60
Seaweeds are rich in antioxidants as they possess diverse functional polysaccharides. Similarly, β-glucan extracted from barley exerts significant antioxidant activity, in addition to other various biological activities. The magnitude of antioxidant
activity exhibited by β-glucan is a function of different physiologic properties (e.g.,
structure and molecular size) of the β-glucan. This is also dependent on the source
of the β-glucan and extraction method that is used (Kofuji et al. 2012).
The antioxidant activities of Lycium barbarum Polysaccharides (LBP) is an
example of antioxidant polysaccharide that has been widely studied. Lycium barbarum is being used traditionally in China as a food supplement and medicinal herb
(Gao et al. 2017). LBPs displayed significant radical scavenging effect on ABTS,
DPPH as well as superoxide radicals (Zhang et al. 2014b). Furthermore, LBPs
exhibited significant reducing power, ferrous ion chelating potency, and superoxide
scavenging ability (He et al. 2012; Jin et al. 2013). All these stated antioxidant activities of LBPs is as a result of the plant’s ability to improve the activities of antioxidant enzymes such as glutathione peroxidase (GSH-Px) and superoxide
dismutase (SOD).
A water-soluble polysaccharide was extracted from Hyriopsis cumingii (HCp)
by Hu et al. (2010). The polysaccharide has a structural component of ɑ – (1 → 4) –
D-glucan branched with a single ɑ- D-glucose at C-6 of every five residues on average and an average molecular weight of about 2.65X 10
5
. Pharmacological studies
revealed that this polysaccharide significantly increases the total SOD activity of
brain tissue and lowers malondialdehyde content effectively (Hu et al. 2010). In
another study, Ngo et al. (2008) identified the antioxidant effects of chitosan
Oligosaccharides (NA-COS) which is produced by acidic hydrolysis of crab chitin.
Their study indicated that NA-COS have significant potentials for scavenging freeradical in a cellular system. They were shown to inhibit myeloperoxidase activity as
well as reduce free-radical oxidation of DNA and membrane proteins. They were
also shown to stimulate an increase in intracellular gluthathione levels.
4.7.3 Immunomodulatory and Immunostimulatory Activities
One of the desirable features of the innate immune system is to quickly recognize
and respond to an invading pathogen so as to control infection. There are different
types of natural immunotherapeutic operators that incorporate monoclonal antibodies, malignant growth immunizations, interferons, interleukins, state invigorating
variables, colony-stimulating factors, gene therapy, and non-specific immunemodulating agents (Pandya et al. 2018). A wide scope of polysaccharides is likewise
equipped for connecting with the immune system to upregulate or downregulate
explicit portion of the host reaction and can, therefore, be classified as immune
modulators (Wang et al. 2013).
The immunomodulatory properties of naturally derived polysaccharides which
include heteroglycans and proteoglycans have been recognized and documented.
Such polysaccharides are of certain molecular weight and structure. Their immunoT. A. Oyedepo and A. A. A. Kayode
Seaweeds are rich in antioxidants as they possess diverse functional polysaccharides. Similarly, β-glucan extracted from barley exerts significant antioxidant activity, in addition to other various biological activities. The magnitude of antioxidant
activity exhibited by β-glucan is a function of different physiologic properties (e.g.,
structure and molecular size) of the β-glucan. This is also dependent on the source
of the β-glucan and extraction method that is used (Kofuji et al. 2012).
The antioxidant activities of Lycium barbarum Polysaccharides (LBP) is an
example of antioxidant polysaccharide that has been widely studied. Lycium barbarum is being used traditionally in China as a food supplement and medicinal herb
(Gao et al. 2017). LBPs displayed significant radical scavenging effect on ABTS,
DPPH as well as superoxide radicals (Zhang et al. 2014b). Furthermore, LBPs
exhibited significant reducing power, ferrous ion chelating potency, and superoxide
scavenging ability (He et al. 2012; Jin et al. 2013). All these stated antioxidant activities of LBPs is as a result of the plant’s ability to improve the activities of antioxidant enzymes such as glutathione peroxidase (GSH-Px) and superoxide
dismutase (SOD).
A water-soluble polysaccharide was extracted from Hyriopsis cumingii (HCp)
by Hu et al. (2010). The polysaccharide has a structural component of ɑ – (1 → 4) –
D-glucan branched with a single ɑ- D-glucose at C-6 of every five residues on average and an average molecular weight of about 2.65X 10
5
. Pharmacological studies
revealed that this polysaccharide significantly increases the total SOD activity of
brain tissue and lowers malondialdehyde content effectively (Hu et al. 2010). In
another study, Ngo et al. (2008) identified the antioxidant effects of chitosan
Oligosaccharides (NA-COS) which is produced by acidic hydrolysis of crab chitin.
Their study indicated that NA-COS have significant potentials for scavenging freeradical in a cellular system. They were shown to inhibit myeloperoxidase activity as
well as reduce free-radical oxidation of DNA and membrane proteins. They were
also shown to stimulate an increase in intracellular gluthathione levels.
4.7.3 Immunomodulatory and Immunostimulatory Activities
One of the desirable features of the innate immune system is to quickly recognize
and respond to an invading pathogen so as to control infection. There are different
types of natural immunotherapeutic operators that incorporate monoclonal antibodies, malignant growth immunizations, interferons, interleukins, state invigorating
variables, colony-stimulating factors, gene therapy, and non-specific immunemodulating agents (Pandya et al. 2018). A wide scope of polysaccharides is likewise
equipped for connecting with the immune system to upregulate or downregulate
explicit portion of the host reaction and can, therefore, be classified as immune
modulators (Wang et al. 2013).
The immunomodulatory properties of naturally derived polysaccharides which
include heteroglycans and proteoglycans have been recognized and documented.
Such polysaccharides are of certain molecular weight and structure. Their immunoT. A. Oyedepo and A. A. A. Kayode