Marine-Derived Antimitotic Potential of Lombok Fucus vesiculosus: Dose-Dependent Cleavage Arrest in Diadema antillarum Embryos

Abstract

Brown macroalgae are increasingly investigated as sources of antiproliferative metabolites, but phenotypic evidence linking crude algal extracts to stage-specific mitotic disruption remains limited. This study re-evaluates an exploratory laboratory experiment examining the effect of an ethanol extract of brown alga identified as Fucus vesiculosus from Lombok coastal waters on early development of the sea urchin Diadema antillarum. Adult sea urchins were conditioned separately by sex; gametes were obtained and fertilized, and embryos were exposed to five extract concentrations (1.0, 2.5, 4.0, 5.0, and 5.5 mg/100 mL). Twenty embryos were followed per condition, with progression assessed from zygote through cleavage, blastula, gastrula, and pluteus stages. A clear concentration-dependent loss of developmental progression was observed. At 1.0 mg/100 mL, 90% of embryos reached the 32-cell stage but none progressed to blastula. At 2.5 mg/100 mL, 60% reached 16 cells and development stopped before 32 cells. At 4.0 mg/100 mL, only 25% reached 8 cells. At 5.0 and 5.5 mg/100 mL, only 10% and 5%, respectively, reached the 8-cell stage, with arrest apparent from the earliest cleavages. These staged phenotypes support a dose-responsive antimitotic or embryotoxic effect of the crude ethanol extract. Updated evidence on fucoidan- and phlorotannin-rich F. vesiculosus preparations provides biological plausibility through cell-cycle arrest, apoptosis, and suppression of proliferative signaling. However, because the extract was not chemically standardized and the assay was descriptive, the results should be interpreted as a phenotypic screening signal rather than proof of anticancer efficacy. The principal novelty is the demonstration of a graded cleavage-stage arrest pattern in D. antillarum across five extract doses using locally sourced material, providing a foundation for modern fractionation, molecular identification, and mechanism-focused validation