Smart Secondary Metabolites in Marine Environments: Exploring the Oxasqualenoid Dehydrothyrsiferol.

Dehydrothyrsiferol (DT), a brominated oxasqualenoid from the red alga Laurencia viridis, represents a compelling example of this framework. This review establishes DT as a model Smart Secondary Metabolite based on the convergence of a unique molecular architecture of rigid stereogroups connected by flexible bonds; a high metabolic yield (0.42% w/w of crude extract); potent selective bioactivity against kinetoplastids and drug-resistant tumors; multi-target modulation of protein phosphatase 2A (PP2A) and cell-surface integrins; and distinctive chemotaxonomic relevance within Macaronesian communities. Its biosynthesis proceeds through stereocontrolled epoxide-opening cascades, generating an evolutionarily refined scaffold. Ecologically, DT operates as a multifunctional shield, providing antifouling protection and deterring herbivory. Pharmacologically, it acts as a selective signaling modulator, triggering integrin-mediated cell death (IMD) in resistant cancer cells and inducing mitochondrial collapse in protozoa. In vivo studies in murine models of cutaneous leishmaniasis have demonstrated an 87% reduction in lesion size, reinforcing its promise as a lead structure.