Living jewels: iterative evolution of iridescent blue leaves from helicoidal cell walls.

BACKGROUND AND AIMS: Structural colour is responsible for the remarkable metallic blue colour seen in the leaves of several plants. Species belonging to only ten genera have been investigated to date, revealing four photonic structures responsible for structurally coloured leaves. One of these is the helicoidal cell wall, known to create structural colour in the leaf cells of five taxa. Here we investigate a broad selection of land plants to understand the phylogenetic distribution of this photonic structure in leaves. METHODS: We identified helicoidal structures in the leaf epidermal cells of 19 species using transmission electron microscopy. Pitch measurements of the helicoids were compared with the reflectance spectra of circularly polarized light from the cells to confirm the structure-colour relationship. RESULTS: By incorporating species examined with a polarizing filter, our results increase the number of taxa with photonic helicoidal cell walls to species belonging to at least 35 genera. These include 19 monocot genera, from the orders Asparagales (Orchidaceae) and Poales (Cyperaceae, Eriocaulaceae, Rapateaceae) and 16 fern genera, from the orders Marattiales (Marattiaceae), Schizaeales (Anemiaceae) and Polypodiales (Blechnaceae, Dryopteridaceae, Lomariopsidaceae, Polypodiaceae, Pteridaceae, Tectariaceae). CONCLUSIONS: Our investigation adds considerably to the recorded diversity of plants with structurally coloured leaves. The iterative evolution of photonic helicoidal walls has resulted in a broad phylogenetic distribution, centred on ferns and monocots. We speculate that the primary function of the helicoidal wall is to provide strength and support, so structural colour could have evolved as a potentially beneficial chance function of this structure.

Review on Compounds Isolated from Eriocaulaceae Family and Evaluation of Biological Activities by Machine Learning.

Eriocaulaceae is a pantropical family whose main center of biodiversity is in Brazil. In general, the family has about 1200 species, in which phytochemical and biological studies have shown a variety of structures and activities. The aim of this research is to compile the compounds isolated in the Eriocaulaceae family and carry out a computational study on their biological targets. The bibliographic research was carried out on six databases. Tables were built and organized according to the chemical class. In addition, a summary of the methods of isolating the compounds was also made. In the computational study were used ChEMBL platform, DRAGON 7.0, and the KNIME 4.4.0 software. Two hundred and twenty-two different compounds have been isolated in sixty-eight species, divided mainly into flavonoids and naphthopyranones, and minor compounds. The ligand-based virtual screening found promising molecules and molecules with multitarget potential, such as xanthones 194, 196, 200 and saponin 202, with xanthone 194 as the most promising. Several compounds with biological activities were isolated in the family, but the chemical profiles of many species are still unknown. The selected structures are a starting point for further studies to develop new antiparasitic and antiviral compounds based on natural products.

Floral development and vasculature in Eriocaulon (Eriocaulaceae) provide insights into the evolution of Poales.

BACKGROUND AND AIMS: Floral developmental studies are crucial for understanding the evolution of floral structures and sexual systems in angiosperms. Within the monocot order Poales, both subfamilies of Eriocaulaceae have unisexual flowers bearing unusual nectaries. Few previous studies have investigated floral development in subfamily Eriocauloideae, which includes the large, diverse and widespread genus Eriocaulon. To understand floral variation and the evolution of the androecium, gynoecium and floral nectaries of Eriocaulaceae, we analysed floral development and vasculature in Eriocaulon and compared it with that of subfamily Paepalanthoideae and the related family Xyridaceae in a phylogenetic context. METHODS: Thirteen species of Eriocaulon were studied. Developmental analysis was carried out using scanning electron microscopy, and vasculature analysis was carried out using light microscopy. Fresh material was also analysed using scanning electron microscopy with a cryo function. Character evolution was reconstructed over well-resolved phylogenies. KEY RESULTS: Perianth reductions can occur due to delayed development that can also result in loss of the vascular bundles of the median sepals. Nectariferous petal glands cease development and remain vestigial in some species. In staminate flowers, the inner stamens can emerge before the outer ones, and carpels are transformed into nectariferous carpellodes. In pistillate flowers, stamens are reduced to staminodes and the gynoecium has dorsal stigmas. CONCLUSIONS: Floral morphology is highly diverse in Eriocaulon, as a result of fusion, reduction or loss of perianth parts. The nectariferous carpellodes of staminate flowers originated first in the ancestor of Eriocaulaceae; petal glands and nectariferous branches of pistillate flowers originated independently in Eriocaulaceae through transfer of function. We present a hypothesis of floral evolution for the family, illustrating a shift from bisexuality to unisexuality and the evolution of nectaries in a complex monocot family, which can contribute to future studies on reproductive biology and floral evolution in other groups.

ABA and GA4 dynamic modulates secondary dormancy and germination in Syngonanthus verticillatus seeds.

MAIN CONCLUSION: ABA and GA metabolism during incubation rather than hormone contents in dry seeds is the key to understanding secondary dormancy and germination of Syngonanthus verticillatus seeds. The mechanism of seed dormancy cycle, although very important for preventing germination during unfavorable periods for seedling establishment, is poorly understood in tropical species. Here, we used a perennial tropical species of the Brazilian campo rupestre, Syngonanthus verticillatus (Eriocaulaceae), to investigate the involvement of ABA and GA in modulating secondary dormancy of seeds buried in situ over time and the dynamic of these hormones during the incubation of dormant and non-dormant seeds. Hormone analyses were carried out with freshly harvested seeds and on buried seeds exhumed after 3, 6 and 9 months. Dynamics of ABA and GAs in dormant and non-dormant seeds during incubation (0, 12, 24 and 36 h) under favorable conditions for germination (at 20 °C in the presence of light) were also investigated. In addition, the effects of GA4 and fluridone were evaluated for overcoming secondary dormancy. Our results showed that changes in the contents of both ABA and GA4 occurred after burial, suggesting they may be related to the modulation of secondary dormancy/germination of S. verticillatus seeds. The application of fluridone was more effective than GA4 at overcoming secondary dormancy. We conclude that during incubation, de novo ABA synthesis and its consequent maintenance at high contents regulate the inhibition of germination in dormant seeds, while GA4 synthesis and ABA catabolism modulate the germination of non-dormant seeds. ABA and GA metabolism during incubation of both dormant and non-dormant seeds rather than hormone contents of dry seeds in the field is thought to be the key to understanding secondary dormancy and germination.

First molecular phylogenetic insights into the evolution of Eriocaulon (Eriocaulaceae, Poales).

Eriocaulon is a genus of c. 470 aquatic and wetland species of the monocot plant family Eriocaulaceae. It is widely distributed in Africa, Asia and America, with centres of species richness in the tropics. Most species of Eriocaulon grow in wetlands although some inhabit shallow rivers and streams with an apparent adaptive morphology of elongated submerged stems. In a previous molecular phylogenetic hypothesis, Eriocaulon was recovered as sister of the African endemic genus Mesanthemum. Several regional infrageneric classifications have been proposed for Eriocaulon. This study aims to critically assess the existing infrageneric classifications through phylogenetic reconstruction of infrageneric relationships, based on DNA sequence data of four chloroplast markers and one nuclear marker. There is little congruence between our molecular results and previous morphology-based infrageneric classifications. However, some similarities can be found, including Fyson's sect. Leucantherae and Zhang's sect. Apoda. Further phylogenetic studies, particularly focusing on less well sampled regions such as the Neotropics, will help provide a more global overview of the relationships in Eriocaulon and may enable suggesting the first global infrageneric classification.

Inflorescences in Eriocaulaceae: taxonomic relevance and practical implications.

BACKGROUND AND AIMS: Inflorescences are thought to be of enormous taxonomic relevance; however, at the same time they are regarded as being notoriously difficult. This is partly due to the conflicting needs of floristics and evolutionary botany, but partly also due to the complicated and confusing terminology introduced by W. Troll and his school. METHODS: The branching patterns of representatives of the genera Eriocaulon, Syngonanthus and Paepalanthus have been studied in the field and from preserved material by scanning electron microscopy. Branching patterns and formation sequences have been analysed and documented in longitudinal schemes and diagrams. Repetitive units of different levels are detected and related to the body plans of other species of the family. KEY RESULTS: The repetition of very few different branching patterns on different levels of complexity may lead to highly complex inflorescences. However, terms are needed only for patterns; levels may be numbered consecutively. While complex inflorescences are often described as additions or aggregations of units, there is some evidence that complex inflorescences are often the result of fractionation of inflorescence meristems. CONCLUSIONS: Precise descriptions of inflorescences useful for diagnostics and phylogenetics can be much simpler than they often are today. If complex inflorescences are the result of meristem fractionation, intermediate morphotypes cannot be expected. On the other hand, such intermediate morphotypes should occur if a complex inflorescence is formed following an aggregation pathway. Unless the repetitive patterns shown here are not correlated to complementary gene activities the inflorescences are not fully understood.

Three new feruloyl glucuronopyranosyl glycerols from Eriocaulon buergerianum with their anti-fibrotic effects on hepatic stellate cells.

Three new feruloyl glucuronopyranosyl glycerols, 1-O-α-D-(2'-feruloyl) glucuronopyranosyl glycerol (1), 1-O-α-D-(3'-feruloyl) glucuronopyranosyl glycerol (2), and 1-O-α-D-(4'-feruloyl) glucuronopyranosyl glycerol (3) were isolated and purified from the capitulum of Eriocaulon buergerianum Koern. Their structures were identified by spectroscopic and chemical methods. Molecular docking study showed that 1 is a potential inhibitor of TGF-ß1 receptor. Bioassay results revealed that 1 exhibited strong inhibitory activity against the TGF-ß-induced expression of α-smooth muscle actin (α-SMA) and fibronectin in human hepatic stellate LX-2 cells. The results in this study indicated that the new feruloyl glucuronopyranosyl glycerol 1 has preventive and therapeutic potentials against hepatic fibrosis.

Yeast in plant phytotelmata: Is there a "core" community in different localities of rupestrian savannas of Brazil?

Ephemeral microbial communities usually undergo priority effect and result in higher diversity with a few representatives of each species. Community structure of yeasts in bromeliad tanks was compared between two rupestrian savanna (Cerrado) areas in Brazil and to yeasts isolated from water holes in the same areas. Water samples were collected from 60 tanks of bromeliads Bromelia karatas and Encholirium sp. and rock holes at the Karstic Area of Aurora, Tocantins State and 60 tanks of Vriesea minarum (Bromeliaceae) and Paepalanthus bromelioides (Eriocaulaceae) at Serra do Cipó National Park, Minas Gerais State in Brazil. The yeast diversity comprised 90 species from which 60% are basidiomycetous yeasts usually associated with phylloplane, soils, and aquatic habitats. The species Papiliotrema laurentii, Rhodotorula mucilaginosa, Pa. nemorosus, and Pseudozyma hubeiensis were the most frequent species associated with bromeliads. Eighteen yeast species, two ascomycetous and 16 basidiomycetous, were consistently isolated from the substrates in both areas and may represent a core community in bromeliads in rupestrian fields. Singlets occurred in 38 to 69% of samples, and 32 species were isolated only once. Our findings reinforce the ephemeral nature of the yeast communities associated with tank-forming plants in which individual phytotelmata act as patches or aquatic islands prone to rapid colonization-extinction rates receiving inocula from plant and soil debris. Ephemeral rock holes also represent a transitory habitat for yeast species associated with plants and soil.

The complete chloroplast genome sequence of Eriocaulon nepalense (Eriocaulaceae).

The complete chloroplast (cp) genome sequence of Eriocaulon nepalense was sequenced and assembled in this study. The cp genome of E. nepalense is 150947 bp in length, composed of a pair of 26451 bp inverted repeat regions (IRs), separated by a large single-copy region (LSC) of 81064 bp, and a small single-copy region (SSC) of 16981 bp. The cp genome contained 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and 4 ribosomal RNA genes. The phylogenetic position of E. nepalense based on the cp genome data is closer to E. decemflorum than E. buergerianum.

Characterization of the complete chloroplast genome of a common Chinese medicinal herb, Eriocaulon buergerianum (Eriocaulaceae: Eriocaulon).

Eriocaulon buergerianum is a common Chinese medicinal herb and belongs to the family Eriocaulaceae genus Eriocaulon the annual herbs. In this study, the complete chloroplast genome of E. buergerianum was assembled and reported. The complete chloroplast genome of E. buergerianum is 157,016 bp in length as the circular, which harbours a large single-copy region (LSC) of 81,534 bp, a small single-copy region (SSC) of 17,114 bp, and two inverted-repeat regions (IRs) of 26,393 bp each one. The overall nucleotide content of the chloroplast genome: A of 31.8%, T of 32.4%, C of 18.2% G of 17.6%, and 35.8% GC content. The chloroplast genome of E. buergerianum contains 133 genes, which includes 88 protein-coding genes (PCGs), 37 transfer RNA (tRNAs), and 8 ribosome RNA (rRNAs). The evolutionary analysis used neighbour-joining (NJ) method and the result showed that E. buergerianum was closely related to Eriocaulon sexangulare in the family Eriocaulaceae. This study will be helpful for genome data and genomic resources of the family Eriocaulaceae for further.

Gastroprotective effects (in rodents) of a flavonoid rich fraction obtained from Syngonanthus macrolepsis.

OBJECTIVES: Syngonanthus macrolepis, popularly known in Brazil as 'sempre-vivas', is a plant from the family Eriocaulaceae, it is found in the states of Minas Gerais and Bahia. The species contains a variety of constituents, including flavonoids with gastroprotective effect. In this work, a flavonoid-rich fraction (Sm-FRF) obtained from scapes of S. macrolepis was investigated for preventing gastric ulceration in mice and rats. METHODS: The activity was evaluated in models of induced gastric ulcer (absolute ethanol, stress, non-steroidal anti-inflammatory drugs and pylorus ligation). The cytoprotective mechanisms of the Sm-FRF in relation to sulfhydryl (SH) groups, nitric oxide (NO) and antioxidant enzymes were also evaluated. KEY FINDINGS: The Sm-FRF (100 mg/kg, p.o.) significantly reduced gastric injury in all models, and did not alter gastric juice parameters after pylorus ligation. CONCLUSIONS: The results indicate significant gastroprotective activity for the Sm-FRF, which probably involves the participation of both SH groups and the antioxidant system. Both are integral parts of the gastrointestinal mucosa's cytoprotective mechanisms against aggressive factors.

Estrogenic and chemopreventive activities of xanthones and flavones of Syngonanthus (Eriocaulaceae).

The possible benefits of some bioactive flavones and xanthones present in plants of the genus Syngonanthus prompted us to screen them for estrogenic activity. However, scientific research has shown that such substances may have undesirable properties, such as mutagenicity, carcinogenicity and toxicity, which restrict their use as therapeutic agents. Hence, the aim of this study was to assess the estrogenicity and mutagenic and antimutagenic properties. We used recombinant yeast assay (RYA), with the strain BY4741 of Saccharomyces cerevisiae, and Ames test, with strains TA100, TA98, TA97a and TA102 of Salmonella typhimirium, to evaluate estrogenicity, mutagenicity and antimutagenicity of methanolic extracts of Syngonanthus dealbatus (S.d.), Syngonanthus macrolepsis (S.m.), Syngonanthus nitens (S.n.) and Syngonanthus suberosus (S.s.), and of 9 compounds isolated from them (1=luteolin, 2=mix of A-1,3,6-trihydroxy-2-methoxyxanthone and B-1,3,6-trihydroxy-2,5-dimethoxyxanthone, 3=1,5,7-trihydroxy-3,6-dimethoxyxanthone, 4=1,3,6,8-tetrahydroxy-2,5-dimethoxyxanthone, 5=1,3,6,8-tetrahydroxy-5-methoxyxanthone, 6=7-methoxyluteolin-8-C-ß-glucopyranoside, 7=7-methoxyluteolin-6-C-ß-glucopyranoside, 8=7,3'-dimethoxyluteolin-6-C-ß-glucopyranoside and 9=6-hydroxyluteolin). The results indicated the estrogenic potential of the S. nitens methanol extract and four of its isolated xanthones, which exhibited, respectively, 14.74±1.63 nM; 19.54±6.61; 7.20±0.37; 6.71±1.02 e 10.01±4.26 nM of estradiol-equivalents (EEQ). None of the extracts or isolated compounds showed mutagenicity in any of the test strains and all of them showed antimutagenic potential, in particular preventing mutations caused by aflatoxin B1 (AFB1) and benzo[a]pyrene (B[a]P). The results show that the xanthones, only isolated from the methanol extract of S. nitens capitula, probably were the responsible for its estrogenic activity and could be useful as phytoestrogens, providing a new opportunity to develop hormonal agents. In addition, flavones and xanthones could also be used as a new antimutagenic agent. Since, the mutagens are involved in the initiation and promotion of several human diseases, including cancer, the significance of novel bioactive phytocompounds in counteracting these pro-mutagenic and carcinogenic effects is now gaining credence.

Eriocaulon madayiparense (Eriocaulaceae) - A new species from the foot hills of the Western Ghats of India.

Eriocaulon madayiparense Swapna, Rajesh, Manju & Prakashkumar, sp. nov. is described and illustrated from the Madayipara, a lateritic hillock in the midland of Kannur District of Kerala. The species is allied to Eriocaulon eurypeplon Koernicke, in its two free male and female sepals, female sepals being keeled and acute and not exceeding the floral bracts, acuminate leaf apex and setiform seed appendages appearing in vertical rows, but differs mainly in having yellow seeds with solitary appendage arising from transverse radial walls, curved and connate with the adjacent ones of the same vertical row forming longitudinal parallel ribs on the surface of the seeds.

In vitro establishment of Comanthera curralensis , "sempre viva" native of Chapada Diamantina - Bahia / Estabelecimento in vitro de Comanthera curralensis, "sempre viva", nativa da Chapada Diamantina - Bahia

ABSTRACT: The goal of the present study was to evaluate the germination, initial growth, and in vitro co-cultivation of Comanthera curralensis Moldenke, a "sempre viva" native of the Chapada Diamantina state of Bahia. Full strength (MS) and half-strength MS (MS1/2) growth media supplemented with two different sucrose concentrations (15 and 30g L-1) were tested for germination and initial plant growth. Three different plant densities were tested by in vitro culture (8, 10 and 12 plants per container). MS1/2 medium with 15g L-1 sucrose resulted in a higher percentage of germination and plant growth for the in vitro establishment of C. curralensis. The use of 12 plants per container is indicated for cost reduction in C. curralensis in vitro production.

RESUMO: Este trabalho teve como objetivo avaliar a germinação, o crescimento inicial e o co-cultivo in vitro de Comanthera curralensis Moldenke, uma "sempre viva" nativa da Chapada Diamantina-BA. Para germinação e crescimento inicial, foram testados os meios de cultura MS completo e MS1/2 suplementados com duas concentrações de sacarose (15 e 30gL-1); no cultivo in vitro, foram testadas três quantidades de plantas por recipiente (8,10 e 12). A utilização do meio MS1/2 com 15gL-1 de sacarose proporcionou maiores porcentagem de germinação crescimento das plantas no estabelecimento in vitro de C. curralensis , e o uso de 12 plantas por recipiente é indicado para a redução de custos na produção in vitro da espécie.

Morfología de semillas y desarrollo post-seminal de especies de Comanthera (Eriocaulaceae)

Comanthera brasiliana, C. magnifica y C. suberosa (Eriocaulaceae) forman parte de la lista de especies amenazadas de extinción en Brasil, debido a su alto grado de endemismo y a la recolecta indiscriminada. Estas tres especies junto con C. brunnea y C. linearis constituyen el clado de Comanthera magnifica. Se estudió la germinación, la morfología de semillas y el desarrollo post-seminal de las cinco especies, buscando caracterizar morfológica y anatómicamente las semillas y estadios posteriores a la germinación, así como generar datos que ayuden en la conservación de estas especies. Se recolectaron semillas maduras en los "campos rupestres" de Minas Gerais, Brasil. Fueron puestas a germinar cuatro repeticiones de 15 semillas para cada especie en cajas de Petri con papel filtro humedecido con agua destilada, a 25 °C y luz fluorescente. Para el estudio morfológico de las semillas fue usado microscopía electrónica de barrido. Para la anatomía del desarrollo post-seminal, cada estado del desarrollo fue incluido en historresina, cortado con un micrótomo rotativo y analizado con microscopía de luz. Forma y tamaño de las semillas, así como las estructuras de la cubierta seminal permiten diferenciar las especies; a partir de estos caracteres desarrollamos una clave de identificación. Las semillas germinan en altos porcentajes (> 90 %) y rápidamente (< 7 días). La germinación ocurre a través de la protrusión del eje embrionario. Aproximadamente cuatro días después de germinar aparece la primera hoja, seguida por la raíz adventicia; después de 10-15 días se desarrollan la segunda hoja y nuevas raíces adventicias. En condiciones naturales estas especies habitan en suelos derivados de cuarcita y poseen semillas diminutas (tipo polvo) que germinan y se desarrollan rápidamente, incluso más rápido que en otras Eriocaulaceae de suelos mésicos. Estos datos pueden ayudar en la obtención de plántulas de las especies estudiadas, contribuyendo en la conservación de las mismas.

Comanthera brasiliana, C. magnifica and C. suberosa (Eriocaulaceae) are included in the Brazilian list of endangered species, due to intensive harvest and micro-endemism. These species form the clade of Comanthera magnifica, along with C. brunnea and C. linearis. Germination, seed morphology and post-seminal development were studied aiming to characterize all five species and to provide information for their conservation. Seeds were collected in "campos rupestres" of Minas Gerais, Brazil. Seed morphology was examined using scanning electron microscope. For germination tests, mature seeds were placed in Petri dishes lined with filter paper dampened with distilled water at 25 °C and fluorescent light; four repetitions with 15 seeds were performed for each species. For the anatomical analysis of post-seminal development, seedlings at different developmental stages were included in historesin, cut with a rotatory microtome and examined under a light microscope. The structure of the seed coat and the shape and size of the seeds were characteristics that allowed species differentiation, and based on the seeds morphological characteristics, an identification key is provided. The seed germination was high (> 90 %) and fast (< 7 days). Germination occured through the axis protrusion of the embryo. Approximately four days after germination, the first leaf develops and is followed by the adventitious roots. After 10-15 days, the second leaf and the new adventitious roots develop. In field conditions, the studied species occur in quartzite soils and their small seeds (dust-like type) germinate faster than the other Eriocaulaceae species (from mesic soils). These results provide reliable information that may contribute to the species management and conservation.

Body size and clonality consequences for sexual reproduction in a perennial herb of Brazilian rupestrian grasslands / Consequências do tamanho de corpo e da clonalidade para a reprodução sexuada de uma herbácea perene doa campos rupestres brasileiros

Body size is one of the most important factors regarding herbaceous perennial plants life-histories, and several fitness components of these organisms are related to size. Clonal plants show distinct kinds of reproduction and can develop offspring by sexual or asexual ways. We aimed to understand how body size affects Comanthera nivea (Eriocaulaceae) sexual reproduction and to verify how clonal growth is related to flower head production in this species. We sampled 600 rosettes in rupestrian grasslands and performed linear regression analysis between body size and number of produced flower heads. We also compared the flower head production between isolated rosettes and rosettes within clones. Our results showed that body size was significantly related, but explained only a small part of flower head production. The flower head production was higher in rosettes within clones than in isolated ones. The clones presented a rosette or a small group of rosettes that concentrated the sexual reproduction. Clonality was positively associated with sexual reproduction. Clonality can represent an important way of allowing the persistence of plants by sexual reproduction in markedly seasonal stressful environments. The cases of clonality enhancing the sexual reproduction must be considered and put in focus on reproductive biology research.

O tamanho de corpo é um dos atributos de história de vida mais importantes para plantas herbáceas perenes e muitos componentes da aptidão desses organismos são relacionados ao tamanho. As plantas clonais apresentam diferentes tipos de reprodução e podem gerar prole por vias sexuadas ou assexuadas. Nosso objetivo foi compreender como o tamanho de corpo afeta a reprodução sexual em Comanthera nivea e verificar como o crescimento clonal relaciona-se à produção de capítulos dessa espécie. Nós amostramos 600 rosetas em campos rupestres e utilizamos regressões lineares para verificar a relação entre o tamanho de corpo e o número de capítulos produzidos pela planta. Nós também comparamos a produção de capítulos entre rosetas isoladas e rosetas pertencentes a clones. Nossos resultados mostram que o tamanho de corpo tem influência positiva significativa na produção de capítulos, mas explica apenas parte da variação nos dados. A produção de capítulos é maior em rosetas pertencentes a clones que em rosetas isoladas. Os clones geralmente apresentam uma roseta, ou um grupo de rosetas, que concentra a reprodução sexual. A clonalidade apresentou ligações significativas com a reprodução sexuada. Em ambientes sazonais a clonalidade pode representar uma importante forma de persistência das plantas já que pode permitir um melhor desempenho da reprodução sexuada em vista dos estresses ambientais. Os casos nos quais a clonalidade representa uma via de melhor desempenho para a reprodução sexuada devem ser considerados e colocados em foco na pesquisa em biologia reprodutiva.

Atividade antioxidante de xantonas isoladas de espécies de Leiothrix (Eriocaulaceae) / Antioxidant effects of xanthones isolated from Leiothrix species (Eriocaulaceae)

Leiothrix (Eriocaulaceae) é um gênero exclusivo da América do Sul, com 37 espécies restritas ao Brasil. Leiothrix flavescens (Bong.) Ruhland e Leiothrix curvifolia (Bong.) Ruhland, são espécies endêmicas em áreas dos Estados de Minas Gerais e Bahia. Existem na literatura poucos estudos químicos e biológicos realizados com espécies desse gênero. Neste trabalho, foi estudada a atividade antioxidante pelo ensaio TEAC (Trolox Equivalent Antioxidant Capacity) e de autoxidação, utilizando ácido linoléico, de xantonas isoladas dos extratos etanólicos de L. curvifolia e L. flavescens. As substâncias apresentaram moderada atividade antioxidante, quando comparadas com padrões de quercetina e de BHT (2, 6 - ditercbutil - 4 - metóxifenil).

Leiothrix (Eriocaulaceae) is an exclusively South American genus of which 37 species are restricted to Brazil. Leiothrix flavescens (Bong.) Ruhland and Leiothrix curvifolia (Bong.) Ruhland, are species endemic to areas of Minas Gerais and Bahia States. Chemical and biological investigations of this genus are scarse. The objective of this work was to investigate the antioxidant effect using TEAC and linoleic acid assays of the xanthones isolated from the ethanolic extract of these species. These substances showed a moderate antioxidant activity when compared to quercetin and to BHT.

Avaliação da atividade mutagênica do extrato etanólico bruto de Paepalanthus latipes (Eriocaulaceae) e dos compostos flavonoídicos 7-metoxilados relacionados / Mutagenicity evaluation of crude ethanolic extract of Paepalanthus latipes (Eriocaulaceae) and isolated 7-methoxyflavonoids

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.

Paepalanthus latipes (Silveira) is one of the native Brazilian plants from Serra do Cipó, Minas Gerais, known as "sempre-vivas" which is exported to the United States, Europe and Japan because of its ornamental value. Few results were reported in relation to the biological activity of these plants. In this work, the mutagenicity of the crude ethanolic extract of P. latipes and isolated 7-methoxyflavonoids (7-methylquercetagetin and 7-methylquercetagetin-4'-O-β-D-glucopyranoside) was evaluated by using the Ames test with Salmonella typhimurium TA98 and TA100 strains, at concentrations from 62.5 to 375 μg/plate, with and without metabolic activation (using microsomal S9 fraction). Results demonstrated that both the extract of P. latipes as well as the tested 7-methoxyflavonoids did not induce mutagenicity at the experimental tested conditions.

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 por cento) obtidos de quatro espécies do gênero Paepalanthus (Eriocaulaceae) na concentração de 10 mg/mL. Os estratos etanólicos 70 por cento de capítulos de P. Hilairei, P. robustus, P. vellozioides e P. speciocus apresentaram maior liberação de (H2O2) do que os outros extratos etanólicos.

Macrophages are known to play an important role in host defense mechanisms when these cells are stimulated with natural and bacterial products (and others). A variety of cytokines and chemicals compounds are released to induce fundamental defense system. Among them hydrogen peroxide (H2O2) has been identified as molecules having multi-functions. Moreover it has been established that H2O2 is involved is a number physiological processes, e.g., neurotransmission, smooth muscle relaxation or immune regulation. By the determination of hydrogen peroxide (H2O2) in peritoneal macrophage cultures of mice, we determined the immunomodulatory action of two extracts (ethanolic and 70 percent ethanolic) obtained of the four species to the Paepalanthus genus (Eriocaulaceae) in the concentration of 10 mg/mL. The 70 percent ethanolic extracts from capitula of P. hilairei, P. robustus, P. vellozioides . and P. speciosus presented higher liberation of H2O2 than the ethanolic extracts.