Perilipins (PLINs) are the most abundant proteins in lipid droplets (LD). These LD-associated proteins are responsible for upgrading LD from inert lipid storage structures to fully functional organelles, fundamentally integrated in the lipid metabolism. There are five distinct perilipins (PLIN1–5), each with specific expression patterns and metabolic activation, but all capable of regulating the activity of lipases on LD. This plurality creates a complex orchestrated mechanism that is directly related to the healthy balance between lipogenesis and lipolysis. Given the essential role of PLINs in the modulation of the lipid metabolism, these proteins can become interesting targets for the treatment of lipid-associated diseases. Since reprogrammed lipid metabolism is a recognized cancer hallmark, and obesity is a known risk factor for cancer and other comorbidities, the modulation of PLINs could either improve existing treatments or create new opportunities for the treatment of these diseases. Even though PLINs have not been, so far, directly considered for pharmacological interventions, there are many established drugs that can modulate PLINs activity. Therefore, the aim of this study is to assess the involvement of PLINs in diseases related to lipid metabolism dysregulation and whether PLINs can be viewed as potential therapeutic targets for cancer and obesity.

Fucoxanthin (Fx), a marine xanthophyll carotenoid, has attracted considerable scientific attention due to its wide-ranging biological activities, including antioxidant, anti-inflammatory, anti-obesity, and anticancer effects. Despite its substantial therapeutic potential, the clinical application of Fx and its derivatives remains constrained by their structural complexity, low chemical stability, and limited bioavailability. This review offers a thorough and up-to-date overview of Fx, encompassing its primary natural sources, the metabolic biotransformation to fucoxanthinol (FxOH) and amarouciaxanthin A—metabolites whose bioactive properties significantly contribute to the observed in vivo effects—and the molecular mechanisms underlying the biological activities of Fx and its metabolites, with emphasis on their modulation of key intracellular signalling pathways involved in inflammation, lipid metabolism, and cell proliferation. Furthermore, it explores how targeted structural modifications may enhance the pharmacokinetic profiles and expand the therapeutic potential of Fx-based compounds, while highlighting promising strategies for their optimisation. By integrating insights from pharmacology, biochemistry, and synthetic chemistry, this work aims to guide future efforts in the rational design of marine-derived bioactive agents and underscores the value of marine biodiversity in therapeutic innovation.