Potent Antioxidant and Genoprotective Effects of Boeravinone G, a Rotenoid Isolated from Boerhaavia diffusa

Background and Aims: Free radicals are implicated in the aetiology of some gastrointestinal disorders such as gastric ulcer, colorectal cancer and inflammatory bowel disease. In the present study we investigated the antioxidant and genoprotective activity of some rotenoids (i.e. boeravinones) isolated from the roots of Boerhaavia diffusa, a plant used in the Ayurvedic medicine for the treatment of diseases affecting the gastrointestinal tract. Methods/Principal Findings: Antioxidant activity has been evaluated using both chemical (Electron Spin Resonance spectroscopy, ESR) and Caco-2 cells-based (TBARS and ROS) assays. DNA damage was evaluated by Comet assay, while pERK 1/2 and phospho-NF-kB p65 levels were estimated by western blot. Boeravinones G, D and H significantly reduced the signal intensity of ESR induced by hydroxyl radicals, suggesting a scavenging activity. Among rotenoids tested, boeravinone G exerted the most potent effect. Boeravinone G inhibited both TBARS and ROS formation induced by Fenton's reagent, increased SOD activity and reduced H 2O 2-induced DNA damage. Finally, boeravinone G reduced the levels of pERK 1 and phospho-NF-kB p65 (but not of pERK 2) increased by Fenton's reagent. Conclusions: It is concluded that boeravinone G exhibits an extraordinary potent antioxidant activity (significant effect in the nanomolar range). The MAP kinase and NF-kB pathways seem to be involved in the antioxidant effect of boeravinone G. Boeravinone G might be considered as lead compound for the development of drugs potentially useful against those pathologies whose aetiology is related to ROS-mediated injuries

The gut anaerobe Faecalibacterium prausnitzii uses an extracellular electron shuttle to grow at oxic-anoxic interphases

Faecalibacterium prausnitzii is one of the most abundant bacteria in the human gut ecosystem and it is an important supplier of butyrate to the colonic epithelium. Low numbers of faecalibacteria have been associated with inflammatory bowel disease. Despite being extremely oxygen sensitive, F. prausnitzii is found adherent to the gut mucosa where oxygen diffuses from epithelial cells. This paradox is now explained on the basis of gas tube experiments, flavin-dependent reduction of 5,5′-dithiobis-2-nitrobenzoate and microbial fuel cell experiments. The results show that F. prausnitzii employs an extracellular electron shuttle of flavins and thiols to transfer electrons to oxygen. Both compounds are present in the healthy human gut. Our observations may have important implications for the treatment of patients with Crohn's disease, for example, with flavin- or antioxidant rich diets, and they provide a novel key insight in host–microbe interactions at the gut barrier

Applying Geometric Morphometrics to Digital Reconstruction and Anatomical Investigation

Virtual imaging, image manipulation and morphometric methods are increasingly used in medicine and the natural sciences. Virtual imaging hardware and image manipulation software allows us to readily visualise, explore, alter, repair and study digital objects. This suite of equipment and tools combined with statistical tools for the study of form variation and covariation using Procrustes based analyses of landmark coordinates, geometric morphometrics, makes possible a wide range of studies of human variation pertinent to biomedicine. These tools for imaging, quantifying and analysing form have already led to new insights into organismal growth, development and evolution and offer exciting prospects in future biomedical applications. This chapter presents a review of commonly used methods for digital acquisition, extraction and landmarking of anatomical structures and of the common geometric morphometric statistical methods applied to investigate them: generalised Procrustes analysis to derive shape variables, principal component analysis to examine patterns of variation, multivariate regression to examine how form is influence

Avaliação dos níveis de peroxidação lipídica em células da mucosa cólica após aplicação de enemas com peróxido de hidrogênio: estudo experimental em ratos Evaluation of lipid peroxidation levels on mucosa colonic cells afther application of hydrogen peroxide in enemas: experimental study in rats

A aplicação de clisteres contendo peróxido de hidrogênio (H2O2) determina o aparecimento de quadros graves de colite, algumas vezes de evolução fatal. É possível que a colite induzida por H2O2 possa ocorrer pela quebra da barreira funcional do epitélio cólico por estresse oxidativo. Objetivo: Avaliar os níveis de peroxidação lipídica em células da mucosa cólica após instilação de H2O2 no reto excluso de trânsito fecal. Método: Vinte seis ratos Wistar machos foram submetidos a colostomia proximal terminal no cólon descendente e fístula mucosa distal. Os animais foram randomizados em dois grupos segundo o sacrifício ter sido realizado duas ou quatro semanas após a derivação intestinal. Cada grupo experimental foi dividido e dois subgrupos segundo aplicação de clisteres, em dias alternados, contendo solução fisiológica a 0,9% ou H2O2 a 3%. O diagnóstico de colite foi estabelecido por estudo histopatológico e os níveis de dano oxidativo tecidual pela dosagem de malondialdeído por espectrofotometria. Os resultados foram analisados com os testes de Mann-Whitney e Kruskal-Wallis, estabelecendo-se nível de significância de 5% (p<0,05). Resultados: Os níveis de malondialdeído nos irrigados com SF nos cólons com e sem trânsito fecal após duas e quatro semanas de irrigação foram de: 0,05 ± 0,006; 0,06 ± 0,006 e 0,05 ± 0,03, 0,08 ± 0,02, respectivamente. Os níveis de malondialdeído nos irrigados com H2O2, nos cólons com e sem trânsito, após duas e quatro semanas de irrigação foram de 0,070 ± 0,006; 0,077 ± 0,01 e 0,052 ± 0,01, 0,08 ± 0,04, respectivamente. Após duas semanas os níveis de malondialdeído foram maiores nos animais irrigados com H2O2 em relação ao grupo controle (p= 0,007 e p= 0,01, respectivamente). Após quatro semanas não houve diferenças significantes Não ocorreu variação nos níveis de malondialdeído com o decorrer tempo de irrigação. Conclusão: Clisteres com H2O2, podem determinar o aparecimento de colite por ocasionarem estresse oxidativo nas células epiteliais da mucosa intestinal.<br>The use of rectal enemas with hydrogen peroxide (H2O2) determines the onset of severe colitis, sometimes with fatal evolution. It is possible that H2O2-induced colitis can occur by damage to the functional epithelial barrier of the colon by oxidative stress. Objective: The aim of present study was evaluate the levels of lipid peroxidation in cells of the colonic mucosa after instillation of H2O2 into the rectum excluded from fecal transit. Method: Twenty six male Wistar rats were undergone to proximal terminal colostomy in the descending colon and distal mucous fistula. The animals were randomized in two experimental groups according to the sacrifice was made two or four weeks after diversion of the fecal stream. Each experimental group was divided into two subgroups second application of enemas containing saline solution 0.9% or 3% H2O2 on alternate days. The diagnosis of colitis was established by histopathology study and the oxidative damage by tissue levels of malondialdehyde quantified by spectrophotometry. The results were analyzed with the Mann-Whitney and Kruskal-Wallis test, adopting a significance level of 5% (p <0.05). Results: The levels of malondialdehyde in colon segments irrigated with saline, with and without fecal stream after two and four weeks of irrigation were: 0.05 ± 0.006, 0.06 ± 0.006 and 0.05 ± 0.03, 0.08 ± 0.02, respectively. The levels of malondialdehyde in colon segments irrigated with H2O2, in the colon with and without fecal stream, after two and four weeks of irrigation were 0.070 ± 0.006, 0.077 and 0.052 ± 0.01 ± 0.01, 0.08 ± 0.04, respectively . After two weeks the levels of malondialdehyde were higher on animals irrigated with H2O2 than control group (p = 0.007 and p = 0.01, respectively). After four weeks there were no significant differences in malondialdehyde levels related with the time of irrigation. Conclusion: Rectal enemas with H2O2, may determine the onset of colitis by oxidative stress on epithelial cells of intestinal mucosa

The flavonoid content and antiproliferative, hypoglycaemic, anti-inflammatory and free radical scavenging activities of <it>Annona dioica</it> St. Hill

<p>Abstract</p> <p>Background</p> <p><it>Annona dioica</it> St. Hill (Annonacaeae) is a Brazilian plant used in folk medicine for the treatment of several types of rheumatisms and diarrhoea. The focus of this work was to evaluate the <it>in vitro</it> antiproliferative and antioxidant activity and the <it>in vivo</it> hypoglycaemic and anti-inflammatory activity of <it>A. dioica</it> and identify the principal constituents of this plant.</p> <p>Methods</p> <p>The crude methanol extract (EAD) and hexane (HF), chloroform (CF), ethyl acetate (EAF) and hydromethanol fractions (HMF) were evaluated for free radical scavenging activity using the DPPH assay. The EAD and EAF were assayed for hypoglycaemic activity in rats. The EAD was tested in an antiproliferation assay and for anti-inflammatory effects in paw oedema, in addition to myeloperoxidase activity induced by carrageenan (Cg) in mice. The EAF was assayed using chromatographic methods.</p> <p>Results</p> <p>The fractionation of the EAF through chromatographic methods identified derivatives of the flavonoids quercetin and kaempferol. Among all the tested fractions, the ethyl acetate and hydromethanol fractions were the most potent, exhibiting an IC₅₀ of 8.53 and 10.57 μg/mL, respectively, which is comparable to that of the commercial antioxidant butylated hydroxytoluene (BHT). The oral administration of the EAD (100 mg/kg) and EAF (15 mg/kg) inhibited the increase of glucose levels, resulting in a hypoglycaemic effect. The EAD (30 to 300 mg/kg) exhibited an anti-oedematogenic effect in Cg-induced paw oedema in a time- and dose-dependent manner. The results showed a reduction of MPO activity by <it>A. dioica</it> 6 h after the induction of paw oedema at all doses tested with maximal inhibition at 300 mg/kg.</p> <p>Conclusions</p> <p>Our results reveal for the first time that compounds contained in the <it>A. dioica</it> leaves exert anti-inflammatory, hypoglycaemic, antiproliferative, and antioxidant effects. The antioxidant activity may be associated with the presence of flavonoids.</p