# Marine-Originated Materials and Their Potential Use in Biomedicine
## 2 Seaweed-Originated Components
#### Biomedical and Food Applications of seaweed-Originated Components  
Seaweeds have been thoroughly studied for their nutritional composition. Based on the rich bioactive compounds that are found in seaweeds, the wide use of them has been linked to a healthy and beneficial diet. Several analyses have shown that the levels of proteins, proline, lipids, polyphenols, chlorophyll contents, dietary fibers, and carbohydrates that are included in seaweeds are high [27]. Apart from proline, essential amino acids, such as methionine, lysine, valine, and phenyl alanine, are found in significant levels in seaweed's composition [28]. Furthermore, linolenic acid and \(\alpha\)-linolenic acid, which are fatty acids with high nutritional value, and vitamins (mainly vitamin C) are among the main ingredients of seaweeds [29]. Thus, it is reasonable that seaweeds might be used as nutritional supplements. Many studies have thoroughly analyzed the composition of seaweeds, indicating that they are rich in essential minerals, such as iron, magnesium, calcium, potassium, zinc, selenium, copper, iodine, phosphorus, and fluoride [30]. Other studies have focused on the vitamins that are found in seaweeds, such as A, B1, B2, B9, B12, C, D, E, K, riboflavin, folic acid, and pantothelic acid. In particular, _Porphyna umbilicalis, Himanthalia elongata_, and _Crassibycus changii_ are among the species that are rich in vitamin C [8]. [PERSON] et al., analyzing the nutritional composition of _G. acerosa_ and _S. wightii_, proposed their use as potential food supplements [24]. Thus, the common point of these studies is that they propose seaweeds as low-caloric, nutritive foods [23]. Marine pharmaceuticals is a quite modern branch of pharmacology. The possible use of seaweed compounds for the development of natural drugs is among the scopes of this scientific field. Seaweeds have been used in biomedicine, mainly in Asian countries, since ancient times [7]. According to [PERSON] et al., marine organisms, like algae, are a source of various bioactive compounds, such as sulfated polysaccharides, and although they are a defensive barrier against any infective organism, protecting algae, they might also be used in biomedicine, due to their anti-inflammatory, antitumor, antiviral, and antimicrobial potentials, which are mainly used in tissue engineering or in drug delivery system development [31]. Furthermore, various studies have indicated that seaweeds provide antioxidant and enzyme inhibitory effects [32]. Moreover, alkaloids, terpenoids, and steroids have been detected in brown algae (genus _Cystoseira_) in the Mediterranean Sea, and [PERSON] et al. have focused on their pharmaceutical potential [33]. Brown seaweeds contain fucoidan rich in sulphate ester groups; L-fucose; monosaccharides, such as glucose and galactose; and uronic acids [34]. [PERSON] et al. have studied the pharmacokinetics of fucoidan of Fucus vesicolus in their study involving post-administration to rats [35]. Generally, marine polysaccharides, e.g., fucoidan, have proven to be effective against herpes virus strains such as enterovirus (ECHO-1), human immunodeficiency virus (HIV-1), Herpes Simplex Virus type 1 (HSV-1), and Herpes Simplex Virus type 2 (HSV-2), according to [PERSON] et al. [36]. Koppaphycus, Chondrus, and Eucheuma red seaweed species contain carrageenann with antivirus potential against HSV-1 and HSV-2 in vitro [37]. Elatol from red algae has shown antibacterial properties against _Staphylococcus epidermidis_, _Salmonella_ sp., and _Klebsiella pneumoniae_[38]. Also, laminarin and alginate are found in brown seaweeds. Laminarin is a linear polysaccharide that is mainly used in biomedicine. It has immunostimulatory activity, activating macrophages possessing antitumor and auto-healing properties [39]. It is worth mentioning that, upon irradiation with gamma rays, laminarin's antioxidant behavior is enhanced [40]. Alginate is a biopolymer, with very good stabilizing properties. It is used in food products and in medicine [41].