effect of A. vulgaris extracts on carbon tetrachloride (CCl4)-induced hepatotoxicity and the probable mechanism involved in this protection were investigated in mice. METHODS: A. vulgaris infusion (VI) was prepared according to folk medicine using the aerial parts of the plant. Carbohydrate, protein, and total phenolic content was determined in VI, and its phenolic profile was determined by high-performance liquid chromatography (HPLC). Male Swiss mice were orally pretreated for 7 days with VI or VPI (once per day). On days 6 and 7 of treatment, the mice were intraperitoneally challenged with CCl4. Liver and blood were collected and markers of hepatic damage in plasma and oxidative stress in the liver were analyzed. Hepatic histology and inflammatory parameters were also studied in the liver. The scavenging activity of VI and VPI were evaluated in vitro using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. RESULTS: VI contained 40% carbohydrates, 2.9% proteins and 9.8% phenolic compounds. The HPLC fingerprint analysis of VI revealed chlorogenic, caffeic and dicaffeoylquinic acids as major low-molar-mass constituents. Oral pretreatment with VI and VPI significantly attenuated CCl4-induced liver damage, reduced the activity of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) in plasma, and prevented reactive oxygen species accumulation and lipid peroxidation in the liver. Comparisons with the CCl4-treated group showed that VI and VPI completely prevented necrosis, increased the levels of reduced glutathione (GSH), and reduced tumor necrosis factor alpha (TNF-α) level in the liver. VI and VPI also exhibited high radical scavenging activity in vitro. CONCLUSION: VI and VPI had remarkable hepatoprotective effects in vivo, which were likely attributable to antioxidant and immunomodulatory properties. The present findings support the traditional use of A. vulgaris infusion for the treatment of hepatic disorders.

Artemisia absinthium and Artemisia vulgaris: a comparative study of infusion polysaccharides.

The aerial parts of Artemisia absinthium and Artemisia vulgaris are used in infusions for the treatment of several diseases. Besides secondary metabolites, carbohydrates are also extracted with hot water and are present in the infusions. The plant carbohydrates exhibit several of therapeutic properties and their biological functions are related to chemical structure. In this study, the polysaccharides from infusions of the aerial parts of A. absinthium and A. vulgaris were isolated and characterized. In the A. absinthium infusion, a type II arabinogalactan was isolated. The polysaccharide had a Gal:Ara ratio of 2.3:1, and most of the galactose was (1 → 3)- and (1 → 6)-linked, as typically found in type II arabinogalactans. In the A. vulgaris infusion, an inulin-type fructan was the main polysaccharide. NMR analysis confirmed the structure of the polymer, which is composed of a chain of fructosyl units ß-(2 ← 1) linked to a starting α-d-glucose unit.