Seaweeds have attracted high interest in recent years due to their chemical and bioactive properties to find new molecules with valuable applications for humankind. Phenolic compounds are the group of metabolites with the most structural variation and the highest content in seaweeds. The most researched seaweed polyphenol class is the phlorotannins, which are specifically synthesized by brown seaweeds, but there are other polyphenolic compounds, such as bromophenols, flavonoids, phenolic terpenoids, and mycosporine-like amino acids. The compounds already discovered and characterized demonstrate a full range of bioactivities and potential future applications in various industrial sectors. This review focuses on the extraction, purification, and future applications of seaweed phenolic compounds based on the bioactive properties described in the literature. It also intends to provide a comprehensive insight into the phenolic compounds in seaweed.

The aim of this paper is to review the multiplicity of the current uses of marine macroalgae. Seaweeds are already used in many products and for different purposes, from food products to medicine. They are a natural resource that can provide a number of compounds with beneficial bioactivities like antioxidant, anti-inflammatory, anti-aging effects, among others. Despite studies directed in prospecting for their properties and the commodities already marketed, they could, surely, be even more researched and sustainably explored.

The world population is continuously growing, so it is important to keep producing food in a sustainable way, especially in a way that is nutritious and in a sufficient quantity to overcome global needs. Seaweed grows, and can be cultivated, in seawater and generally does not compete for arable land and freshwater. Thus, the coastal areas of the planet are the most suitable for seaweed production, which can be an alternative to traditional agriculture and can thus contribute to a reduced carbon footprint. There are evolving studies that characterize seaweed’s nutritional value and policies that recognize them as food, and identify the potential benefits and negative factors that may be produced or accumulated by seaweed, which are, or can be, dangerous for human health. Seaweeds have a high nutritional value along with a low caloric input and with the presence of fibers, proteins, omega 3 and 6 unsaturated fatty acids, vitamins, and minerals. Moreover, several seaweed sub-products have interesting features to the food industry. Therefore, the focus of this review is in the performance of seaweed as a potential alternative and as a safe food source. Here described is the nutritional value and concerns relating to seaweed consumption, and also how seaweed-derived compounds are already commercially explored and available in the food industry and the usage restrictions to safeguard them as safe food additives for human consumption.