Angélica Ribeiro Soares

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.

Variation in chemical defenses against herbivory in southwestern Atlantic Stypopodium zonale (Phaeophyta)

Abstract Many seaweeds produce secondary metabolites that deter herbivory, but intraspecific variation in both the identity and the concentration of chemical defenses has been documented rarely. In order to evaluate the occurrence of chemical variation in the brown seaweed Stypopodium zonale along the Brazilian coast, we investigated the defensive properties of crude extracts and major secondary metabolites found in specimens from two distant locations (Forno inlet, Búzios, southeastern Brazil and Fernando de Noronha archipelago, northeastern Brazil) against herbivory by the crab Pachygrapsus transversus and the sea urchin Lytechinus variegatus. At natural concentrations, the extracts from S. zonale from Búzios and Fernando de Noronha significantly deterred feeding by P. transversus and L. variegatus, although the former was more effective as a defense than the latter. Corroborating these results, the major metabolites atomaric acid, found in individuals from Búzios, and stypoldione, from Fernando de Noronha specimens, also inhibited herbivory, but atomaric acid was more effective as a defense against L. variegatus and P. transversus than stypoldione. The variation between S. zonale from two distant and different geographic locations in Brazil suggests that defensivechemicals from this seaweed are not qualitatively or quantitatively absolute or invariant characteristics of the species, and may represent an ecological specialization to successfully prevent herbivory.

Atividade biológica de metabólitos secundários de algas marinhas do gênero Laurencia

As algas vermelhas do genero Laurencia sao conhecidas como uma riquissima fonte de metabolitos secundarios. As principais classes quimicas ja isoladas sao terpenos - sesquiterpenos, diterpenos, triterpenos - e acetogeninas. Estudos apontam que estas substâncias apresentam importantes atividades biologicas, principalmente citotoxica e antibacteriana. Existem ainda alguns poucos trabalhos com informacoes sobre atividade antiparasitaria, antiviral e antifungica dos metabolitos de Laurencia. O forte perfil bioativo observado em alguns estudos sugere que alguns destes metabolitos podem ser futuramente utilizados como farmacos ou como prototipos de novos agentes antitumorais e antibacterianos. Muitos dos metabolitos de Laurencia ainda nao foram avaliados sob o ponto de vista farmacologico, o que representa um grande potencial a ser explorado por diversos campos da farmacologia.

Variation on diterpene production by the Brazilian alga Stypopodium zonale (Dictyotales, Phaeophyta)

Marine algae of the genus Stypopodium (Dictyotales, Phaeophyta) are distributed mainly in tropical and subtropical waters. Stypopodium zonale (Lamouroux) Papenfuss is a brown alga abundantly found along the Brazilian coast, distributed from the coast of Rio de Janeiro (Southeast, subtropical) to Ceara (Northeast Brazil, tropical). This species is known to produce several compounds which display diverse and useful biological properties (e.g. Wessels et al., 1999), although the chemistry of the Brazilian populations has never been studied. Four collections of S. zonale were made from four distinct areas of the Brazilian coast, and chemically investigated. All plants were collected from March, 1998 to July, 1999, at a depth of 5–10 m. The specimens were collected at Forno inlet (22°45 S, 41°52 W), Buzios (Rio de Janeiro State); at Atol das Rocas reef (03°51 S, 33°40 W) (Rio Grande do Norte State); at Ressurreta inlet (03°51 S, 32°25 W),

Antiviral activity of extracts from Brazilian seaweeds against herpes simplex virus

Organic extracts of 36 species of marine algae (sixteen species of Rhodophyta, eight species of Ochrophyta and twelve species of Chlorophyta) from seven locations on the Brazilian coast were evaluated for their anti-HSV-1 and anti-HSV-2 activity resistant to Acyclovir (ACV). Activity tests in crude extracts, followed by the identification of the major compounds present, were performed for all species. The chemical profiles of all crude extracts were obtained by 1H-NMR and 13C-NMR spectroscopy. The percentage of extracts with antiviral activity was higher for HSV-1 (86.1%) than for HSV-2 (55.5%). The green algae Ulva fasciata and Codium decorticatum both showed the highest activity (99.9%) against HSV-1, with triacylglycerols and fatty acids as the major components. The red alga Laurencia dendroidea showed good activity against HSV-1 (97.5%) and the halogenated sesquiterpenes obtusol and (-)-elatol were identified as the major components in the extract. Against HSV-2, the green alga Penicillus capitatus (Chlorophyta) and Stypopodium zonale (Ochrophyta) were the most active (96.0 and 95.8%). Atomaric acid, a meroditerpene, was identified as the major secondary metabolite in the S. zonale extract. These results reinforce the role of seaweeds as important sources of compounds with the potential to enter into the pipeline for development of new drugs against herpes simplex.

In Vitro Anti-HMPV Activity of Meroditerpenoids from Marine Alga Stypopodium zonale (Dictyotales)

In this paper, we evaluated the antiviral activity against HMPV replication of crude extract of the marine algae Stypopodium zonale and of two meroditerpenoids obtained from it, atomaric acid and epitaondiol, and a methyl ester derivative of atomaric acid. Their selectivity indexes were 20.78, >56.81, 49.26 and 12.82, respectively. Compared to ribavirin, the substances showed a relatively low cytotoxicity on LLC-MK2 cells, with a significant antiviral activity, inhibiting at least 90% of viral replication in vitro, which demonstrates the potential of these marine natural products to combat infections caused by HMPV in vitro.

Induction of Attachment of the Mussel Perna perna by Natural Products from the Brown Seaweed Stypopodium zonale

Marine invertebrates settle, attach, and/or metamorphose in response to signals from several sources, including seaweeds. In response to the aquaculture challenge of producing constant numbers of juveniles from cultured species, natural inducers have been screened for their ability to improve those processes. However, few chemical inducers of attachment of invertebrates have been identified, and even less of these were secondary metabolites. The goal of this work was to isolate the natural products responsible for induction activity using bioassay-guided fractionation of the organic extract of the brown seaweed Stypopodium zonale and the attachment of juveniles of the common brown mussel, Perna perna, as a model. The meroditerpene epitaondiol, identified by comparison of spectral data with the literature, promoted as much as 4.7 times more mussel attachment compared to controls at the natural concentration found in this alga (0.041% of the crude extract or 0.012% of algal dry weight). This is the first report showing that a seaweed produces terpenoid compounds as cues for invertebrate attachment, and future studies evaluating this action on settlement of mussels in the field are expected to improve aquaculture technology by increasing mussel spat production.

Antiviral activity of the green marine alga Ulva fasciata on the replication of human metapneumovirus

We evaluated the antiviral activity of the marine alga, Ulva fasciata, collected from Rasa beach and Forno beach, Búzios, Rio de Janeiro, Brazil on the replication of human metapneumovirus (HMPV). The algae extracts were prepared using three different methodologies to compare the activity of different groups of chemical composites obtained through these different methodologies. Four out of the six extracts inhibited nearly 100% of viral replication. The results demonstrated that the majority of the extracts (five out of six) possess virucidal activity and therefore have the ability to interact with the extracellular viral particles and prevent the infection. On the other hand, only two extracts (from Forno beach, obtained by maceration and maceration of the decoction) were able to interact with cell receptors, hindering the viral entry. Finally, only the extract of algae collected at Forno beach, obtained by maceration presented intracellular activity. To our knowledge, this is a pioneer study on antiviral activity of marine algae against HMPV. It is also the first on antiviral activity against HMPV ever done in Brazil. The study also shows the effect of different environment factors and different chemical procedures used to obtain the extract on its biological properties.

Sesquiterpenes from the Brazilian Red Alga Laurencia dendroidea J. Agardh

Two new chamigrane sesquiterpenes 1–2 and three known compounds 3–5 were isolated from a lipophilic extract of the red alga Laurencia dendroidea collected from the Southeastern Brazilian coast. Dendroidone (1) and dendroidiol (2) were isolated from samples collected at Biscaia Inlet, Angra dos Reis, Rio de Janeiro and at Manguinhos Beach, Serra, Espírito Santo, respectively. Debromoelatol (3), obtusane (4) and (1S*,2S*,3S*,5S*,8S*,9S*)-2,3,5,9-tetramethyltricyclo[6.3.0.01.5]undecan-2-ol (5) were obtained from specimens collected at Vermelha Beach, Parati, Rio de Janeiro. The structures of new compounds were elucidated by extensive NMR (1H-, 13C-, COSY, HSQC, HMBC and NOESY) and high resolution mass spectrometry analysis. Additionally, the absolute configuration of compound 2 was assigned by X-ray analysis. Full spectroscopic data is described for the first time for compound 3. Anti-inflammatory and antimycobacterial activities of compounds 2–5 were evaluated. Compounds 3–5 inhibited the release of inflammatory mediator NO while TNF-α levels were only affected by 3. All compounds tested displayed moderate antimycobacterial action.

Mevalonosomes: specific vacuoles containing the mevalonate pathway in Plocamium brasiliense cortical cells (Rhodophyta).

This paper has identified, for the first time in a member of the Rhodophyta, a vacuolar organelle containing enzymes that are involved in the mevalonate pathway—an important step in red algal isoprenoid biosynthesis. These organelles were named mevalonosomes (Mev) and were found in the cortical cells (CC) of Plocamium brasiliense, a marine macroalgae that synthesizes several halogenated monoterpenes. P. brasiliense specimens were submitted to a cytochemical analysis of the activity of the 3‐hydroxy‐3‐methylglutaryl‐CoA synthase (HMGS). Using transmission electron microscopy (TEM), we confirmed the presence of HMGS activity within the Mev. Because HMGS is necessary for the biosynthesis of halogenated monoterpenes, we isolated a hexanic fraction (HF) rich in halogenated monoterpenes from P. brasiliense that contained a pentachlorinated monoterpene as a major metabolite. Because terpenes are often related to chemical defense, the antifouling (AF) activity of pentachlorinated monoterpene was tested. We found that the settlement of the mussel Perna perna was reduced by HF treatment (2.25 times less than control; 40% and 90% of fouled surface, respectively; P = 0.001; F9,9 = 1.13). The HF (at 10 μg · mL−1) also inhibited three species of fouling microalgae (Chlorarachnion reptans, Cylindrotheca cloisterium, and Exanthemachrysis gayraliae), while at a higher concentration (50 μg · mL−1), it inhibited the bacteria Halomonas marina, Polaribacter irgensii, Pseudoalteromonas elyakovii, Shewanella putrefaciens, and Vibrio aestuarianus. The AF activity of P. brasiliense halogenated monoterpenes and the localization of HMGS activity inside Mev suggest that this cellular structure found in CC may play a role in thallus protection against biofouling.