3.2.1. Role of Proteins and Amino Acid in Medicine

Furthermore, mycosporine-like amino acids (MAAs) were revealed in a variety of species, most notably Rhodophyta: *Chondrus crispus* spp., *Grateloupia lanceola*, *Porphyra*/*Pyropia* spp., *Solieria chordalis*, *Asparagopsis armata*, *Palmaria palmata*, *Gracilaria cornea*, Gelidium, or *Curdiea racovit* [106–108]. Phycobiliproteins are made up of phycobilins, which are proteins that are covalently attached to chromophores [43]. Such water-soluble proteins have antioxidant properties and could be used as a natural food colorant [26]. PC, blue-colored phycobiliprotein derived mostly from cyanobacteria Arthrospira spp., or PE (pink-colored protein pigment) derived from cyanobacteria Lyngbya spp., both demonstrated anticancer activity upon A549 lung cancer cells [22]. Glycoproteins were also proteins found in marine algae which are made up from proteins linked to carbohydrates. Rhamnose, galactose, glucose, and mannose make up 36.24% of glycoproteins, with a mole ratio of 38:30:26:6 [109].

Protein concentrations are high in *Rhizoclonium riparium*, *Dictyota caylinica*, *Enteromorpha intestinalis*, *Catenella repens*, *Gelidiella acerosa*, *Polysiphonia mollis*, *Capsosiphon fulvescens*, *Osmundea pinnatifida*, *Sphaerococcus coronopifolius*, *Ulva lactuca*, *Gelidium microdon*, *Fucus spiralis*, *Pterocladium capillacea*, or *Ulva compressa* [110]. Anti-aging, antioxidant, anti-tumor, anti-inflammatory or protective qualities of proteins make them valuable in the prevention and treatments of neurological illnesses, DNA replication, gastric ulcers, improve response, molecule transfer, or biochemical reaction catalysis [45]. According to Cicero et al. [111], bioactive peptides can increase biological defenses against oxidative stress and inflammatory illnesses, hence boosting the real frame of nutraceutical and functional meals. As a result, MAAs have wide range of properties, such as ability to act like natural sunscreens, anti-inflammatory, antioxidants or anti-aging agents, skin renewal stimulators, cell proliferation activators, and so on, making it attractive or secure option for cosmetic industries or pharmaceutical [112].
