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.

Planifolin, a new naphthopyranone dimer and flavonoids from Paepalanthus planifolius

A new naphthopyranone dimer (I) named planifolin was isolated from a methylene chloride extract of the capitula of Paepalanthus planifolius. The structure of 1 has been determined by chemical and spectroscopic means. In addition, a known dihydronaphthopyranone glycoside and seven known flavonoids were isolated from an ethanolic extract of the leaves of P. planifolius.

Isocoumarin from Paepalanthus bromelioides

The new isocoumarin, 9,10-dihydroxy-5, 7-dimethoxy-1H-naphtho(2,3c)pyran-1-one, was isolated from the capitula of Paepalanthus bromelioides. The structure was established by means of the spectral data of the natural product and its derivatives. The natural isocoumarin isolated has strong antibiotic activity. © 1990.

Naphthopyranone glycosides from Paepalanthus bromelioides

Two new naphtho[2,3-C]pyran-1-one glycosides, paepalantine-9-O-β-D- glucopyranoside and paepalantine-9-O-β-D-allopyranosyl(1 → 6)glucopyranoside, were isolated from an ethanolic extract of capitula from Paepalanthus bromelioides and identified from their spectrometric data.

Separation of flavonoids and naphthopyrones from four Brazilian Paepalanthus species by droplet countercurrent chromatography

A general procedure was developed for the simultaneous separation of flavonoids and naphthopyrones from the polar extracts of the capitula from Brazilian everlasting plants is described. The ethanolic extracts of several species from the Paepalanthus genus (Eriocaulaceae) were fractionated by droplet countercurrent chromatography followed by column chromatography on pvp and sephadex LH-20. The isolated compounds were identified by spectrometric analysis and comparison with literature data. This approach led to the isolation of 9-O-β-D-glucopyranosylpaepalantine (1), 9-O-β-D-glucopyranosyl (1→6)allopyranosylpaepalantine (2), along with the flavonoids 6-methoxykaempferol (3), 3-O-β-D-glucopyranosyl-6-methoxykaempferol (4), patuletin (5), 3-Oβ-D-rutinosylpatuletin (6), 7-O-β-D-glucopyranosylquercetagetin (7), 5,7,4'-trihydroxy-6,3'-dimethoxyflavone (8) and 5,7,4'-trihydroxy-6,3'-dimethoxyflavonol (9).

A new cytotoxic naphthopyrone dimer from Paepalanthus bromelioides

A new naphthopyrone dimer was isolated from the capitula of Paepalanthus bromelioides by chromatographic procedures. Its structure was deduced from spectrometric data. On colorimetric assay for cytotoxicity the new dimer showed IC50 of 55.9 μM. (C) 2000 Elsevier Science B.V.

In vitro cytotoxicity of some natural and semi-synthetic isocoumarins from Paepalanthus bromelioides

Numerous natural compounds have a potential for therapeutic applications, but may have to be chemically modified to alter toxic side effects. We investigated structural parameters that could affect the cytotoxicity of isocoumarins similar to 9,10-dihydroxy-5,7-dimethoxy-1H-naphtho(2,3c)pyran-1-one (paepalantine 1). Paepalantine 1 has antimicrobial activity, as well as significant in vitro cytotoxic effects in the McCoy cell line. Two other natural and two semi-synthetic isocoumarins with similar structures obtained from the capitula of Paepalanthus bromelioides were tested on the same cell line by the neutral red assay. Substitution of the 9 and/or 10-OH group made these compounds less cytotoxic.

Characterization of flavonoids and naphthopyranones in methanol extracts of Paepalanthus chiquitensis herzog by HPLC-ESI-IT-MSn and their mutagenic activity

A HPLC-ESI-IT-MSn method, based on high-performance liquid chromatography coupled to electrospray negative ionization multistage ion trap mass spectrometry, was developed for rapid identification of 24 flavonoid and naphthopyranone compounds. The methanol extracts of the capitulae and scapes of P. chiquitensis exhibited mutagenic activity in the Salmonella/microsome assay, against strain TA97a. © 2013 by the authors.

Anatomy of scapes, bracts, and leaves of Paepalanthus sect. Diphyomene (Eriocaulaceae, Poales) and its taxonomic implications

Paepalanthus sect. Diphyomene comprises 18 species with a convoluted taxonomic history. Aiming to correlate anatomical structures with the systematics of this group and its relatives, we studied the anatomy of scapes, reproductive axis bracts, and leaves of 20 Paepalanthus species. Bracts and leaves show differences in epidermal cell thickening; mesophyll width; vascular bundle arrangement; presence or absence of a hypodermis; types of cells in the vascular bundle sheath extensions; margin shape and composition; and presence or absence of aquiferous parenchyma. Scapes differ in contour, rib number, and pith size. Some diagnostic characters found are presence of aquiferous parenchyma and absence of vascular bundle sheath extensions in leaves of P. urbanianus; vascular bundles decreasing in size towards the margin of leaves and bracts, and scapes with a triangular contour in P. flaccidus; scapes with nine ribs in P. acanthophyllus and ten in P. macer. All anatomical features are summarized in tables. These results aid in the identification and characterization of the species of P. sect. Diphyomene. They also support the current section circumscription, reinforcing the relevance of the anatomical characters in order to define natural groups. © 2012 The New York Botanical Garden.