Evaluation of the toxicological risk to humans of caulerpenyne using human hematopoietic progenitors, melanocytes, and keratinocytes in culture

The extensive growth of Caulerpa taxifolia in the Mediterranean sea produces important quantities oi bioactive secondary metabolites unable to enter the food chain. The cytotoxic effects oi caulerpenyne, the major secondary metabolite from C. taxifolia, was studied in different in vitro models: skin cells, primary cultures oi melanocytes and keratinocytes, immortalized keratinocytes (HaCaT and HESV), and bone marrow cells (hematopoietic progenitors CFU-CM). Typical dose-response curves from neutral red uptake and MTT assays were recorded in all models with IC50 ranging from 6 to 24 mu M. Hematopoietic progenitors were more sensitive to caulerpenyne than melanocyte and keratinocyte cell lines, which could be due to their higher proliferative rate. The distribution oi aggregates in colonies, macroclusters, and microclusters of hematopoietic progenitors was also altered in the presence of caulerpenyne. From our evaluation of the caulerpenyne concentrations required to result in cellular toxicity, the risks of cutaneous and/or food intoxication to humans may De considered minimal.