Intracellular ROS Generation Mediates Maleimide-induced Cytotoxicity in Leukemia Cells.

Maleimides consist of an important class of compounds easily synthesized with multiple functional group modification that provides expressive pharmacological properties including, antitumoral activity, mediated mainly by oxidative stress. For this reason, the present study was designed to evaluate the cytotoxicity and the role of reactive oxygen species (ROS) in maleimide-induced cell death. Cell viability assays were performed to determine the cell death type in leukemia cell line induced by the compounds. The oxidative stress in maleimidetreated cells was characterized by antioxidant enzymes activities, intracellular ROS generation, and lipid peroxidation. In addition, we evaluated mitochondrial membrane potential and ATP level. Maleimide derivatives exhibited cytotoxic effects in leukemia cells with significantly increased ROS generation. However, cell viability was partly restored by catalase-treated cells. Caspases activities and caspase-independent key genes related to apoptosis were not altered by maleimides, suggesting necrosis as the main cell death process. Maleimide-induced necrosis was associated with oxidative stress, as an imbalance between ROS levels and glutathione reductase (GR) activity. This damage was also demonstrated by loss of mitochondrial membrane potential (MMP) and ATP depletion in cells treated with maleimide derivatives. These findings strongly confirmed that maleimide derivatives promoted cell death in leukemia cells triggered by oxidative stress, indicating that these compounds might be promising antitumor agents or lead molecules.

N-phenylmaleimide derivatives as mimetic agents of the pro-inflammatory process: myeloperoxidase activation.

Myeloperoxidase (MPO) is an important enzyme that catalyzes the reaction between hydrogen peroxide and chloride to generate hypochlorous acid, which oxidizes a range of biomolecules and has been associated with inflammatory diseases. The synthetic compounds N-phenylmaleimide (NFM) and 4-methyl-N-phenylmaleimide (Me-NFM) increased the MPO activity in vitro (of isolated enzyme and in isolated cells after animal treatment) and in vivo assays. MPO-induction may represent a good model system to investigate the molecular and cellular mechanisms of oxidative cell injury induced by activated neutrophils, and the interactions between damaging species involved in the respiratory burst.

Anti-inflammatory, antinociceptive, and antipyretic effects of methanol extract of Cariniana rubra stem bark in animal models.

Cariniana rubra Miers (Lecythidaceae), popularly known as "jequitibá-vermelho'', is a large Brazilian tree whose bark is used in infusion and decoction for the treatment of inflammatory conditions. This study aims to assess the anti-inflammatory, antinociceptive, and antipyretic effects of Cariniana rubra methanolic stem bark extract (EM Cr) using experimental animals. Anti-inflammatory activity of EM Cr was tested on carrageenan and dextran-induced rat paw edema, carrageenan-induced pleurisy in rats and acetic acid-increase vascular permeability in mice. Antinociceptive and antipyretic activities were evaluated using acetic acid-induced writhing, formalin and hot-plate tests in mice, as well as brewer's yeast-induced pyrexia in rats. The extract inhibitied carrageenan and dextran-induced edema, reduced exudate volume and leukocyte migration on the carrageenan-induced pleurisy and on the vascular permeability increase induced by acetic acid. The EM Cr inhibited nociception on the acetic acid-induced writhing and in the second phase of formalin test, and decreased rectal temperature. It was, however, inactive against thermal nociception.Phytochemical analysis with EM Cr showed the occurrence of saponins, triterpenes, sterols and phenolic compounds. Phytosterols (ß-sitosterol, stigmasterol), pentacyclic triterpenes (α- and ß-amyrin as a mixture), arjunolic acid, a phytosterol glycoside (sitosterol 3-O-ß-D-glucopyranoside), and triterpenoid saponins (28-ß-glucopyranosyl-23-O-acetyl arjunolic acid; 3-O-ß-glucopyranosyl arjunolic acid and 28-O-[α-L-Rhamnopyranosyl-(1→2)-ß-glucopyranosyl]-23- O-acetyl arjunolic acid) were the main identified compounds. It can be presumed that EM Cr caused their effects by inhibiting the liberation and/or action of different inflammatory mediators. These findings support the traditional use of Cariniana rubra preparations to treat inflammation.

Anti-inflammatory, antinociceptive, and antipyretic effects of methanol extract of Cariniana rubra stem bark in animal models

Cariniana rubra Miers (Lecythidaceae), popularly known as "jequitibá-vermelho'', is a large Brazilian tree whose bark is used in infusion and decoction for the treatment of inflammatory conditions. This study aims to assess the anti-inflammatory, antinociceptive, and antipyretic effects of Cariniana rubra methanolic stem bark extract (EM Cr) using experimental animals. Anti-inflammatory activity of EM Cr was tested on carrageenan and dextran-induced rat paw edema, carrageenan-induced pleurisy in rats and acetic acid-increase vascular permeability in mice. Antinociceptive and antipyretic activities were evaluated using acetic acid-induced writhing, formalin and hot-plate tests in mice, as well as brewer's yeast-induced pyrexia in rats. The extract inhibitied carrageenan and dextran-induced edema, reduced exudate volume and leukocyte migration on the carrageenan-induced pleurisy and on the vascular permeability increase induced by acetic acid. The EM Cr inhibited nociception on the acetic acid-induced writhing and in the second phase of formalin test, and decreased rectal temperature. It was, however, inactive against thermal nociception.Phytochemical analysis with EM Cr showed the occurrence of saponins, triterpenes, sterols and phenolic compounds. Phytosterols (β-sitosterol, stigmasterol), pentacyclic triterpenes (α- and β-amyrin as a mixture), arjunolic acid, a phytosterol glycoside (sitosterol 3-O-β-D-glucopyranoside), and triterpenoid saponins (28-β-glucopyranosyl-23-O-acetyl arjunolic acid; 3-O-β-glucopyranosyl arjunolic acid and 28-O-[α-L-Rhamnopyranosyl-(1→2)-β-glucopyranosyl]-23- O-acetyl arjunolic acid) were the main identified compounds. It can be presumed that EM Cr caused their effects by inhibiting the liberation and/or action of different inflammatory mediators. These findings support the traditional use of Cariniana rubra preparations to treat inflammation.

Cariniana rubra Miers (Lecythidaceae), popularmente conhecido como "jequitibá-vermelho'', é uma árvore brasileira de grande porte, cuja casca é utilizada nas formas de infusão e decocção para o tratamento de condições inflamatórias. Os efeitos antiinflamatório, antinociceptivo e antipirético do extrato metanólico da casca do caule de Cariniana rubra (EM Cr) foram avaliados em animais experimentais. A atividade antiinflamatória do EM Cr foi testada nos modelos de edema depata induzido por carragenina e dextrana em ratos, pleurisia induzida por carragenina em ratos e permeabilidade vascular aumentada por ácido acético em ratos. As atividades antinociceptiva e antipirética foram avaliadas utilizando os modelos de nocicepções induzidos por ácido acético e formalina, placa quente em camundongos e de pirexia, pela injeção de levedura de cerveja em ratos. O extrato inibiu o edema induzido porcarragenina e dextrana, reduziu o volume de exsudato e a migração de leucócitos na pleurisia induzida por carragenina eo aumento da permeabilidade vascular induzida por ácidoacético. O EM Cr inibiu a nocicepção nas contorções induzidas por ácido acético e na segunda fase do teste de formalina e diminuiu a temperatura retal. No entanto, foi inefetivo no teste da placa quente. A análise química por via úmida deu resultados positivos para saponinas, triterpenos, esteroides e compostos fenólicos. Fitosteróis e triterpenóides pentacíclicos (β-sitosterol, estigmasterol, α and β-amirinas em mistura e ácido arjunólico) e as saponinas triterpenoidais: 3-O-β-D-glucopiranosideo de sitosterol; ácido arjunólico 28-β-glucopiranosila-23-O-acetila; ácido arjunólico 3-O-β-glucopiranosila e ácido arjunólico 28-O-[α-L-rhamnopiranosil-(1→2)-β-D-glucopiranosila]-23-O-acetila. Pode-se presumir que os efeitos do EM Cr foram causados pela inibição da liberação e/ou ação de diversos mediadores inflamatórios. Estes resultados validam o uso tradicional das preparações caseiras de Cariniana rubra para tratar a inflamação.

Vasorelaxant action of N-p-nitrophenylmaleimide in the isolated rat mesenteric artery.

The vasorelaxant response of N-p-nitrophenylmaleimide (4-NO2-NPM) was evaluated. The mesenteric rings (1-2 mm i.d.) were suspended by cotton thread for isometric tension recordings in a Tyrode's solution at 37 degrees C and gassed with a mixture of 95% O2 and 5% CO2, under a resting tension of 0.75 g. 4-NO2-NPM induced relaxation in mesenteric rings pre-contracted with phenylephrine (Phe; 10 microM, pD2 = 6.7 +/- 0.3) or KCl (80 mM, pD2 = 3.9 +/- 0.2). This effect was significantly attenuated after removal of the vascular endothelium, N(G)-nitro L-arginine methyl ester (L-NAME; 100 microM), atropine (1 microM), indomethacin (10 microM), L-NAME + indomethacin or 1H-[1,2,3]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 microM). L-Arginine (1 mM) reversed the inhibitory effect of L-NAME. In endothelium-intact preparations pre-incubated with 20 mM KCl, tetraethylammonium bromide (TEA; 1 mM) or glibenclamide (Glib; 10 microM), the vasorelaxant effect was significantly attenuated when compared to controls (endothelium intact). In denuded rings, separate incubation with 20 mM KCl, TEA or Glib did not change the relaxation when compared with that obtained in denuded rings. 4-NO2-NPM inhibited in a concentration-dependent and non-competitive manner the concentration-response curves induced by CaCl2. In calcium-free medium, the transient contractions induced by Phe (10 microM) or caffeine (20 mM) were inhibited. The relaxant effect induced by 4-NO2-NPM appeared to be due to endothelial muscarinic receptors activation, NO and prostacyclin release and K(ATP) and BK(Ca) (Ca(2+)-activated K+ channels) endothelium-dependent activation. Inhibition of the Ca2+ influx and inhibition of the Ca2+ release from intracellular IP3- and caffeine-sensitive stores are also involved in the vasorelaxation.

Evaluation of the antifungal activity and mode of action of Lafoensia pacari A. St.-Hil., Lythraceae, stem-bark extracts, fractions and ellagic acid / Avaliação da atividade antifúngica e modo de ação dos extratos da entrecasca, frações e ácido elágico de Lafoensia pacari A. St.-Hil., Lythraceae

Stem-bark extracts, fractions and the isolated constituent, ellagic acid of Lafoensia pacari St. Hil. (Lythraceae) were in vitro assayed for antifungal activity against a panel of yeasts, hialohyphomycetes as well as dermatophytes with the microbroth dilution method. The EtOH extract and its fractions and ellagic acid exhibited activity against Candida spp and Saccharomyces cerevisiae with MIC values between 250-1000 µg/mL, but they showed no action against filamentous fungi and dermatophytes (MIC>1000 µg/mL). Active extracts were evaluated in Neurospora crassa hyphal growth inhibition and sorbitol assays and then the effect of ergosterol on the MIC of ellagic acid was studied. The active extracts and its fractions and ellagic acid showed a blotchy zone around the paper disk and induced malformations of the hypha. Besides, MIC of the ellagic acid against the Saccharomyces cerevisiae was raised from 62 to 250 µg/mL in the presence of sorbitol 0.8 M, suggesting that the ellagic acid would probably exert its action on fungal cell wall. These results indicate that ellagic acid might be the main active antifungal compound of Lafoensia pacari and further suggest that the mode of antifungal action of these extracts and ellagic acid could be associated with the inhibition of fungal cell wall.

Os extratos, frações e ácido elágico, isolados da entrecasca de Lafoensia pacari A. St.-Hil., Lythraceae, foram testados in vitro para atividade antifúngica, frente a um painel de leveduras, hialo-hifomicetos e dermatófitos, utilizando o método de microdiluição. O extrato EtOH, frações e ácido elágico exibiram atividade contra Candida spp. e Saccharomyces cerevisiae com valores de CIM entre 250-1000 µg/mL, porιm não mostraram ação contra fungos filamentosos e dermatófitos (CIM>1000 µg/mL). Os extratos ativos foram avaliados nos ensaios de inibição do crescimento das hifas de Neurospora crassa, no teste do sorbitol, e pelo estudo do efeito do ergosterol na CIM do ácido elágico. Os extratos ativos, frações e ácido elágico mostraram zonas manchadas ao redor dos discos de papel e induziram malformações nas hifas. Além disso, a CIM do ácido elágico contra Saccharomyces cerevisiae passou de 62 para 250 µg/mL na presença do sorbitol 0,8 M, sugerindo que o ácido elágico provavelmente poderia exercer ação na parede celular fúngica. Esses resultados indicam que o ácido elágico pode ser o principal composto antifúngico de Lafoensia pacari, sugerindo que o modo de ação antifúngico desses extratos e ácido elágico poderia estar associado à inibição da parede celular fúngica.

Evaluation of the relaxant action of some Brazilian medicinal plants in isolated guinea-pig ileum and rat duodenum.

PURPOSE: The present study aimed to evaluate the possible antispasmodic activity in vitro of methanolic extracts (ME) of six Brazilian medicinal plants. METHODS: The extracts were evaluated on isolated guinea-pig ileum and rat duodenum preparations. RESULTS: Rubus imperialis, Maytenus robusta, Ipomoea pes caprae and Epidendrum mosenii did not inhibit the contractile response elicited by acetylcholine on guinea-pig ileum. On the other hand, ME from Calophyllum brasiliense and Cynara scolymus exhibited significant inhibitory activity for the contractile response elicited by acetylcholine on guinea-pig ileum and on rat duodenum in a noncompetitive and concentration-dependent manner. CONCLUSIONS: The current study suggests that, of the six medicinal plants evaluated, only the ME of Calophyllum brasiliense and Cynara scolymus show probable antispasmodic activity, confirming and justifying their use in folk medicine for the treatment of intestinal disorders.

Antimicrobial activity of fractions and compounds from Calophyllumbrasiliense (Clusiaceae/Guttiferae).

Calophyllum brasiliense (Clusiaceae/Guttiferae) is a native Brazilian medicinal plant traditionally used against several diseases, including infectious pathologies. Crude methanolic extracts (CME) and two fractions, denoted non-polar (soluble in chloroform) and polar (nonsoluble in chloroform), were prepared from different parts of the plant (roots, stems, leaves, flowers and fruits) and studied. The following compounds were isolated and tested against pathogenic bacteria and yeasts by determination of the minimal inhibitory concentration (MIC): brasiliensic acid (1), gallic acid (2), epicatechin (3), protocatechuic acid (4), friedelin (5) and 1,5-dihydroxyxanthone (6). The results indicated that all the parts of the plant exhibited antimicrobial activity against Gram-positive bacteria, which are selectively inhibited by components of C. brasiliense. No activity was observed against Gram-negative bacteria and yeasts tested. Regarding the isolated compounds, substance 4 showed antimicrobial activity against all the tested microorganisms, whereas compound 6 exhibited antimicrobial activity only against Gram-positive bacteria. The results from the current study confirm and justify the popular use of this plant to treat infectious processes.