Unravelling the structure and function of the petal appendages in the tribe Schwenckieae (Solanaceae).

The tribe Schwenckieae (Solanaceae) is characterised by the presence of appendages on the corolla, a diagnostic trait for the group. These appendages constitute a median distal projection of the three-lobed petal and occur in the genera Melananthus and Schwenckia but are absent in Heteranthia. We investigated the micromorphology and anatomical structure of the appendages and lateral petal lobes of Schwenckia americana (two varieties), S. angustifolia, S. curviflora and S. novaveneciana, and Melananthus fasciculatus. We also performed histochemical tests to determine if the appendages are involved in the production of volatiles, acting as a fragrance secretory structure (osmophore). The appendages have a uniseriate epidermis, whose cells store phenolics and lipids. The parenchyma is starch-rich just prior to anthesis in all species studied. The sensory test and anatomical analyses identified scent-secreting tissues, not only in the appendages, but also in the lateral petal lobes, whose cells are papillose with a sculptured surface. The α-naphthol p-phenylenediamine (NADI) reaction detected volatile (essential oils) compounds in S. americana var. americana and S. americana var. angustifolia. We demonstrated the secretory tissues and the production of lipids in the corolla appendages of Schwenckia and Melananthus, which indicate their osmogenic function and probable scent emission to attract pollinators.

Functional anatomy reveals secretory activity in papillose anthers of a buzz-pollinated Solanum species (Cyphomandra clade - Solanaceae).

Pollination in Solanum (Solanaceae) species is commonly performed by female bees, which vibrate anthers to extract pollen. Another pollen removal type is by male euglossine bees, milking the anthers when searching for floral scents produced by secretory tissues (osmophorous) at the swollen connective of the anthers of species in the Cyphomandra clade. Some species of this clade, however, are buzz-pollinated and present papillate anthers that should also have secretory activity, a hypothesis here tested. The anthers of Solanum luridifuscescens were fixed at different stages of development and analysed under light microscopy, SEM and TEM. Histochemical tests for the detection of starch and lipids were done. Epidermal cells of the abaxial surface of the anthers were visibly papillose, had large nuclei and dense cytoplasm rich in organelles such as mitochondria and plastids, typical features of secretory tissues. In this site, lipid droplets were detected, concomitantly with starch consumption, compatible with the secretory process in osmophores. No exudate or accumulation of substances was seen on the surface; in agreement with a previous pollination study performed in field conditions, where no pollinators were observed collecting floral scents, only pollen. The histochemical and structural analyses have evidenced the lipidic composition of the secretion, strongly pointing to terpenes as the secreted compounds. Ours findings show that papillae of the anthers have secretory activities that produce lipophilic compounds. This does not result in resources for bees, but could be an evolutionary step to the development of more specialised anthers in the Cyphomandra clade.

Antiviral activity of Bignoniaceae species occurring in the State of Minas Gerais (Brazil): part 1.

AIMS: To evaluate the antiviral activity of Bignoniaceae species occurring in the state of Minas Gerais, Brazil. METHODS AND RESULTS: Ethanol extracts of different anatomical parts of bignoniaceous plant species have been evaluated in vitro against human herpesvirus type 1 (HSV-1), vaccinia virus (VACV) and murine encephalomyocarditis virus (EMCV) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. A total of 34 extracts from 18 plant species selected according to ethnopharmacological and taxonomic criteria were screened. Fifteen of the 34 extracts (44.1%) have disclosed antiviral activity against one or more of the viruses assayed with EC(50) values in the range of 23.2 ± 2.5-422.7 ± 10.9 µg ml(-1). CONCLUSIONS: Twelve of the 34 extracts (35.3%) might be considered promising sources of antiviral natural products, as they have shown EC50 ≤ 100 µg ml(-1). The present screening discloses the high potential of the Bignoniaceae family as source of antiviral agents. SIGNIFICANCE AND IMPACT OF THE STUDY: Active extracts were identified and deserve bioguided studies for the isolation of antiviral compounds and studies on mechanism of action.

Caracterização botânica e química de Rudgea viburnoides (Cham.) Benth., (Rubiaceae) / Morphological and chemical diagnosis of Rudgea viburnoides (Cham.) Benth., (Rubiaceae)

Congonha, congonha-de-bugre e bugre são nomes populares atribuídos a várias espécies medicinais, incluindo Rudgea viburnoides (Cham.) Benth. (Rubiaceae), cujas folhas são utilizadas na medicina popular como diuréticas, hipotensoras, antireumáticas e depurativas do sangue. Esta espécie vem sendo comercializada como porangaba e utilizada em regimes de emagrecimento, substituindo Cordia ecalyculata Vell. (Boraginaceae). Neste estudo, foram determinadas as características botânicas, fisico-químicas e químicas para R. viburnoides com o objetivo de auxiliar sua identificação taxonômica e o controle de qualidade de produtos preparados com esta planta. Uma amostra referência foi coletada e submetida à caracterização macroscópica, microscópica e organoléptica, determinação de cinzas totais e umidade, prospecção fitoquímica e determinação dos perfis cromatográficos em CCD. Amostras de R. viburnoides podem ser reconhecidas pela epiderme pilosa com marcantes estrias cuticulares, estômatos paracíticos, presença de idioblastos com ráfides no mesofilo e pela configuração em arco dos tecidos vasculares da nervura de primeira ordem, caracteres ausentes em C. ecalyculata. A presença de cistólitos e canais mucilaginosos na medula diferem prontamente C. ecalyculata de R. viburnoides. A análise por CCD evidenciou a presença de flavonóides e saponinas. Amostras adquiridas no comércio e submetidas aos mesmos ensaios permitiram validar os métodos propostos e confirmaram a ampla comercialização de R. viburnoides em Minas Gerais.

Congonha, congonha-de-bugre and bugre are popular names for several medicinal plant species, including Rudgea viburnoides (Cham.) Benth. (Rubiaceae), whose leaves are widely used in popular medicine as diuretic, hypotensive, antirheumatic, and blood depurative. This species has been commercialized as porangaba, and used for diet purposes in substitution of Cordia ecalyculata Vell. (Boraginaceae). This study determines botanical, physico-chemical and chemical characteristics of R. viburnoides with the objective of providing tools for its taxonomical identification and the quality control of derived products. A reference sample was collected and submitted to macroscopical, microscopical and organoleptical characterization, total ash and water content, phytochemical screening, and TLC profile determination. Samples of Rudgea viburnoides can be easily distinguished from those of Cordia ecalyculata by the pilose epidermis with paracytic stomata, outstanding cuticularized striation, the presence of cristalliferous idioblasts, and by the arc pattern of the midvein vascular tissues. Furthermore, C. ecalyculata presents cystoliths and medullary mucilaginous channels differing from R. viburnoides. TLC analysis demostrated the presence of flavonoids and saponins. Commercially acquired samples submitted to the same assays have therefore validated the proposed methods, and confirmed the wide commercialization of R. viburnoides in the state of Minas Gerais, Brazil.

Antimalarial activity of Cinchona-like plants used to treat fever and malaria in Brazil.

For centuries, malaria was treated with the bark of Cinchona calisaya and Cinchona succirubra plants named "quinas" in Brazil, from which the quinine molecule was isolated. Other plant species known also as "quinas" are used to treat fever and malaria, like Deianira erubescens (roots and leaves), Strychnos pseudoquina (bark), and Remijia ferruginea (bark). Based on this popular knowledge, we evaluated the in vivo antimalarial activity of the ethanol crude extracts of these plant species in mice infected with Plasmodium berghei. Only Remijia ferruginea showed antimalarial activity, reducing parasitaemia and mortality at the highest dose tested. Its phytochemical analysis showed the presence of alkaloids but not quinine. The other two plant species were inactive.

Preparação e caracterização de extratos glicólicos enriquecidos em taninos a partir das cascas de Stryphnodendron adstringens (Mart. ) Coville (Barbatimão) / Preparation and characterization of propylene glicol extracts obtained from dried stem barks of Stryphnodendron adstringens (Mart. ) Coville (barbatimão)

Neste estudo, foram preparados e caracterizados extratos glicólicos de cascas de Stryphnodendron adstringens (barbatimão), visando a obtenção de extratos enriquecidos em taninos. Os extratos foram preparados, em triplicata, por meio de maceração estática da droga vegetal pulverizada, seguida de percolação, com diferentes misturas de 90 por cento (PGL90), 80 por cento (PGL80) e 70 por cento (PGL70) de propilenoglicol em água. Os extratos foram recolhidos de forma fracionada. Cada fração obtida foi submetida a análises de pH, densidade, determinação de resíduo seco, e dos teores de taninos e de polifenóis. Os resultados dessas análises demonstraram que o solvente PGL70 extraiu maior quantidade de constituintes químicos da droga vegetal, a partir das primeiras frações. No entanto, as análises revelaram que o solvente PGL80 foi mais seletivo ao extrair, especificamente, os taninos da planta. Os resultados indicaram que a incorporação de 20 por cento de água ao propilenoglicol deve conduzir a extratos mais enriquecidos em taninos, a partir das cascas de barbatimão.

Extracts from dried stem barks of Stryphnodendron adstringens (barbatimão) were prepared with 90 percent, 80 percent and 70 percent of propylene glycol and water (PGL90, PGL80 and PGL70, respectively). The extract was prepared by percolation and collected as fractions of 100mL. The pH, density, dry residue and tannin and polyphenolic contents were determined for each fraction. The results showed that the extraction of chemical compounds was more efficient with PGL70, but PGL80 was more selective for extraction of tannins, the active compounds.