Saponins macrophage activation

Among cycloartane glycosides from Astragalus Turkish species, only astragaloside I (88) was able to stimulate NF-kB expression in macrophages. This implies that they are critical structural features responsible for macrophage activation by saponins [71]. 

Protection of rats from devl. of Pseudomonas aeruginosa infections Activation of multiple effector pathwaye (Tcells, Bcells, macrophages) Protection of mice from devl. of C. albicans infection (macrophages) Polysaccharides as antineoplastic immunostimulators (NK cells) Proliferative responses of blood lymphocytes Protection of ginseng saponins of immunosuppression in mice Inhibition on bacterial endotoxin-induced embryolethality in rats Induction of neutrophil accumulation in mice... 

A panel of standardized in vitro assays used to evaluate this activity was described by Wagner and Jurcic (1991) [56], Many saponins were shown able to modify in vitro non specific (both humoral and cellular) immune functions in a non antigen-dependent manner. As summarized in Table 3, they showed a mitogenic effect in lymphocytes cultures, the activation of macrophages and granulocytes and they influenced the production of cytokines. 

Some saponins have been shown to 1) stimulate phagocytosis by both macrophages and granulocytes [21-24], 2) elevate the level of activated complement [21], and 3) activate naturd killer cells (NK cells) and cause interferon-y (IFN-y) production [25]. 

Many saponins have been proven to be able to modify non-specific (both humoral and cellular) immune functions in vitro in a non-antigen-dependent manner. Here we will present a brief review on their influence on lymphocytes, macrophages, and granulocytes together with their influence on the liberation of cytokines and the activation of NK cells. Few in vivo studies have been performed in order to prove the significance of saponins as immunostimulants. 

The in vivo antitumoral effect of Virgaureasaponin E (34) in the mouse tumor models (sarcoma 180 and DBA2/MC.SC-1 fibrosarcoma models) could be due, at least in part, to an immunostimulant activity [69]. The ability of virgaureasaponin E (34) to reduce the tumor size by stimulating the immune system could be a consequence of stimulated immune parameters detected in ex vivo assays (proliferation and phagocytosis of bone marrow macrophage cells, release of TNFa in the blood of mice treated with the saponin after EPS induction) [69]. 

Sanqi decoction stimulated the activities of natural killer cells, macrophages, and plaqueforming cells while crude polysaccharides stimulated the activities of only macrophages and plaque-forming cells in mice sanchi-nan-A (a polysaccharide) has activating effects on the reticuloendothelial system as per the carbon clearance test in mice. Similar immunomodulatory properties have recently been reported for the saponin and polysaccharide fractions. 

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