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

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

Anatomia do escapo floral de espécies brasileiras de Paepalanthus subgênero Platycaulon (Eriocaulaceae)

Foi estudada a anatomia dos escapos de 17 espécies de Paepalanthus subgênero Platycaulon, sendo 10 da sect. Divisi e sete da sect. Conferti. O trabalho foi realizado para caracterizar anatomicamente os escapos. como contribuição para o entendimento do grupo, uma vez que. morfologicamente, esse é o caráter laxonômico mais importante. Procurou-se, também, confirmar ou não o reconhecimento das duas seções dentro do subgênero. Para os estudos anatômicos utilizou-se material proveniente do Brasil, obtido de exsicatas de diferentes herbários e/ou coletado na Serra do Cipó, MG. Neste trabalho observou-se que Paepalanthus subg. Platycaulon é caracterizado morfologicamente por apresentar escapos pluricapitulados no ápice. Anatomicamente, as espécies estudadas da sect. Divisi apresentam escapos com vários cilindros vasculares, na região mediana e, ainda apresentam, em Paepalanthus vellozioides e P. spixianus, feixes vasculares corticais, características únicas na família. Diferentemente, as espécies avaliadas da sect. Conferti apresentam escapos com cilindro vascular único na região mediana, padrão análogo ao das demais Eriocaulaccae, e ainda apresentam, em Paepalanthus itatiaiensis, P. planifolius e P. paulensis, feixes vasculares medulares, que até então não haviam sido referidos para a família.

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.

Macrophage activation by Paepalanthus spp. extracts

Macrófagos são conhecidos por exercerem uma importante função de mecanismo de defesa quando estas células são estimuladas com produtos naturais e produtos bacterianos (dentre outros). Uma variedade de citocinas e compostos químicos são liberados para induzir sistema de defesa fundamental. Entre outros peróxido de hidrogênio (H2O2) tem sido identificado como moléculas tendo multifunções. Entretanto está bem estabelecido que (H2O2) está envolvido em inúmeros processos fisiológicos, como por exemplo, neurotransmissão, relaxamento da musculatura lisa ou regulação imune. Para a determinação de peróxido de hidrogênio (H2O2) em macrófago peritoneal em camundongos, determinou-se a ação imunomodulatória de extratos (etanólico e etanólico 70%) obtidos de quatro espécies do gênero Paepalanthus (Eriocaulaceae) na concentração de 10 mg/mL. Os estratos etanólicos 70 % de capítulos de P. Hilairei, P. robustus, P. vellozioides e P. speciocus apresentaram maior liberação de (H2O2) do que os outros extratos etanólicos.

Quercetagetin 7-methyl ether glycosides from Paepalanthus vellozioides and Paepalanthus latipes

Several new quercetagetin 7-methyl ether glycosides were characterized from the ethanolic extracts of scapes and leaves of Paepalanthus vellozioides and P. latipes. Their structures were determined mainly by 600 MHz NMR spectroscopy. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

New naphthopyranone glycosides from Paepalanthus vellozioides and Paepalanthus latipes

Three new compounds-3,4-dihydro-10-hydroxy-7-methoxy-3-(R)-methyl-1H-3,4-dihydronaphtho-]2,3c]pyran-1-one-9-O-beta-D-glucopy ranoside (1), 3,4-dihydro-10-hydroxy-7-methoxy-3-(R)-methyl-1H-3,4-dihydronaphtho-[2,3c]-pyran-1-one-9-O-beta-D-glucopyranosyl-(1-->6)-glucopyranoside (2), and 3,4-dihydro-10-dihydroxy-7-methoxy-3-(R)-methyl-1H-3,4-dihydronaphtho-[2,3c]-pyran-1-one-9-O-beta-D-allopyranosyl (1-->6)-glucopyranoside (3)-were isolated from the leaves of Paepalanthus vellozioides and Paepalanthus latipes and characterized by spectrometric methods, mainly electrospray mass spectrometry and 1D and 2D NMR experiments. These unusual glycosylated dihydronaphthopyranones may serve as taxonomic markers of the genus Paepalanthus, since these compounds were not detected in other genera belonging to the Eriocaulaceae family.

Morpho-anatomical aspects of Paepalanthus hilairei Koern (Eriocaulaceae) from Serra do Cipo MG

The morphological characteristics of seedlings and the anatomical characteristics of vegetative organs and floral scape of P. hilairei (Eriocaulaceae) were analyzed to investigate the ecological and taxonomic implications for the species. P. hilairei is a perennial plant with an aerial stem and it grows in recently decomposed stony, sandy soils of the Serra do Cipo, in the State of Minas Gerais, Brazil. It is found both on wet and dry soils, exposed to constant winds, high light intensities and extreme daily fluctuations of temperature. The results show that the seeds have operculum and the initial seedling development stages are the same for other Eriocaulaceae. During the germination period, the undifferentiated axis of the embryo becomes apparent. The observation of the development of this axis, shows first, the growth of the leaves and later that of the adventitious root. Attention is focused on the apical stem region which presents sterelis lateral branching with adventitious roots in its base which will develop into paraclades (system of florescences). Both of them rise out of the pericycle and characterize its vegetative growth. The occurrence of a special leaf substomatal chamber may be related to an efficient protection for the gaseous exchange and may be considered an important characteristic of the Eriocaulaceae.

Embryology and seed development of Paepalanthus sect. Actinocephalus (Koern.) Ruhland (Eriocaulaceae)

The embryology and seed structure of Paepalanthus sect. Actinocephalus species were studied. The embryological and structural seed characters fit well with those of the other commelinaceous families. Within the Commelinales sensu Dahlgren, Eriocaulaceae and Xyridaceae represent two embryologically close families. In Paepalanthus sect. Actinocephalus the ovule is orthotropus, bitegmic, and tenuicellate with a micropyle formed by the inner integument. The seeds are endotestal. The outer cell layer of the testa and the outer periclinal wall of the endotesta disintegrate during development. The endotegmen is tanniniferous. The outer layer of the tegmen becomes compressed and is no longer recognizable in the mature seed. The seeds are operculate.

Xeractinol - A new flavanonol C-glucoside from Paepalanthus argenteus var. argenteus (Bongard) Hensold (Eriocaulaceae)

New compound isolated from methanolic extract from the leaves of Paepalanthus argenteus var. argenteus (Bongard) Hensold was characterized as xeractinol, a new dihydroflavonol C-glucoside. The structure was elucidated on the basis of extensive spectroscopic analysis (1D and 2D NMR, MS, HREIMS, IR and UV). Ab initio electronic structure calculations support our proposal to the molecular structure. The dihydroflavonol herein isolated may serve as taxonomic marker of Paepalanthus subgenus Xeractis, because this flavonoid have not been reported in any other taxon of Eriocaulaceae.

Naphthopyranone glycosides from Paepalanthus microphyllus

Three new naphthopyranone glycosides, paepalantine-9-O-beta -D-glucopyranosyl-(1 -->6)-beta -D-glucopyranoside (I), paepalantine-9-O-alpha -L-arabinopyranosyl-(1 -->6)-beta -D-glucopyranoside (2), and paepalantinc-9-O-alpha -L-rhamnopyranosyl-( (1 -->6)-beta -D-glucopyranoside (3), along with the known paepalantine-9-O-beta -D-glucopyranoside (4) were isolated from aerial parts of Paepalanthus microphyllus. These compounds were characterized by spectrometric methods, including electrospray mass spectrometry and 1D and 2D NMR experiments. As a part of our program for screening natural compounds for anti-HIV activity, compounds 1-4 were tested in C8166 cells infected with HIV 1(MN).

Roots, leaves and scapes anatomy of species of Paepalanthus subgenus Platycaulon (Eriocaulaceae)

The anatomical features of roots, leaves and scapes of the subgenus Platycaulon, genus Paepalanthus (Eriocaulaceae) that grow in the Brasilian rupestrian fields of Serra do Cipo - MG - Brazil were studied. The following main anatomical features were found: epidermis cells of varied thicknesses, chlorenchyma with compact or spread organization and leaf margin shape in the leaves; the scapes with continuous or discontinuous endodermis, divided or undivided pericycle, vascular bundles absent in the cortex and in the pith. These anatomical characteristics of the leaves and scapes occur in different species and can be used to separate them into Divise or Conferti sections. It was possible to confirm the proposed taxonomy based only on the morphological characteristics. Other anatomical features such as: presence or absence of air in the cortex roots and hypodermis which originate water parenchyma reserves in the mesophyll, can be an adaptative response that plants towards produce the environmental factors in this ecosystem.

Mutagenic and cytotoxic activity of an isocoumarin (Paepalantine) isolated from Paepalanthus vellozioides

A new isocoumarin with antimicrobial activity was isolated from Paepalanthus vellozioides (a native Brazilian plant) and called paepalantine. This study was carried out to assess the mutagenic activity of this new agent in assays with Salmonella typhimurium TA100, TA98, and TA102 and in Chinese hamster ovary (CHO) cell cultures, as well as cytotoxicity to McCoy cells. Paepalantine caused a significant dose-dependent increase in the frequency of revertants in the three strains used in the assay, both with and without S9 mix, in concentrations varying from 2 to 128 mu g/ plate. The mutagenicity was confirmed in assays with CHO cells treated in the G(1), S, and G(2) phases of the cell cycle. There was an increase in the chromosomal aberration frequency, mainly in the G(2) phase. Furthermore, the mitotic index of the treated cultures (40,80, and 160 mu g/ml) was significantly lower, indicating cytotoxicity. The midpoint cytotoxicity values to McCoy cells by the neutral red (NR) and microculture tetrazolium (MTT) techniques resulted in a NR50, and MTT50 of 30 and 38 mu g/ml, respectively. Alterations to the paepalantine structure are suggested to reduce its mutagenic and cytotoxic activity in investigations for its antineoplasic potential (C) 1997 Wiley-Liss, Inc.

6-methoxyquercetin-3-0-(6-E-feruloyl)-beta-D-glucopyranoside from Paepalanthus polyanthus (Eriocaulaceae)

The new 6-methoxyquercetin-3-O-(6-E-feruloyl)-beta-D-glucopyranoside (1) was isolated from the aerial parts of Paepalanthus polyanthus and characterized by spectroscopic methods, mainly 1D and 2D NMR experiments, as well as electrospray mass spectrometry. In addition four known flavonoids of taxonomic relevance were isolated and identified by comparison to literature data. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

AN ISOCOUMARIN DERIVATIVE FROM PAEPALANTHUS BROMELIOIDES

The structure of 5,7,9,10-tetramethoxy-3-methyl-1 H-naphtho[2,3-c]pyran-1-one, C18H18O6, a derivative of a natural isocoumarin isolated from Paepalanthus bromelioides, was determined by X-ray analysis, which unequivocally confirmed the previously assigned structure. Small deviations from the standard angles, resulting from steric hindrance between the methoxyl and carbonyl groups, were observed.