Osteogenic activity of non-genotoxic sulfated polysaccharides from the green seaweed Caulerpa sertularioides

Biocompatibility is a requirement for new molecules with potential applications in bone regeneration. Molecules with such potential applications in regenerative medicine include sulfated polysaccharides (SPs) isolated from seaweed. In this study, we evaluated the cytotoxicity and genotoxicity of SPs extracted from the green seaweed, Caulerpa sertularioides, and demonstrated its osteogenic activity in human mesenchymal stem cells (hMSCs). Seaweed samples were collected along the coast of Rio Grande do Norte, Brazil, and the results of chemical composition analyses of the samples revealed a high sugar and sulfate content. hMSCs treated with seaweed SPs (1–10 μg/mL) did not alter 3-(4,5-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction activity, and alkaline phosphatase activity was increased by approximately 30–40% when cells were treated with 5–10 μg/mL SPs. In addition, 21 days of continuous treatment resulted in increased calcium deposition in the extracellular matrix. Comet assay and the cytokinesis-block micronucleus cytome assay did not reveal significant changes in the frequency of nuclear alterations after 24 h of treatment. Together, our results show, for the first time, the osteogenic activity and non-genotoxicity of SPs from C. sertularioides, suggesting their potential in therapeutic applications in bone regeneration.