Antimitotic effect of an extract of the sea anemone bunodosoma caissarum on sea urchin EGG development

A methanolic extract of the sea anemone Bunodosoma caissarum has an antimiototic effect on sea urchin egg development. The extract produces a dose-dependent inhibition of cell cleavage. When the extract is alded together with sperm to unfertilized sea urchin eggs, the ED50 is 0.60 ñ 0.03 mg/ml (x ñ SEM). When added shortly after fertilization, the extract produces the same kind of progressive inhibition but with an ED50 of 0.98 ñ 0.16 mg/ml. In the first case, detachment of the vitelline layer is inhibited whereas in the second case the extract inhibits cleavage even when the membrane is present