Mutagenicity of paepalantine dimer and glycoside derivatives from Paepalanthus bromelioides

The first isocoumarin isolated from the methylene chloride extract of Paepalanthus bromelioides, named paepalantine (isocoumarin 1), was found to have antimicrobial activity; but, it is mutagenic clastogenic and cytotoxic. Two other isocoumarins, paepalantine-9-O-beta-D-glucopyranoside (isocoumarin 2) and paepalantine-9-O-beta-D-allopyranosyl(1-->6) glucopyranoside (isocoumarin 3) were isolated from the ethanolic extract. A fourth new isocoumarin, also isolated from the methylene chloride extract of the capitula of P. bromelioides, was characterized as an 8-8' dimer of paepalantine and denominated isocoumarin 4. The abilities of isocoumarins 2, 3 and 4 to induce mutations in Salmonella typhimurium strains TA97a, TA98, TA100 and TA102 were investigated. Mutagenic activity was observed in strain TA97a treated with isocoumarin 2 in the presence of S9 mixture. The substitution of H at position 9 by glucose or glucose-allose caused reductions in the mutagenic activities of paepalantine, indicating this to be an important site for these properties. (C) 2003 Elsevier Ltd. All rights reserved.

A new cytotoxic naphthoquinone from Paepalanthus latipes

Quinones constitute an important class of naturally occurring compounds. They are found in plants, fungi and bacteria. Large number of quinones has been associated with antitumor, antibacterial, antimalarial and antifungal activities. In this work we describe the isolation, structure determination and the cytotoxic index of a new 1,4-naphthoquinone isolated from the capitula of Paepalanthus latipes.

Mutagenic and cytotoxic effect of planifolin: A naphthopyranone dimer isolated from Paepalanthus planifolius

A naphthopyranone dimer, named planifolin, was isolated from a methylene chloride extract of the capitula of Paepalanthus planifolius Koern. The molecule (C31H26O10) appeared to be made up of two monomeric portions, semi-vioxanthin and paepalantine (an isocoumarin), linked by an ether bond, and it may possess several kinds of biological activity that can be related to its polyphenolic structure. Short-term tests that detect genetic damage can afford the information needed to evaluate carcinogenic risks of chemicals to humans. The Ames test, recommended for testing the mutagenicity of chemical compounds with potential pharmacological application, was used in the present study. The mutagenic activity was evaluated in Salmonella typhimurium strains TA100, TA98, TA102 and TA97a and the cytotoxic effect in McCoy cells. The in vitro cytotoxicity of planifolin to McCoy cells, tested in microculture with neutral red, showed a significant cytotoxic index (CI50) of 12.83 mu g/mL. Planifolin showed mutagenic activity for TA100, TA98 and TA97a. The results indicate that this new naphthopyranone dimer causes mutations by substitution and by addition and deletion of bases in the sequence of DNA. Moreover, its mutagenic potential was increased by metabolic activation. (c) 2005 Elsevier Ltd. All rights reserved.

Antioxidant activity of isocoumarins isolated from Paepalanthus bromelioides on mitochondria

The isocoumarins (1-50 mu M) 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 H2O2 accumulation and Fe2+ -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 H2O2. (C) 2007 Elsevier Ltd. All rights reserved.

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 Ca2+ 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 mu M 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 mu M Ca2+; inhibition of these processes was assessed in non-energized organelles in the presence of 300 mu M t-butyl hydroperoxide plus 500 mu M Ca2+. 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 Ca2+. 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. (c) 2006 Published by Elsevier B.V..

Ultrastructure of the intercellular protuberances in leaves of Paepalanthus superbus Ruhl. (Eriocaulaceae)

Folhas adultas de Paepalanthus superbus mostram protuberâncias intercelulares, entre a parede periclinal interna das células epidérmicas e superfície de células parenquimáticas; depósitos semelhantes ocorrem na superfície das células parenquimáticas do mesofilo. Estas protuberâncias são mais proeminentes ao redor de células parenquimáticas, formando uma estrutura que lembra uma cápsula gelatinosa. Testes histoquímicos com vermelho de rutênio evidenciam sua natureza péctica, com inclusões lipídicas dispersas, detectadas por sudan IV e sudan black B. Ultra-estruturalmente as protuberâncias mostram matriz fibrilar permeada por estruturas fimbriadas e tubulares, com margem distinta formada por estrutura membranosa. Nossos resultados sugerem que estas protuberâncias são derivadas de atividade secretora, sendo formadas após o desenvolvimento dos espaços intercelulares. em P. superbus esta estrutura pode representar uma especialização da parede celular, relacionada com adesão e mecanismos de transporte entre células.

Intestinal anti-inflammatory activity of paepalantine, an isocoumarin isolated from the capitula of Paepalanthus bromelioides, in the trinitrobenzenesulphonic acid model of rat colitis

The preventative intestinal anti-inflammatory activity of paepalantine, an isocoumarin isolated from the capitula of Paepalarithus bromelioides, was tested in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis. This was performed in two different experimental settings, i. e. when the colonic mucosa is intact or when the mucosa is in process of recovery after an initial insult. The results obtained revealed that the paepalantine pretreatment, at doses of 5 and 10 mg/kg, significantly attenuated the colonic damage induced by TNBS in both situations, as it was evidenced both histologically and biochemically. This beneficial effect was associated with an improvement in the colonic oxidative status, since paepalantine prevented the glutathione depletion that occurred as a consequence of the colonic inflammation. In addition, the intestinal anti-inflammatory effect exerted by this isocoumarin was associated with an inhibition of colonic nitric oxide activity, which is upregulated as a consequence of the inflammatory process. In conclusion, the preventative effect exerted by paepalantine in the TNBS model of rat colitis is probably related with its antioxidant properties.

Embryology and seed development of Blastocaulon scirpeum and Paepalanthus scleranthus (Eriocaulaceae)

The embryology and seed structure of Blastocaulon scirpeum (Mart.) Giul. and Paepalanthus scleranthus Ruhland were studied in order to contribute to the embryology of Eriocaulaceae and supply data for future taxonomic studies. Both species present: anther with 4-layered wall; conspicuous endothecium with fibrous thickenings; secretory tapetum with uninucleate cells; successive microsporogenesis forming isobilateral microspore tetrads; bicellular pollen grains; orthotropous, bitegmic and tenuinucellate ovule; micropyle formed by the inner integument alone; megagametophyte of the Polygonum type, with a conspicuous antipodal cyst; nuclear and starchy endosperm; reduced, undifferentiated, and bell-shaped embryo; operculate and endotestal seed; seed coat derived from the two ovule integuments; and tanniniferous endotegmen. In addition, Blastocaulon scirpeum shows a bisporangiate anther and a 3-layered ovary wall, while P. scleranthus presents a tetrasporangiate anther that becomes bisporangiate at maturity, and a 2-layered ovary wall. This investigation shows that the bisporangiate condition does not suffice to separate Blastocaulon from Paepalanthus, since it is common to both. It also indicates, based on several embryological aspects, the proximity of Eriocaulaceae and Xyridaceae, which comply mainly with the features presented by the other commelinid families. These results may be used in future cladistic analysis of the family, and contribute to a better understanding of its phylogeny.

Morphology and anatomy of inflorescence and inflorescence axis in Paepalanthus sect. Diphyomene Ruhland (Eriocaulaceae, Poales) and its taxonomic implications

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

HPLC-ESIMSn Profiling, Isolation, Structural Elucidation, and Evaluation of the Antioxidant Potential of Phenolics from Paepalanthus geniculatus

The methanol extract of the flowers of Paepalanthus geniculatus Kunth. showed radical-scavenging activity in the TEAC assay. An analytical approach based on HPLC:ESIMSn was applied to obtain the metabolite profile of this extract and led to the rapid identification of 19 polyphenolic compounds comprising flavonoids and naphthopyranones. The new naphthopyranone (10, 16), quercetagetin (1, 5, 7, 13), and galetine derivatives (9, 11, 17, 19), and a flavonol glucoside cyclodimer in the truxillate form (12), were identified. Compounds 2, 6, and 7 showed the highest antioxidant capacity and ability to affect the levels of intracellular ROS in human prostate cancer cells (PC3).

Avaliação da atividade mutagênica do extrato etanólico bruto de Paepalanthus latipes (Eriocaulaceae) e dos compostos flavonoídicos 7-metoxilados relacionados

Paepalanthus latipes (Silveira) é uma das plantas brasileiras nativas da Serra do Cipó, Minas Gerais, conhecida como sempre-vivas e muito exportada para os Estados Unidos, Europa e Japão, por seu valor ornamental. Poucos resultados são relatados quanto à atividade biológica destas plantas. Este trabalho teve como objetivo avaliar a atividade mutagênica do extrato etanólico bruto de P. latipes e de dois flavonóides 7-metoxilados dele isolados (7-metilquercetagetina e 7-metilquercetagetina-4'-O-β-D-glicopiranosídeo), através do teste de Ames, utilizando linhagens mutantes de Salmonella typhimurium TA98 e TA100. A atividade mutagênica das amostras testadas, em concentrações variando de 62,5 a 375 μg/placa, foi determinada com ativação metabólica (utilizando-se a fração microssomal S9) e na ausência dessa. Os resultados demonstraram que, tanto o extrato etanólico bruto de P. latipes quanto os flavonóides 7-metoxilados testados, não induziram atividade mutagênica nas linhagens TA98 e TA100.

Morphology and anatomy of the vegetative organs and scapes from Aphorocaulon (Paepalanthus, Eriocaulaceae)

Estudou-se a anatomia de raízes, caules, folhas e escapos de espécies de Paepalanthus subseção Aphorocaulon. Estas plantas apresentam caules reduzidos com folhas em roseta, de onde crescem os paracládios (sistemas de inflorescências). As espécies apresentam raízes com epiderme unisseriada e córtex com células isodiamétricas. Tanto os caules reduzidos como os paracládios apresentam espessamento resultante da atividade do periciclo, denominado Meristema de Espessamento Primário (MEP). Ambos apresentam estrutura anatômica semelhante. Os escapos apresentam endoderme descontínua, periciclo sinuoso, o córtex apresenta costelas salientes (5-6). As folhas apresentam células epidérmicas alongadas no sentido longitudinal com paredes levemente espessadas, estômatos somente na face abaxial, com câmara subestomática especializada, feixes vasculares colaterais com bainha dupla. Essas estruturas anatômicas são comuns para as espécies da subseção Aphorocaulon. Algumas características anatômicas observadas nestas espécies são típicas de plantas que crescem nos campos rupestres.

Chemical profile of the polar extract of Paepalanthus microphyllus (Guill.) Kunth (Eriocaulaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

n-alkanes from Paepalanthus Mart. species (Eriocaulaceae)

Este trabalho apresenta o estudo de substâncias apolares obtidas a partir de plantas pertencentes ao gênero Paepalanthus Mart. (Eriocaulaceae). Hidrocarbonetos alifáticos de cadeias longas lineares foram identificados por CG-DIC e CG-EM. Os resultados indicam que as espécies de Paepalanthus subg. Platycaulon apresentam perfil homogêneo, com cadeias carbônicas de n-alcanos variando de C25 a C31, com a maioria das amostras apresentando freqüências maiores dos homólogos C27 e C29. As espécies do subgênero Paepalocephalus podem ser diferenciadas pela distribuição dos n-alcanos principais. P. macrocephalus, uma espécie da subseção Aphorocaulon, apresenta perfil com alcanos de cadeia ímpar, enquanto P. denudatus e P. polyanthus, espécies da seção Actinocephalus, apresentam perfil bem distinto, com grande número de cadeias mais curtas e alta freqüência de cadeias com número par de carbonos, especialmente P. polyanthus. Os resultados obtidos indicam que a distribuição de nalcanos pode ser útil como caráter taxonômico, assim como as substâncias mais polares, como os flavonóides glicosilados.