8.7 Applications
181
8.7.1 Immune Modulation
The ability of certain substances to influence immune response is referred to as
immunomodulation and entities which are able to do these are referred to as
immunomodulators. This activity is primarily dependent on the activation of inflammatory process whereby the body releases chemicals to destroy pathogens from the
body. Ulvans aids in immunomodulatory process by activating the protein complexes
which control production of cytokines which are key to the inflammatory process.
Increased production of cytokines, enzymes and the products has been shown by
macrophage cells treated with ulvan from species of U. pertusa (Li et al. 2018a,
b), U. rigida (Leiro et al. 2007), U. intestinalis (Peasura et al. 2016), U. Ohnoi
(Fernández-Díaz et al. 2017) Enteromorpha prolifera (Kim et al. 2011a) and U. prolifera (Cho et al. 2010). Beyond macrophage cell studies, investigation of immunomodulatory activity of ulvans has also been carried out in organisms such as fish (Castro et al. 2006), rats, mice and chickens. Ulvans aid in the bodies’ defense against
defective or pathogenes by enhancing macrophage functions such as phagocytosis
(Karnjanapratum et al. 2012).
The inflammatory cytokine production, hence immunomodulatory activity of
ulvan, is comparable to that of lipopolysaccharides albeit requiring a higher concentration of ulvan to achieve the same effect. For instance in one study, a 500 µg mL
of ulvan was required to achieve the same immunomodulatory effect as 100 ng/mL
of lipopolysaccharides.
Molecular weight and degree of sulfation jointly affect the occurrence and potency
of the immunomodulatory activity of ulvans. Purity is also an important factor in
the effectiveness of the immunomodulatory activity of ulvans with purer samples
showing better immunomodulatory effect. This can be attributed to the reduction in
interference with the active functional groups as well as structural chemistry which
influences the bioactivity. In one study, ulvans extracted and purified from U. pertusa with molecular weight in the range 14,450–1690 kDa showed an increase in
immunomodulatory activity quantified as macrophage cell activation when compared with ulvans with lower molecular weight of less than 365 kDa from the same
source (Tabarsa et al. 2012). However, this increased immunomodulatory activity
resulting from increased molecular weight is not replicated in other ulvan extracts
from other species in a different molecular weight range. For examples, ulvan from U.
intestinalis with a molecular weight of 28.7 kDa showed much higher immunomodulatory activity compared to ulvans from same source with higher molecular weight of
87.2 kDa (Tabarsa et al. 2018), thus indicating that the relationship between molecular weight and immunomodulatory activity is not the same either across all molecular
weight range or across species. Degree of sulfation also affects the immunomodulatory activity of ulvan. Most studies show that higher level of immunomodulation is
achieved with higher degree of sulfation (Leiro et al. 2007).
The immunomodulatory activity of ulvans makes them potentially applicable
as immune-stimulating agents if nutraceutical or pharmaceutical products. Species
of green algae not yet confirmed to possess or do not possess immunomodulatory
181
8.7.1 Immune Modulation
The ability of certain substances to influence immune response is referred to as
immunomodulation and entities which are able to do these are referred to as
immunomodulators. This activity is primarily dependent on the activation of inflammatory process whereby the body releases chemicals to destroy pathogens from the
body. Ulvans aids in immunomodulatory process by activating the protein complexes
which control production of cytokines which are key to the inflammatory process.
Increased production of cytokines, enzymes and the products has been shown by
macrophage cells treated with ulvan from species of U. pertusa (Li et al. 2018a,
b), U. rigida (Leiro et al. 2007), U. intestinalis (Peasura et al. 2016), U. Ohnoi
(Fernández-Díaz et al. 2017) Enteromorpha prolifera (Kim et al. 2011a) and U. prolifera (Cho et al. 2010). Beyond macrophage cell studies, investigation of immunomodulatory activity of ulvans has also been carried out in organisms such as fish (Castro et al. 2006), rats, mice and chickens. Ulvans aid in the bodies’ defense against
defective or pathogenes by enhancing macrophage functions such as phagocytosis
(Karnjanapratum et al. 2012).
The inflammatory cytokine production, hence immunomodulatory activity of
ulvan, is comparable to that of lipopolysaccharides albeit requiring a higher concentration of ulvan to achieve the same effect. For instance in one study, a 500 µg mL
of ulvan was required to achieve the same immunomodulatory effect as 100 ng/mL
of lipopolysaccharides.
Molecular weight and degree of sulfation jointly affect the occurrence and potency
of the immunomodulatory activity of ulvans. Purity is also an important factor in
the effectiveness of the immunomodulatory activity of ulvans with purer samples
showing better immunomodulatory effect. This can be attributed to the reduction in
interference with the active functional groups as well as structural chemistry which
influences the bioactivity. In one study, ulvans extracted and purified from U. pertusa with molecular weight in the range 14,450–1690 kDa showed an increase in
immunomodulatory activity quantified as macrophage cell activation when compared with ulvans with lower molecular weight of less than 365 kDa from the same
source (Tabarsa et al. 2012). However, this increased immunomodulatory activity
resulting from increased molecular weight is not replicated in other ulvan extracts
from other species in a different molecular weight range. For examples, ulvan from U.
intestinalis with a molecular weight of 28.7 kDa showed much higher immunomodulatory activity compared to ulvans from same source with higher molecular weight of
87.2 kDa (Tabarsa et al. 2018), thus indicating that the relationship between molecular weight and immunomodulatory activity is not the same either across all molecular
weight range or across species. Degree of sulfation also affects the immunomodulatory activity of ulvan. Most studies show that higher level of immunomodulation is
achieved with higher degree of sulfation (Leiro et al. 2007).
The immunomodulatory activity of ulvans makes them potentially applicable
as immune-stimulating agents if nutraceutical or pharmaceutical products. Species
of green algae not yet confirmed to possess or do not possess immunomodulatory