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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.

Marine organisms are rich sources of natural products that, among other activities, help to maintain the species equilibrium. Samples of the marine brown alga Canistrocarpus cervicornis (Kützing) De Paula & De Clerck were collected in Búzios, Rio de Janeiro, Brazil, in June 2006. The extract was obtained in CH2Cl2 and subjected to fractionation by chromatographic methods in order to isolate and purify the compound (4R, 7R, 14S)-4α, 7α-diacethoxy-14-hydroxydolastane-1(15), 8-dien. Then, the effects of the extract and the dolastane diterpene on zygotes and gametes of the sea urchin Lytechinus variegatus were evaluated. The exposure of male and female gametes to the C. cervicornis extract promoted, respectively, a reduction of 10-30% in fertilization and a 20 to 70% decrease in the number of eggs. Furthermore, the exposure of zygotes to the extract inhibited their development up to 86.7 ± 1.6% (at a concentration of 250 µg mL-1), as well as generating abnormalities in 39-50% of zygotes. The results of the dolastane diterpene showed no evidence of inhibition in the zygotes' development, thought it was proved to induce anomalies. At higher concentrations (25 and 50 µg mL-1), it was possible to observe cell lyses.

Marine organisms are rich sources of natural products that, among other activities, help to maintain the species equilibrium. Samples of the marine brown alga Canistrocarpus cervicornis (Kützing) De Paula & De Clerck were collected in Búzios, Rio de Janeiro, Brazil, in June 2006. The extract was obtained in CH2Cl2 and subjected to fractionation by chromatographic methods in order to isolate and purify the compound (4R, 7R, 14S)-4α, 7α-diacethoxy-14-hydroxydolastane-1(15), 8-dien. Then, the effects of the extract and the dolastane diterpene on zygotes and gametes of the sea urchin Lytechinus variegatus were evaluated. The exposure of male and female gametes to the C. cervicornis extract promoted, respectively, a reduction of 10-30% in fertilization and a 20 to 70% decrease in the number of eggs. Furthermore, the exposure of zygotes to the extract inhibited their development up to 86.7 ± 1.6% (at a concentration of 250 µg mL-1), as well as generating abnormalities in 39-50% of zygotes. The results of the dolastane diterpene showed no evidence of inhibition in the zygotes’ development, thought it was proved to induce anomalies. At higher concentrations (25 and 50 µg mL-1), it was possible to observe cell lyses.

Los organismos marinos son fuentes ricas en productos naturales que, entre otras actividades, ayudan a mantener el equilibrio entre las especies. Se colectaron muestras de Canistrocarpus cervicornis (Kützing) De Paula & De Clerck en Armação de Buzios, Estado de Rio de Janeiro, Brasil, durante junio de 2006 y se sometieron a extracción en C[H.sub.2][Cl.sub.2] hasta obtener un extracto bruto. Mediante técnicas tradicionales de fitoquímica se aisló y purificó el producto natural mayoritario dolastano (4R, 7R, 14S)-4α, 7α- diacetoxi-14hidroxidolasta-1(15),8-dieno. Posteriormente, se evaluaron los efectos en diferentes concentraciones del extracto bruto en gametos y del extracto bruto y dolastano en cigotos del erizo de mar Lytechinus variegatus. Los resultados sugieren que cuando los gametos son expuestos al extracto bruto se promueve una disminución en las tasas de fecundación, 10 a 30% (espermatozoides) y de 20 a 70% (óvulos). Además, cuando los cigotos fueron expuestos al extracto bruto se inhibió el desarrollo en un 86,7% [+ ó -]1,6 (250 [micrón]g [mL.sup.-1]) y se generaron cigotos anormales que variaron entre 39 y 50%. Los resultados de los experimentos con el dolastano no mostraron evidencias de inhibición del desarrollo embrionario. Sin embargo, se constató la inducción de anomalías y en las mayores concentraciones (25 y 50 [micrón]g [mL.sup.-1]) se registró el evento de lisis en los cigotos. Palabras clave: productos naturales, dolastanos, algas pardas, diterpenos, Lytechinus variegatus, Brasil. Marine organisms are rich sources of natural products that, among other activities, help to maintain the species equilibrium. Samples of the marine brown alga Canistrocarpus cervicornis (Kützing) De Paula & De Clerck were collected in Búzios, Rio de Janeiro, Brazil, in June 2006. The extract was obtained in C[H.sub.2][Cl.sub.2] and subjected to fractionation by chromatographic methods in order to isolate and purify the compound (4R, 7R, 14S)-4α, 7α-diacethoxy-14-hydroxydolastane-1(15), 8-dien. Then, the effects of the extract and the dolastane diterpene on zygotes and gametes of the sea urchin Lytechinus variegatus were evaluated. The exposure of male and female gametes to the C. cervicornis extract promoted, respectively, a reduction of 10-30% in fertilization and a 20 to 70% decrease in the number of eggs. Furthermore, the exposure of zygotes to the extract inhibited their development up to 86.7 ± 1.6% (at a concentration of 250 µg [mL.sup.-1]), as well as generating abnormalities in 39-50% of zygotes. The results of the dolastane diterpene showed no evidence of inhibition in the zygotes' development, thought it was proved to induce anomalies. At higher concentrations (25 and 50 µg [mL.sup.-1]), it was possible to observe cell lyses. Keywords: natural products, diterpenes, brown seaweed, dolastanes, Lytechinus variegatus, Brazil.

Marine organisms are rich sources of natural products that, among other activities, help to maintain the species equilibrium. Samples of the marine brown alga Canistrocarpus cervicornis (Kützing) De Paula & De Clerck were collected in Búzios, Rio de Janeiro, Brazil, in June 2006. The extract was obtained in CH2Cl2 and subjected to fractionation by chromatographic methods in order to isolate and purify the compound (4R, 7R, 14S)-4α, 7α-diacethoxy-14-hydroxydolastane-1(15), 8-dien. Then, the effects of the extract and the dolastane diterpene on zygotes and gametes of the sea urchin Lytechinus variegatus were evaluated. The exposure of male and female gametes to the C. cervicornis extract promoted, respectively, a reduction of 10-30% in fertilization and a 20 to 70% decrease in the number of eggs. Furthermore, the exposure of zygotes to the extract inhibited their development up to 86.7 ± 1.6% (at a concentration of 250 µg mL^sup -1^), as well as generating abnormalities in 39-50% of zygotes. The results of the dolastane diterpene showed no evidence of inhibition in the zygotes' development, thought it was proved to induce anomalies. At higher concentrations (25 and 50 µg mL^sup -1^), it was possible to observe cell lyses. [PUBLICATION ABSTRACT]

Los organismos marinos son fuentes ricas en productos naturales que, entre otras actividades, ayudan a mantener el equilibrio entre las especies. Se colectaron muestras de Canistrocarpus cervicornis (Kützing) De Paula & De Clerck en Armação de Buzios, Estado de Rio de Janeiro, Brasil, durante junio de 2006 y se sometieron a extracción en C[H.sub.2][Cl.sub.2] hasta obtener un extracto bruto. Mediante técnicas tradicionales de fitoquímica se aisló y purificó el producto natural mayoritario dolastano (4R, 7R, 14S)-4α, 7α- diacetoxi-14hidroxidolasta-1(15),8-dieno. Posteriormente, se evaluaron los efectos en diferentes concentraciones del extracto bruto en gametos y del extracto bruto y dolastano en cigotos del erizo de mar Lytechinus variegatus. Los resultados sugieren que cuando los gametos son expuestos al extracto bruto se promueve una disminución en las tasas de fecundación, 10 a 30% (espermatozoides) y de 20 a 70% (óvulos). Además, cuando los cigotos fueron expuestos al extracto bruto se inhibió el desarrollo en un 86,7% [+ ó -]1,6 (250 [micrón]g [mL.sup.-1]) y se generaron cigotos anormales que variaron entre 39 y 50%. Los resultados de los experimentos con el dolastano no mostraron evidencias de inhibición del desarrollo embrionario. Sin embargo, se constató la inducción de anomalías y en las mayores concentraciones (25 y 50 [micrón]g [mL.sup.-1]) se registró el evento de lisis en los cigotos.