*Literature Search*

The preferred reporting items for systematic reviews were used for the collection, identification, screening, selection, and analysis of the studies reviewed. A literature search was performed using different databases, including Scopus, Web of Science, Google Scholar, Wiley, MDPI, and PubMed. The search criteria included scientific articles on seaweeds published between 1989 and 2022. The keywords used in the literature search were "seaweeds" and "bioactivites OR "biological activities" OR "safety" OR "toxicity" OR "characteristics" OR "structure" OR "anticancer" OR "antidiabitics" OR "lipids" OR "polysaccarides" OR "phenolic compounds" OR "vitamines" OR "cosometics" OR "foods" OR "human" OR "minerals" OR "pigments and carotenoids" OR "protein" OR "amino acids". The total number of articles found was 650. Studies focusing on the above keywords were selected, as well as those addressing the biological activity of seaweeds and the different applications of seaweeds. The figures were obtained from MDPI journals, and the chemical structure of compounds was designed by Chem windo 6 ver.4.1.1 Biorad edition.
