Joel Campos De Paula

Antileishmanial sesquiterpenes from the Brazilian red alga Laurencia dendroidea.

Investigation of the bioactive crude extracts from two populations of the red alga Laurencia dendroidea from the southeastern Brazilian coast led to the identification of five sesquiterpenes: (+)-obtusane (1), a triquinane derivative (2), (-)-elatol (3), obtusol (4), and cartilagineol (5). An antileishmanial bioassay against Leishmania amazonensis was conducted for crude lipophilic extracts and for sesquiterpenes 2, 3, and 4. Compounds 3 and 4 displayed in vitro and in vivo leishmanicidal activity and very low cytotoxicity.

What are and where are the bioactive terpenoids metabolites from Dictyotaceae (Phaeophyceae)

Dictyotaceae are a rich source of secondary metabolites, especially terpenes. These natural products have been studied for their bioactivity for human and for their ecological role in nature. The present work highlights de diversity of the Dictyotaceae terpenes, emphasizing their bioactivities and the biogeography of their sources. The sesquiterpenes are found in Padina, Dictyopteris and Taonia. Although Dictyopteris and Padina can be found in all oceans, Taonia has a more restricted distribution. Diterpenes of mixed origin have been reported in Lobophora, Taonia and Stypopodium. Stypopodium is a typically tropical and warm temperate genus. Diterpenes with the spatane and seco-spatanes skeletons are known from Spatoglossum, Stoechospermum and Rugulopteryx. Spatoglossum is distributed over all the tropical marine world. Stoechospermum is known to occur in the Indian Ocean and Rugulopteryx is distributed mainly in Asia and on the Pacific Coast of Australia. The genus Dictyota contains diterpenes as the major metabolite and are present in all oceans, reaching even the cold temperate regions of northern and southern hemispheres. The terpenoids from Dictyotaceae exhibit bioactivities such as inhibition of herbivores and antifungal, cytotoxic, antibiotic, anti-inflammatory, insecticidal and antiviral activities.

Prorocentrum lima from the South Atlantic: Morphological, molecular and toxicological characterization

Morphological descriptions using light and scanning electron microscopy and molecular characterization of two Prorocentrum lima strains (UNR-01 and UNR-09) isolated from Armação dos Búzios, Rio de Janeiro, Brazil are provided. Okadaic acid (OA), dinophysistoxin-1 (DTX1) and DTX2 production by strain UNR-01 was investigated using liquid chromatography with mass spectrometry. Toxins were extracted from heat-treated (boiled) and non-boiled cell pellets to obtain respective quantities of free and total OA and DTX1. Growth parameters (growth rate and mean generation time) were determined for strain UNR-01. Prorocentrum lima cells were oblong-to-ovate in shape, broad in the middle region, and narrow at the anterior end. The periflagellar area was triangular, set into a V-shaped depression and was composed of eight periflagellar platelets of different sizes. The morphology fits well the characterization of the species isolated from elsewhere. Phylogenetic analysis based on internal transcribed spacer - ITS - and D1-D3 large subunit - LSU - of ribosomal RNA gene sequences revealed that both strains were identical and closely related to P. lima isolates from the Caribbean Sea and USA. The growth rate of strain UNR-01 was 0.24divday-1. OA concentrations were on average 15.2 and 38.5pg[OA]cell-1 for heat-treated and non-treated cells respectively, while DTX1 mean concentration was 0.5pg[DTX1]cell-1 for both heat-treated and non-treated cells. DTX2 was not detected. To date, these are the first strains of P. lima from the south Atlantic that have been characterized.

Molecular evidence of the presence of Dictyota dichotoma (Dictyotales: Phaeophyceae) in Argentina based on sequences from mtDNA and cpDNA and a discussion of its possible origin

ABSTRACT Dictyota is a brown algae genus inhabiting tropical to warm temperate environments where it is an important food source, shelter and substrate to several species of invertebrates and other algae. The taxonomy of this genus is troublesome, with poor species delimitation and doubtful records in the literature. Dictyota dichotoma, the type species of the genus, was commonly accepted as a cosmopolitan species because of the inaccurate geographical distributional range as a consequence of misidentification in several parts of the world. Recent studies with molecular data revealed new species and a new understanding of the evolution and biogeography of the genus Dictyota. These studies confined natural populations of D. dichotoma to Europe (Atlantic and Mediterranean coasts) and Macaronesian islands (Azores, Madeira and Canary archipelagos). Also, they confirmed its presence in South Africa, but whether the species was native or introduced in South Africa could not be verified. In the present study two regions of cpDNA (psbA, rbcL) and one region of mtDNA (nad1) from Argentinian samples, identified morphologically as D. dichotoma, were analysed and compared to other Dictyota species. The identity of these samples as D. dichotoma was confirmed. A haplotype network analysis using all available psbA sequences distinguished seven haplotypes divided into two geographic groups: Atlantic–Mediterranean and Canarian. In Argentina and South Africa only the most common haplotype of the Atlantic–Mediterranean group was observed. According to the paleoceanographic currents and the presence of a European haplotype, the introduced nature of D. dichotoma is indicated.