230
responsible for its color (Robic et al. 2009). Red seaweeds owe their color to phycoerythrin and phycocyanin (McHugh 2003). In terms of health, the consumption of
polysaccharides extracted from edible seaweeds has been linked to a significant
reduction in total cholesterol, low-density lipoproteins and plasma TG (Amano
et al. 2005). Polysaccharides extracted from seaweeds showed hypo-cholesterolemic effects due to their increased interference with micelle development and
absorption of lipids and biliary acids. Moreover, sulfated polysaccharides (carrageenans and fucoidan) have several important biological functions: antioxidant
(Heo et al. 2005), antiviral (Artan et al. 2008), anti-inflammatory (Kim et al. 2009)
and anticoagulant (Matsubara et al. 2000). Thus, their potential has been employed
in cosmetics, functional foods and pharmaceuticals (d’Ayala et al. 2008).
13.1.9 Phytosterols
The structure of phytosterols and cholesterol is similar. The only difference between
them is the relative positioning of the methyl and ethyl groups. In plants, phytosterols exist in the form of beta-sitosterols, campesterol and stigmasterol, while in
marine invertebrates these phytosterols exist in the form of stanols, sterols and sterol esters (Kanazawa 2001). Phytosterols play an important role in the production of
healthy food products like milk, fat free or low-fat yogurt, spreads, juice, bread and
cereals (Demonty et al. 2009). In clinical trials, an intake of 2–3 g/day of phytosterols has significantly reduced LDL-cholesterol (Malinowski and Gehret 2010).
Moreover, edible microalgae containing phytosterols have proven hypocholesterolemic effects (Plaza et al. 2009). Phytosterols reduce the uptake of cholesterol in the
gut since they bind to micelles in the small intestine. Also, phytosterols enhance the
action of the ATP-binding cassette G-proteins in the enterocytes via excretion of
cholesterol in the lumen (Marangoni and Poli 2010). Other biochemical actions of
phytosterols include their antioxidant (Mannarino et al. 2009), anti-inflammatory
(Houweling et al. 2009) and anticancer activities (Bouic 2001). Musa-Veloso et al.
(2011) have hypothesized the cardio-protective effects of phytosterols against coronary heart disease and have reported that an intake of ≥2 g/day of phytosterols significantly lowers LDL-cholesterol.
13.1.10 Carotenoids
Carotenoids (fat-soluble) contain orange and yellow pigments and have the ability
to convert light into chemical energy. Carotenoids comprise antioxidants that prevent reactive oxygen species-induced damage in fungi, plankton and other photosynthetic organisms (Lesser 2006). Carotenoids (e.g. β-carotene) play important
roles in many biological processes, such as the formation of vitamin A in the body
(García-González et al. 2005). Other examples of carotenoids include lycopene,
S. Hassan et al.
responsible for its color (Robic et al. 2009). Red seaweeds owe their color to phycoerythrin and phycocyanin (McHugh 2003). In terms of health, the consumption of
polysaccharides extracted from edible seaweeds has been linked to a significant
reduction in total cholesterol, low-density lipoproteins and plasma TG (Amano
et al. 2005). Polysaccharides extracted from seaweeds showed hypo-cholesterolemic effects due to their increased interference with micelle development and
absorption of lipids and biliary acids. Moreover, sulfated polysaccharides (carrageenans and fucoidan) have several important biological functions: antioxidant
(Heo et al. 2005), antiviral (Artan et al. 2008), anti-inflammatory (Kim et al. 2009)
and anticoagulant (Matsubara et al. 2000). Thus, their potential has been employed
in cosmetics, functional foods and pharmaceuticals (d’Ayala et al. 2008).
13.1.9 Phytosterols
The structure of phytosterols and cholesterol is similar. The only difference between
them is the relative positioning of the methyl and ethyl groups. In plants, phytosterols exist in the form of beta-sitosterols, campesterol and stigmasterol, while in
marine invertebrates these phytosterols exist in the form of stanols, sterols and sterol esters (Kanazawa 2001). Phytosterols play an important role in the production of
healthy food products like milk, fat free or low-fat yogurt, spreads, juice, bread and
cereals (Demonty et al. 2009). In clinical trials, an intake of 2–3 g/day of phytosterols has significantly reduced LDL-cholesterol (Malinowski and Gehret 2010).
Moreover, edible microalgae containing phytosterols have proven hypocholesterolemic effects (Plaza et al. 2009). Phytosterols reduce the uptake of cholesterol in the
gut since they bind to micelles in the small intestine. Also, phytosterols enhance the
action of the ATP-binding cassette G-proteins in the enterocytes via excretion of
cholesterol in the lumen (Marangoni and Poli 2010). Other biochemical actions of
phytosterols include their antioxidant (Mannarino et al. 2009), anti-inflammatory
(Houweling et al. 2009) and anticancer activities (Bouic 2001). Musa-Veloso et al.
(2011) have hypothesized the cardio-protective effects of phytosterols against coronary heart disease and have reported that an intake of ≥2 g/day of phytosterols significantly lowers LDL-cholesterol.
13.1.10 Carotenoids
Carotenoids (fat-soluble) contain orange and yellow pigments and have the ability
to convert light into chemical energy. Carotenoids comprise antioxidants that prevent reactive oxygen species-induced damage in fungi, plankton and other photosynthetic organisms (Lesser 2006). Carotenoids (e.g. β-carotene) play important
roles in many biological processes, such as the formation of vitamin A in the body
(García-González et al. 2005). Other examples of carotenoids include lycopene,
S. Hassan et al.