nobile yields sesquiterpene glycosides Dendroside A, Dendronobilosides A, and B
that exerts proliferative effects on lymphocytes. Flavonoids are another class of
phytocompounds that exerts immunomodulatory effects. Lasure et al. (1994)
reported the effect of flavonoids on the activation of complements using hemolytic
assay and found that quercetin, quercitrin, rutin, myricetin, taxifolin, pelargonidin
chloride, and cyanidin chloride inhibited the classical pathway, while hyperoside,
myricetin, baicalein, and pelargonidin chloride inhibited the alternative pathway in
a dose-dependent manner. Besides other flavonoids viz apigenin, anthocyanidins,
flavones, isoflavonoids, and oligomeric proanthocyanidins found in plants like
Terminalia arjuna exhibit immunomodulatory activity. Furthermore, these phenolic
compounds isolated from (Euphorbiaceae) family also stop the classical pathway of
complement activation. Coumarin glycosides isolated from Achillea millefolium,
Citrus natsudaidai and Heracleum persicum revealed immunomodulatory properties. Hydroxycoumarins like Esculin, Esculetin, and Scopoletin improve
complement-mediated hemolysis. Esculentin a class of 6,7-dihydroxycoumarin
isolated from Euphorbia lathyris, Citrus limonia, and Artemisia capillaris attributed to a wide range of immunomodulatory properties like free radical scavenging,
protecting DNA against oxidative damage (Leung et al. 2005). It also shows cancer
chemopreventive, antitumor, lipoxygenase-inhibitory activity, and tyrosinaseinhibitory activity. Certain plants and plant-derived bioactive compounds like
polysaccharides and lipopolysaccharides can activate the alternative pathway of
complement activation and hence play a key role in the regulation of inflammation.
Moreover, bioactive Rosmarinic acid from Rosmarinus officinalis L. inhibits the
complement system via blocking both the classical and alternative pathways of
complement activation (Fig. 6.5).
6.2.4 High Molecular Weight Immunomodulators
The compound having High molecular weight like polysaccharides show
immunomodulatory action primarily on the innate arm of the immune system and
specifically by enhancing the phagocytosis of granulocytes and affecting the
macrophages functions. Polysaccharide obtained from the plant Cistanche deserticola enhanced the proliferation of murine thymus lymphocytes. Compounds
isolated from Salicornia herbacea show anticancer properties via activating
monocytic cells and inducing differentiation of monocytes into macrophages (Rios
2010). Axillary mode of action includes induced interferons, interleukins, and
complement activation. The binding sites for several polysaccharides to immune
components might vary. Xyloglucans (doRosa’rio et al. 2011), glucuronic
acid-containing arabinogalactan and methyl glucuronoxylans, play a critical role in
stimulating the phagocytes (Luettig et al. 1989). The complement-activating
polysaccharides comprise acidic polygalacturonans isolated from E. purpurea.
Polygalacturonans are also active for activating macrophages to counteract tumor
cells and to destroy intracellular pathogens like Candida albicans, Leishmania
6 Natural Compounds Extracted from Medicinal Plants …
223
that exerts proliferative effects on lymphocytes. Flavonoids are another class of
phytocompounds that exerts immunomodulatory effects. Lasure et al. (1994)
reported the effect of flavonoids on the activation of complements using hemolytic
assay and found that quercetin, quercitrin, rutin, myricetin, taxifolin, pelargonidin
chloride, and cyanidin chloride inhibited the classical pathway, while hyperoside,
myricetin, baicalein, and pelargonidin chloride inhibited the alternative pathway in
a dose-dependent manner. Besides other flavonoids viz apigenin, anthocyanidins,
flavones, isoflavonoids, and oligomeric proanthocyanidins found in plants like
Terminalia arjuna exhibit immunomodulatory activity. Furthermore, these phenolic
compounds isolated from (Euphorbiaceae) family also stop the classical pathway of
complement activation. Coumarin glycosides isolated from Achillea millefolium,
Citrus natsudaidai and Heracleum persicum revealed immunomodulatory properties. Hydroxycoumarins like Esculin, Esculetin, and Scopoletin improve
complement-mediated hemolysis. Esculentin a class of 6,7-dihydroxycoumarin
isolated from Euphorbia lathyris, Citrus limonia, and Artemisia capillaris attributed to a wide range of immunomodulatory properties like free radical scavenging,
protecting DNA against oxidative damage (Leung et al. 2005). It also shows cancer
chemopreventive, antitumor, lipoxygenase-inhibitory activity, and tyrosinaseinhibitory activity. Certain plants and plant-derived bioactive compounds like
polysaccharides and lipopolysaccharides can activate the alternative pathway of
complement activation and hence play a key role in the regulation of inflammation.
Moreover, bioactive Rosmarinic acid from Rosmarinus officinalis L. inhibits the
complement system via blocking both the classical and alternative pathways of
complement activation (Fig. 6.5).
6.2.4 High Molecular Weight Immunomodulators
The compound having High molecular weight like polysaccharides show
immunomodulatory action primarily on the innate arm of the immune system and
specifically by enhancing the phagocytosis of granulocytes and affecting the
macrophages functions. Polysaccharide obtained from the plant Cistanche deserticola enhanced the proliferation of murine thymus lymphocytes. Compounds
isolated from Salicornia herbacea show anticancer properties via activating
monocytic cells and inducing differentiation of monocytes into macrophages (Rios
2010). Axillary mode of action includes induced interferons, interleukins, and
complement activation. The binding sites for several polysaccharides to immune
components might vary. Xyloglucans (doRosa’rio et al. 2011), glucuronic
acid-containing arabinogalactan and methyl glucuronoxylans, play a critical role in
stimulating the phagocytes (Luettig et al. 1989). The complement-activating
polysaccharides comprise acidic polygalacturonans isolated from E. purpurea.
Polygalacturonans are also active for activating macrophages to counteract tumor
cells and to destroy intracellular pathogens like Candida albicans, Leishmania
6 Natural Compounds Extracted from Medicinal Plants …
223