Effect of Byrsonima crassa and phenolic constituents on Helicobacter pylori-induced neutrophils oxidative burst.

Byrsonima crassa Niedenzu (Malpighiaceae) is used in Brazilian folk medicine for the treatment of diseases related mainly to gastric ulcers. In a previous study, our group described the gastric protective effect of the methanolic extract from the leaves of B. crassa. The present study was carried out to investigate the effects of methanolic extract and its phenolic compounds on the respiratory burst of neutrophils stimulated by H. pylori using a luminol-based chemiluminescence assay as well as their anti-H. pylori activity. The suppressive activity on oxidative burst of H. pylori-stimulated neutrophils was in the order of methyl gallate > (+)-catechin > methanol extract > quercetin 3-O-α-l-arabinopyranoside > quercetin 3-O-ß-d-galactopyranoside > amentoflavone. Methyl gallate, compound that induced the highest suppressive activity with IC(50) value of 3.4 µg/mL, did not show anti-H. pylori activity. B. crassa could be considered as a potential source of natural antioxidant in gastric ulcers by attenuating the effects on the damage to gastric mucosa caused by neutrophil generated reactive oxygen species, even when H. pylori displays its evasion mechanisms.

Anti-Helicobacter pylori activity and immunostimulatory effect of extracts from Byrsonima crassa Nied. (Malpighiaceae).

BACKGROUND: Several in vitro studies have looked at the effect of medicinal plant extracts against Helicobacter pylori (H. pylori). Regardless of the popular use of Byrsonima crassa (B. crassa) as antiemetic, diuretic, febrifuge, to treat diarrhea, gastritis and ulcers, there is no data on its effects against H. pylori. In this study, we evaluated the anti-H. pylori of B. crassa leaves extracts and its effects on reactive oxygen/nitrogen intermediates induction by murine peritoneal macrophages. METHODS: The minimal inhibitory concentration (MIC) was determined by broth microdilution method and the production of hydrogen peroxide (H2O2) and nitric oxide (NO) by the horseradish peroxidase-dependent oxidation of phenol red and Griess reaction, respectively. RESULTS: The methanolic (MeOH) and chloroformic (CHCl3) extracts inhibit, in vitro, the growth of H. pylori with MIC value of 1024 microg/ml. The MeOH extract induced the production H2O2 and NO, but CHCl3 extract only NO. CONCLUSION: Based in our results, B. crassa can be considered a source of compounds with anti-H. pylori activity, but its use should be done with caution in treatment of the gastritis and peptic ulcers, since the reactive oxygen/nitrogen intermediates are involved in the pathogenesis of gastric mucosal injury induced by ulcerogenic agents and H. pylori infections.

Ascorbic acid potentiates the cytotoxicity of the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin.

The interaction of ascorbic acid with 5-methoxy-3,4-dehydroxanthomegnin, an 1,4-naphthoquinone, was investigated using the cytotoxic index for McCoy cells by neutral red assay. The synergistic effect was observed when such compounds were added simultaneously, most probably due to hydrogen peroxide being generated by ascorbate-driven 5-methoxy-3,4-dehydroxanthomegnin redox cycling. Incubation of cells in the presence of 5-methoxy-3,4-dehydroxanthomegnin/ascorbic acid/catalase, an enzyme that destroys H2O2, resulted in an increase of cell survival, reinforcing the involvement of hydrogen peroxide generated as an important oxidizing agent that kills McCoy cells.

Antioxidant activity of isocoumarins isolated from Paepalanthus bromelioides on mitochondria.

The isocoumarins (1-50 microM) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8'-paepalantine dimer, and vioxanthin isolated from Paepalanthus bromelioides, were assessed for antioxidant activity using isolated rat liver mitochondria and non-mitochondrial systems, and compared with the flavonoid quercetin. The paepalantine and paepalantine dimers, but not vioxanthin, were effective at scavenging both 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) and superoxide (O(2)(-)) radicals in non-mitochondrial systems, and protected mitochondria from tert-butylhydroperoxide-induced H(2)O(2) accumulation and Fe(2+)-citrate-mediated mitochondrial membrane lipid peroxidation, with almost the same potency as quercetin. These results point towards paepalantine, followed by paepalantine dimer, as being a powerful agent affording protection, apparently via O(2)(-) scavenging, from oxidative stress conditions imposed on mitochondria, the main intracellular source and target of those reactive oxygen species. This strong antioxidant action of paepalantine was reproduced in HepG2 cells exposed to oxidative stress condition induced by H(2)O(2).

Effects of isocoumarins isolated from Paepalanthus bromelioides on mitochondria: uncoupling, and induction/inhibition of mitochondrial permeability transition.

Isolated mitochondria may undergo uncoupling, and in presence of Ca(2+) at different conditions, a mitochondrial permeability transition (MPT) linked to protein thiol oxidation, and demonstrated by CsA-sensitive mitochondrial swelling; these processes may cause cell death either by necrosis or by apoptosis. Isocoumarins isolated from the Brazilian plant Paepalanthus bromelioides (Eriocaulaceae) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8'-paepalantine dimer, and vioxanthin were assayed at 1-50 microM on isolated rat liver mitochondria, for respiration, MPT, protein thiol oxidation, and interaction with the mitochondrial membrane using 1,6-diphenyl-1,3,5-hexatriene (DPH). The isocoumarins did not significantly affect state 3 respiration of succinate-energized mitochondria; they did however, stimulate 4 respiration, indicating mitochondrial uncoupling. Induction of MPT and protein thiol oxidation were assessed in succinate-energized mitochondria exposed to 10 microM Ca(2+); inhibition of these processes was assessed in non-energized organelles in the presence of 300 microM t-butyl hydroperoxide plus 500 microM Ca(2+). Only paepalantine was an effective MPT/protein thiol oxidation inducer, also releasing cytochrome c from mitochondria; the protein thiol oxidation, unlike mitochondrial swelling, was neither inhibited by CsA nor dependent on the presence of Ca(2+). Vioxanthin was an effective inhibitor of MPT/protein thiol oxidation. All isocoumarins inserted deeply into the mitochondrial membrane, but only paepalantine dimer and vioxantin decreased the membrane's fluidity. A direct reaction with mitochondrial membrane protein thiols, involving an oxidation of these groups, is proposed to account for MPT induction by paepalantine, while a restriction of oxidation of these same thiol groups imposed by the decrease of membrane fluidity, is proposed to account for MPT inhibition by vioxanthin.

Cytotoxicity of two novel formulations of calcium phosphate cements: a comparative in vitro study.

The purpose was to evaluate the cytotoxicity of two novel formulations (alpha and beta) of calcium phosphate cements. Positive control, represented by a commercial hydroxyapatite cement, and negative control were included for comparative purposes. A continuous lineage of fibroblastic cells was used, and the effect of the tested materials on both cell proliferation and viability was assessed by counting cell number on hemocytometer and by the trypan blue exclusion test, respectively. Study design attempted to simulate clinical use by allowing direct and indirect contact of cells and cements. Results were analyzed by the Kruskal-Wallis test and indicated that the beta formulation was extremely cytotoxic (P < 0.001), because this material induced the greatest reduction on cell proliferation and viability. The alpha formulation behaved similarly to the positive control regarding its effect on cell proliferation and viability. Thus, it is concluded that alpha formulation has promise for further evaluation of its behavior in vivo.

Screening for antimicrobial activity of natural products using a microplate photometer

The microdilution technique, using a microplate photometer, to determine the minimal inhibitory concentration (MIC) for a natural product was compared to the serial tube dilution method. The MIC obtained for Paepalantine against S. aureus was the same by the two methods, showing an antimicrobial effect similar to chloramphenicol.

Cervicovaginal aerobic microflora of women with spontaneous abortion or preterm delivery in Araraquara-Brazil

Microbiological routine exams of endocervix and vaginal specimens of 22 women with clinical history of recent spontaneous abortion or premature rupture of membranes were accomplished. "Chlamydia thachomatis", "Streptococcus pyogenes", "Streptococcus agalactie", "Candida" sp and "Gardnerela vaginalis" were recovered from 54.5 (per cent) (12) of the women. "Ureoplasma urealyticum" was frequently isolated (45.5 (per cent)) but 5 out of 22 qualitative investigation on genital microflora in pregnant women, since it is likely to influence onm pregnancy outcome.

Urina de primeiro jato versus jato médio para detecçäo de Ureaplasma urealyticum no trato urinário / First-void versus midstream urine culture for detection of ureaplasma urealyticum in the urinary tract

Resumo: Cultura quantitativa para Ureaplasma urealyticum foi realizada a partir de urina colhida, após antissepsia, de primeiro jato e jato médio com o objetivo de detectar a presença desse molicute no trato urinário. Os resultados, expressos em CCu (color changing units), mostraram que 14 (63 por cento) dos pacientes com cultura positiva albergavam o microrganismo em quantidades iguais ou superiores a 10 (elevado a sete) CCU/ml nas porçöes de urina obtidas de primeiro jato e jato médio. Näo foram observadas alteraçöes químicas ou microscópicaas (proteinas, leucócitos) nos materiais examinados. U. urealyticum em amostra de urina colhida de jato médio, mesmo em quantidade considerável, näo elucida as patogenicidade desse microrganismo (au)