Dolabellane diterpenes from the Caribbean soft corals Eunicea laciniata and Eunicea asperula and determination of their anti HSV-1 activity

Dolabellane diterpenes have considerable antiviral activity, most studies have been focused towards compounds isolated from Dictyota brown algae. Although soft corals are also a significant source of these diterpenes, their antiviral potential has not been studied in detail. With the aim of assessing the biological activity of marine sources, we evaluated the dolabellane content in the soft corals Eunicea laciniata and E. asperula collected in Santa Marta, Colombian Caribbean. Dolabellanes 1-6 were isolated from E. laciniata while compounds 2, 4 and 5 were isolated from E. asperula. All compounds were identified by NMR, GC-EIMS, optical rotation and comparison with previously reported dolabellanes. GC-EIMS analyses showed that dolabellatrienone (2) transforms into compounds 4 and 5 as oxidation products upon prolonged storage; however, those compounds were also naturally present in the extract of the studied organisms. Pure dolabellanes were tested in vitro in antiviral assays against HSV-1. Compound 6 inhibited virus replication in infected cells (73.7% of inhibition at 50 μM) without cytotoxic effect (CC50 = 959), showing similar activity to the positive control Acyclovir®. Thus, compound 6 is an interesting candidate for further studies of dolabellanes as antivirals.Los dolabellanos son diterpenos con importante actividad antiviral, la mayor parte de los estudios se han realizado con compuestos aislados de algas pardas del género Dictyota. Los corales blandos son también una importante fuente de dolabellanos, pero el potencial antiviral de éstos ha sido muy poco estudiado. Como parte de nuestra búsqueda de compuestos bioactivos a partir de fuentes marinas, se llevó a cabo el estudio químico de los dolabellanos presentes en los octocorales Eunicea laciniata y Eunicea asperula, recolectados en Santa Marta, Caribe colombiano. Los dolabellanos 1-6 fueron aislados del octocoral E. laciniata mientras que en E. asperula se encontraron los compuestos 2, 4 y 5. La elucidación estructural se llevó a cabo mediante experimentos de RMN, espectrometría de masas, rotación óptica y posterior comparación con reportes previos en la literatura. El análisis por CG-EM evidenció que la dolabellatrienona (2) se puede transformar en los compuestos 4 y 5 como producto del almacenamiento prolongado, no obstante, tales compuestos también estuvieron presentes en los extractos de los organismos estudiados. El compuesto 6 inhibió la replicación del VHS-1 (73,7% de inhibición en células infectadas a una concentración de 50 μM) sin efecto citotóxico (CC50 = 959), mostrando una citotoxicidad similar al Aciclovir®, un control positivo, por lo cual se perfila como un candidato para la realización de estudios adicionales sobre el potencial de los dolabellanos como agentes antivirales

Dolabelladienols A–C, New Diterpenes Isolated from Brazilian Brown Alga Dictyota pfaffii

[Abstract:]The marine brown alga Dictyota pfaffii from Atol das Rocas, in Northeast Brazil is a rich source of dolabellane diterpene, which has the potential to be used in future antiviral drugs by inhibiting reverse transcriptase (RT) of HIV-1. Reexamination of the minor diterpene constituents yielded three new dolabellane diterpenes, (1R*,2E,4R*,7S,10S*,11S*,12R*)10,18-diacetoxy-7-hydroxy-2,8(17)-dolabelladiene (1), (1R*,2E,4R*,7R*,10S*,11S*,12R*)10,18-diacetoxy-7-hydroxy-2,8(17)-dolabelladiene (2), (1R*,2E,4R*,8E,10S*,11S,12R*)10,18-diacetoxy-7-hydroxy-2,8-dolabelladiene (3), termed dolabelladienols A–C (1–3) respectively, in addition to the known dolabellane diterpenes (4–6). The elucidation of the compounds 1–3 was assigned by 1D and 2D NMR, MS, optical rotation and molecular modeling, along with the relative configuration of compound 4 and the absolute configuration of 5 by X-ray diffraction. The potent anti-HIV-1 activities displayed by compounds 1 and 2 (IC50 = 2.9 and 4.1 μM), which were more active than even the known dolabelladienetriol 4, and the low cytotoxic activity against MT-2 lymphocyte tumor cells indicated that these compounds are promising anti-HIV-1 agents.Brasil. Conselho Nacional de Desenvolvimento Científico e Tecnológico; 490425/2010-0Brasil. Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro ; E-26/103.176/2011Ministerio de Economia y Competitividad; AGL2012-12266-C0

Evaluation of Marine Brown Algae and Sponges from Brazil as Anticoagulant and Antiplatelet Products

The ischemic disorders, in which platelet aggregation and blood coagulation are involved, represent a major cause of disability and death worldwide. The antithrombotic therapy has unsatisfactory performance and may produce side effects. So, there is a need to seek molecules with antithrombotic properties. Marine organisms produce substances with different well defined ecological functions. Moreover, some of these molecules also exhibit pharmacological properties such as antiviral, anticancer, antiophidic and anticoagulant properties. The aim of this study was to evaluate, through in vitro tests, the effect of two extracts of brown algae and ten marine sponges from Brazil on platelet aggregation and blood coagulation. Our results revealed that most of the extracts were capable of inhibiting platelet aggregation and clotting measured by plasma recalcification tests, prothrombin time, activated partial thromboplastin time, and fibrinogenolytic activity. On the other hand, five of ten species of sponges induced platelet aggregation. Thus, the marine organisms studied here may have molecules with antithrombotic properties, presenting biotechnological potential to antithrombotic therapy. Further chemical investigation should be conducted on the active species to discover useful molecules for the development of new drugs to treat clotting disorders

Dolabellanos de los octocorales caribeños Eunicea laciniata y Eunicea asperula y determinación de su actividad anti VHS-1

Los dolabellanos son diterpenos con importante actividad antiviral, la mayor parte de los estudios se han realizado con compuestos aislados de algas pardas del género Dictyota. Los corales blandos son también una importante fuente de dolabellanos, pero el potencial antiviral de éstos ha sido muy poco estudiado. Como parte de nuestra búsqueda de compuestos bioactivos a partir de fuentes marinas, se llevó a cabo el estudio químico de los dolabellanos presentes en los octocorales Eunicea laciniata y Eunicea asperula, recolectados en Santa Marta, Caribe colombiano. Los dolabellanos 1-6 fueron aislados del octocoral E. laciniata mientras que en E. asperula se encontraron los compuestos 2, 4 y 5. La elucidación estructural se llevó a cabo mediante experimentos de RMN, espectrometría de masas, rotación óptica y posterior comparación con reportes previos en la literatura. El análisis por CG-EM evidenció que la dolabellatrienona (2) se puede transformar en los compuestos 4 y 5 como producto del almacenamiento prolongado, no obstante, tales compuestos también estuvieron presentes en los extractos de los organismos estudiados. El compuesto 6 inhibió la replicación del VHS-1 (73,7% de inhibición en células infectadas a una concentración de 50 μM) sin efecto citotóxico (CC50 = 959), mostrando una citotoxicidad similar al Aciclovir®, un control positivo, por lo cual se perfila como un candidato para la realización de estudios adicionales sobre el potencial de los dolabellanos como agentes antivirales

Influence of laboratory conditions on two species Dictyotaceae family (Phaeophyceae): Diterpenoid profile and physiological response

The seaweed Dictyotaceae family has a great wealth of diterpenes with important biological activities. Information on these diterpenes qualitative and quantitative aspects in conjunction with physiological data and abiotic parameters are essential to obtain an effective algal culture system that is a sustainable resource. In this study, the diterpene profile of Dictyota menstrualis and Canistrocarpus cervicornis were analyzed as a function of in vitro maintenance time and the influence of culture medium. The algae were collected in the state of Rio de Janeiro and subjected to an acclimation period in the laboratory. Then, the species were acclimated in aquaria containing seawater from the collection sites. Then biomass algal was divided into (i) control experiment (CC): Growth in sterilized seawater; (ii) enriched experiment (EE): Growth in sterilized seawater enriched with Provasoli/2. Triplicate experiments were maintained in vitro (2.4% m/v), and the medium was changed every 7 days. Diterpenes were monitored using dichloromethane extracts from dried algae: (a) collected in the field, (b) after the acclimation period, and (c) from experimental units taken every 7 days for a total of 21 days. Among the main results, we found response variables such as specific growth rate (SGR); moreover, positive data were obtained for the alga C. cervicornis in CC, and this was evident showing after 7 days of cultivation in the experimental control unit (CU). For D. menstrualis, the SGRs for the treatments were negative at the monitored time, which was due to biomass losses, frond breakage, and rapid decomposition of some individuals that did not withstand the stress conditions during their collection. The analysis of the chemical profile by GC-MS made it possible to monitor 12 diterpenes and one sterol in the alga D. menstrualis and 7 diterpenes in C. cervicorni. The correlations found by Generalized Linear Models (GLMs) and redundancy analysis (RDA) statistical analyzes between the diterpene profile with the monitored variables (Nitrate, ammonia and pH), showed correlations for 10 diterpenes of the species D. menstrualis and 1 of the C. cervicornis, our analyses are important for the discussion of metabolic plasticity of the Dictyotaceae famil