Maria Christina dos Santos Verdam

Phytochemical constituents and preliminary toxicity evaluation of leaves from Rourea induta Planch. (Connaraceae)

Most active plants are toxic at high doses and it is therefore important to investigate the preliminary toxicity of plant extracts. The Rourea induta species is a potential drug with no phytochemical or biological studies registered in the literature. Thus, a phytochemical study and a toxicity analysis of the ethanolic extract obtained from the leaves of Rourea induta Planch., Connaraceae, was run. A long chain hydrocarbon, n-tetracosane, and four flavonoids were identified: quercetin, and three glycosylated derivates, quercetin-3-O-α-arabinofuranoside, quercetin-3-O-β-xyloside and quercetin-3-O-β-galactoside. This is the first time these have been isolated in this species. The structures were elucidated by 13C NMR, 1H NMR, UV and IR spectroscopy. The toxicity evaluation of extracts was performed by the brine shrimp method and determination of hemolytic activity. The samples demonstrated no toxic potential by the analyzed methods.

Avaliação do potencial antioxidante frente à oxidação lipídica e da toxicidade preliminar do extrato e frações obtidas das frondes de Dicksonia sellowiana (Presl.) Hook

The species Dicksonia sellowiana, popularly known as tree fern, are a natural fern from American continent found in the Atlantic Forest in Brazil. In 2001 it was added to the list of IBAMA as endangered species due to its exploitation for pots craft for gardening species. This paper describes the antioxidant lipid potential (TBARS and System β-carotene / linoleic acid) of the crude extract and fractions obtained by Soxhlet apparatus of Dicksonia sellowianafronds, besides the cytotoxic and hemolytic activity in vitro. By the TBARS method, all samples tested showed activity, particularly the fraction ethyl acetate and the crude extract whose activity was comparable to standard ascorbic acid. In the system β-carotene / linoleic acid, the fraction of ethyl acetate and crude extract inhibited the oxidation of linoleic acid, especially the ethyl acetate fraction which did not differ statistically from the standard BHT. In a preliminary assessment of toxicity,cytotoxic and hemolytic activity of crude extracts and fractions in the tested models were not observed. The results of this study indicate the antioxidant potential of this plant species in models of inhibiting lipid oxidation without producing toxicity.

Atividade antioxidante e toxicidade preliminar do extrato e frações obtidas das folhas e cascas do caule de Dasyphyllum tomentosum (Spreng.) Cabrera

ABSTRACT: Antioxidant activity and preliminary toxicity of the extracts and fractions obtained from the leaves and stem bark of Dasyphyllum tomentosum (Spreng.) Cabrera. Dasyphyllum tomentosum (Spreng.) Cabrera, which belongs to the Asteraceae family, is well known for having many species with therapeutic properties. The aim of this study was to evaluate the extracts and fractions from the leaves and stem bark of D. tomentosum with respect to the antioxidant, cytotoxic and hemolytic activity in in vitro tests. All samples showed antioxidant activity by the DPPH inhibition method, especially the ethyl acetate fraction obtained from the leaves, whose activity was comparable to that of standard ascorbic acid and rutin. Regarding the reduction of the phosphomolybdenum complex, we noted that this same fraction was only similar to rutin and the fraction obtained from the stem bark showed superior results. There was no cytotoxicity and hemolytic activity compared to the models used in the extracts and fractions. The results demonstrate the antioxidant potential of the species without showing toxicity.

Morphology and anatomy of Justicia acuminatissima leaves

Justicia acuminatissima (Miq.) Bremek., Acanthaceae, is a subshrub found in northern Brazil, where it is widely used by the population of this region as an anti-inflammatory medicine. Despite this popular use, there is no pharmacognostical data to support the correct identification of this species. We therefore performed a morpho-anatomical, histochemical and phytochemical analysis of the leaves of this species, using well-known methods. The leaves are simple, exstipulate, green on the surfaces, and pubescent, with a lanceolate shape, crenate margin, pinnate venation and decussate phyllotaxy. The parenchyma is palisade and spongy, and its vascular system is bilateral. Glandular and non-glandular trichome and cystoliths were also detected. There are diacytic stomata on both the adaxial and abaxial surfaces of epidermis. Histochemical tests revealed the presence of phenolic compounds, amide and protein. Phytochemical tests showed the presence of coumarins, tannins, catechins, saponins and steroids.