Anti-complementary polysaccharide

Black pepper contains several polysaccharides of which one shows a strong effect as an immune enhancer based on the fact that the polymer is an anti-complementary polysaccharide. The polysaccharide has an Mw of approx. 40 kD. It is composed basically of rhamnose, arabinose, galactose and galac-turonic acid, and shows a high binding capacity for the Yariv reagent. This indicates that the side chain of the polymer is of the arabinogalactan type II, which is a common structure for several polysaccharides with an effect on the complement system [70]. 

EPS activates complement via the alternative and classical pathways [9]. EPS is composed of lipid A, a core polysaccharide, and O-specific sugar chains. The lipid A portion activates the classical pathway, and the polysaccharide moiety activates the alternative pathway [14]. The lipid A region of EPS can interact directly with complement via an antibody-independent mechanism in which Cl is bound to lipid A [15]. Some anti-complementary polysaccharides also show an anti-inflammatory activity [16]. 

Several complement activating (anti-complementary) polysaccharides have also been isolated from the hot-water extract of several medicinal herbs (Tab. 2) [16-54], and results have been accumulated during the last ten years. The present review article deals with complement-activating polysaccharides from medicinal herbs. 

Structures of anti-complementary polysaccharides from Viscum album [RCA-N and RCA-G (A)] and from Arnica montana [A-l (B)] and related polysaccharide from Calendula officinalis [PS-Ill (C)]. 

Effects of anti-complementary polysaccharides on complement level in vivo... 

When the anti-complementary polysaccharide, LR-polysaccharide, purified from the roots of Lithospermum euchromum was injected intraperitoneally into guinea pigs (20 mg/kg or 100 mg/kg), the complement level in the blood was reduced about 30-40% in comparison with that of the control 2-12 h after the injection [23]. Visual reduction of the complement level was observed in the injected animals with the dose of 20mg/kg of the polysaccharide. This result suggests that anti-complementary polysaccharides also activate the complement system in vivo. 

Several pharmacological activities have been reported in the polysaccharides isolated from medicinal herbs (Tab. 5) [83, 84]. Anti-complementary polysaccharides also have a variety of other immunopharmacological activities. 

Anti-complementary polysaccharides have been classified into typical structural types such as arabino-P-3,6-galactan and rhamnogalacturonan with several neutral sugar side chains ( ramified region of pectins). Both typical anti-complementary polysaccharides also reveal other pharmacological activities, and their immunopo-tentiating activities may somehow relate to the anti-complementary activity. 

Yamada H, Ohtani K, Kiyohara H, Cyong JC, Otsuka Y, Ueno Y, Omura S (1985) Purification and chemical properties of anti-complementary polysaccharide from the leaves of Artemisia princeps. Planta Medica 51 121-125... 

Yamada H, Otsuka Y, Omura S (1986) Structural characterization of anti-complementary polysaccharides from the leaves of Artemisia princeps PAMP. Planta Medica 52 311-314... 

The first paper on the bioactive polysaccharides from Glycyrrhiza uralensis roots was published in 1996 by Kiyohara et al. [57]. They isolated a pectic type polymer with anti-complementary and mitogenic activity that was an acidic pectin, possibly containing rhamnogalacturonan type I as part of the total structure. Degradation of the uronic acid part of the molecule decreased both types of bio activities. The neutral oligosaccharide chains were shown to retain some of the activities of the native polymer, but it was suggested that they should be attached to the acidic core to retain maximum activity. 

The leaves of large plantain Plantago major L.) are used for wotmd healing in the traditional medicine. The effect might be due to biologically active polysaccharides. A pectin, PMII with anti-complementary activity has been isolated from the leaves by water extraction and ion exchange chromatography (1). 

Pectic polysaccharide from roots of Glycyrrhiza uralensis Possible contribution of neutral oligosaccharide in the galacturonase resistant region to anti-complementary and mitogenic activities... 

Yamada, H., Ra, K.S., Kiyohara, H., Cyong, J.C. and Otsuka, Y. 1989. Structural characterisation of an anti-complementary pectic polysaccharide from the roots of Bupleurum falcatum L., Carbohydr. Res., 189 209-226. 

J.-F. Zhao, H. Kiyohara, H. Yamada, N. Takemoto, and H. Kawamura Heterogeneity and Characterization of Mitogenic and Anti-Complementary Pectic Polysaccharides from the Roots of Glycyrrhiza uralensis Fisch et D.C. Carbohyd. Res., 219, 149 (1991). 

Hirano, M., T. Matsumoto, H. Kiyohara, and H. Yamada Lipopolysaccharide-Independent Limulus Amebocyte Lysate Activating, Mitogenic and Anti-Complementary Activities of Pectic Polysaccharides from Chinese Herbs. Planta Med., 60, 248 (1994). 

Kiyohara, H., N. Takemoto, J.-F. Zhao, H. Kawamura, and H. Yamada Pectic Polysaccharides from Roots of Glycyrrhiza uralensis Possible Contribution of Neutral Oligosaccharides in the Galacturonase-Resistant Region to Anti-Complementary and Mitogenic Activities. Planta Med., 62, 14 (1996). 

Table 2 - Anti-complementary and related polysaccharides from medicinal herbs... 

LR-polysaccharide acidic heteroglycan > 500,000 anti-complementary activity Lithospermum euchromum Royle, roots 1986 [23]... 

GR-2lla pectic polysaccharides 190,000 -95,000 anti-complementary activity Clycyrrhiza uralensis Fisch. et DC., roots 1991 [43]... 

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