Effects of storage and solvent type in a lipophylic chemical profile of the seaweed Dictyota menstrualis

Os extratos brutos de espécimes da alga parda D. menstrualis, conhecida por produzir diterpenos como principais metabólitos secundários, foram analisados quanto ao modo de armazenamento antes da extração e tipo de solvente utilizado na obtenção do extrato bruto. Os solventes utilizados foram uma mistura diclorometano:metanol (2:1) e acetona. Os espécimes de D. menstrualis foram submetidos a três formas de armazenamento, denominados fresco, seco e congelado. Não foram observadas diferenças qualitativas nas amostras obtidas de quaisquer dos extratos brutos na análise por CG/EM, sendo compostas pelos diterpenos pachydictyol A (I), 6-hidroxi-dichotoma-3,14-dieno-1,17-dial (II), 6-hidroxi-2,7-cicloxenia-3,14-dieno-1,17-dial (III) e 6-acetoxi-dichotoma-3,14-dieno-1,17-dial (IV). Os resultados indicaram que a extração mais eficaz para os componentes de média polaridade de D. menstrualis foi obtida com o uso de acetona, que promoveu extração mais seletiva, mesmo apresentando menor rendimento em massa. Quanto à forma de armazenamento das algas, foi constatado que as metodologias não diferiram significativamente entre si, apesar da tendência de algas congeladas fornecerem o menor rendimento no total de diterpenos. Portanto, nos trabalhos envolvendo análises químicas de extratos brutos de macroalgas marinhas, a escolha do solvente de extração deve ser considerada como fator importante na varredura de substância bioativas.Crude extracts from specimens of the brown seaweed Dictyota menstrualis, known to produce diterpenes as their major secondary metabolites, were analyzed according to storage procedures before extraction, and the solvent types used to obtain the crude extracts. The specimens of D. menstrualis were submitted to three types of storage procedures, such as wet, dry, and frozen and were extracted with a mixture of dichloromethane:methanol (2:1) and acetone. Qualitative differences were not observed by GC/MS analyses of all crude extracts containing mainly the diterpenes pachydictyol A (I), 6-hydroxy-dichotoma-3,14-diene-1,17-dial (II), 6-hydroxy-2,7-cycloxenia-3,14-diene-1,17-dial (III), and 6-acetoxy-dichotoma-3,14-diene-1,17-dial (IV). The most efficient and selective extraction of the compounds with intermediate polarity produced by D. menstrualis was obtained using acetone, but with less mass production. In general, the storage procedures produced very similar results, but the frozen samples furnished low amount of total diterpenes. According to these results on chemical analysis of crude extracts of seaweeds, the choice of solvent to extraction should be considered as important aspect to better screening bioactive compounds

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

Effect of Diterpenes Isolated of the Marine Alga Canistrocarpus cervicornis against Some Toxic Effects of the Venom of the Bothrops jararaca Snake

Snake venoms are composed of a complex mixture of active proteins and peptides which induce a wide range of toxic effects. Envenomation by Bothrops jararaca venom results in hemorrhage, edema, pain, tissue necrosis and hemolysis. In this work, the effect of a mixture of two secodolastane diterpenes (linearol/isolinearol), previously isolated from the Brazilian marine brown alga, Canistrocarpus cervicornis, was evaluated against some of the toxic effects induced by B. jararaca venom. The mixture of diterpenes was dissolved in dimethylsulfoxide and incubated with venom for 30 min at room temperature, and then several in vivo (hemorrhage, edema and lethality) and in vitro (hemolysis, plasma clotting and proteolysis) assays were performed. The diterpenes inhibited hemolysis, proteolysis and hemorrhage, but failed to inhibit clotting and edema induced by B. jararaca venom. Moreover, diterpenes partially protected mice from lethality caused by B. jararaca venom. The search for natural inhibitors of B. jararaca venom in C. cervicornis algae is a relevant subject, since seaweeds are a rich and powerful source of active molecules which are as yet but poorly explored. Our results suggest that these diterpenes have the potential to be used against Bothropic envenomation accidents or to improve traditional treatments for snake bites

Effects of storage and solvent type in a lipophylic chemical profile of the seaweed Dictyota menstrualis

Crude extracts from specimens of the brown seaweed Dictyota menstrualis, known to produce diterpenes as their major secondary metabolites, were analyzed according to storage procedures before extraction, and the solvent types used to obtain the crude extracts. The specimens of D. menstrualis were submitted to three types of storage procedures, such as wet, dry, and frozen and were extracted with a mixture of dichloromethane:methanol (2:1) and acetone. Qualitative differences were not observed by GC/MS analyses of all crude extracts containing mainly the diterpenes pachydictyol A (I), 6-hydroxy-dichotoma-3,14-diene-1,17-dial (II), 6-hydroxy-2,7-cycloxenia-3,14-diene-1,17-dial (III), and 6-acetoxy-dichotoma-3,14-diene-1,17-dial (IV). The most efficient and selective extraction of the compounds with intermediate polarity produced by D. menstrualis was obtained using acetone, but with less mass production. In general, the storage procedures produced very similar results, but the frozen samples furnished low amount of total diterpenes. According to these results on chemical analysis of crude extracts of seaweeds, the choice of solvent to extraction should be considered as important aspect to better screening bioactive compounds