3.2.2. Role of Proteins and Amino Acid in Cosmeceuticals

Because several amino acids are components of the natural moisturizing factor (NMF) in human skin, they are commonly used as moisturizing agents in cosmetic preparations [113,114]. MAA content is higher in the summer and at a mild depth (0–1 m). MAAs have the ability to be used in cosmetic products and uses as ultraviolet protectors and cell proliferation stimulators [115].

Algae protein concentration differs significantly among the different algae groups (brown, red, and green). Brown algae have a lower protein concentration (5–24%) of dry weight, while red and green algae have a greater protein concentration (10–47%) of dry weight [116]. Holdt and Kraan [107] show that protein, peptide, and amino acid concentration, like other bioactive components of algae, is affected by a variety of circumstances, including seasonal change. During the months from February to May, for example, brown algae Saccharina and Laminaria had the highest protein content [107]. A similar trend was observed in red algae species, with a high concentration of protein in the summer and a significant decrease in the winter [116]. Algae proteins are high in glycine, arginine, alanine, and glutamic acid, and they include essential amino acids at amounts comparable to FAO/WHO needs. Lysine and cystine are their limiting amino acids [117]. Taurine, laminin, kainoids, kainic and domoic acids, and several mycosporin-type amino acids are also found in algae [118]. Taurine is involved in several physiological activities in the human body, including immunomodulation, membrane stabilization, ocular development, and nervous system function [119]. Furthermore, kainic and domoic acids play a role in the control of neurophysiological functions [120].
