Complement-fixing Activity Research Articles

Bioactive polysaccharides in different plant parts of Aconitum carmichaelii.

Aconitum carmichaelii is an industrially cultivated medicinal plant in China and its lateral and mother roots are used in Traditional Chinese Medicine due to the presence of alkaloids. However, the rootlets and aerial parts are discarded after collection of the roots, and the non-toxic polysaccharides in this plant were less concerned than the alkaloids and poisonous features. In this study, five neutral and 14 acidic polysaccharide fractions were systematically isolated from different plant parts of A. carmichaelii, and their structural features and bioactivities were studied and compared. The neutral fraction isolated from the rootlets was different from those isolated from the lateral and mother roots, consisting of less starch and more possible mannans, galactans, and/or xyloglucans, which was similar to those of the aerial parts. Pectic polysaccharides containing homogalacturonan and branched type-I rhamnogalacturonan (RG-I) were present in all plant parts of A. carmichaelii. However, more arabinogalactan (AG)-II side chains in the RG-I backbone were present in the aerial parts, while more arabinans followed by AG-I/II were found in the roots. Various immunomodulatory effects determined by complement fixation activity and anti-inflammatory effects on intestinal epithelial cells IPEC-J2 of all polysaccharide fractions were observed. This study highlighted the diversity of polysaccharides present in A. carmichaelii, especially in the unutilized plant parts, and showed their potential medicinal values. This article is protected by copyright. All rights reserved.

The Adjuvant Activity of BCG Cell Wall Cytoskeleton on a Dengue Virus-2 Subunit Vaccine.

The uneven immunogenicity of the attenuated tetravalent dengue vaccine has made it difficult to achieve balanced protection against all four serotypes of the dengue virus (DENV). To overcome this problem, non-replicative vaccines have come into focus, as their immunogenicity is adjustable. This approach is excellent for multivalent vaccines but commonly faces the issue of low immunogenicity. In this present study, we developed a non-replicating dengue vaccine composed of UV-inactivated dengue virus-2 (UV-DENV-2) and DENV-2 NS1-279 protein encapsidated within nanoparticles. This vaccine candidate was administered in the presence of BCG cell wall cytoskeleton (BCG-CWS) as an adjuvant. We revealed, here, that encapsidated immunogens with BCG-CWS exerted potent activities on both B and T cells and elicited Th-1/Th-2 responses in mice. This was evidenced by BCG-CWS significantly augmenting antibody-mediated complement-fixing activity, strongly stimulating the antigen-specific polyfunctional T cell responses, and activating mixed Th-1/Th-2 responses specific to DENV-2- and NS1-279 antigens. In conclusion, BCG-CWS potently adjuvanted the inactivated DENV-2 and DENV subunit immunogens. The mechanism of adjuvanticity remains unclear. This study revealed the potential use of BCG-CWS in vaccine development.

Humoral Immune Responses to P. falciparum Circumsporozoite Protein (Pfcsp) Induced by the RTS, S Vaccine - Current Update.

Malaria vaccines targeting the circumsporozoite protein (CSP) of the P. falciparum parasite have been overall relatively promising. RTS, S is a pre-erythrocytic recombinant protein-based malaria vaccine that targets CSP. RTS, S effectiveness shows some limited success regardless of its 58% efficacy for severe disease. P. falciparum circumsporozoite protein (Pfcsp) has stood to be the main candidate protein for most pre-erythrocytic stage vaccines. Studies on the structural and biophysical characteristics of antibodies specific to CSP (anti-CSP) are underway to achieve fine specificity with the CSP polymorphic regions. More recent studies have proposed the use of different kinds of monoclonal antibodies, the use of appropriate adjuvants, ideal vaccination dose and frequency, and improved targeting of particular epitopes for the robust production of functional antibodies and high complement-fixing activity as other potential methods for achieving long-lasting RTS, S. This review highlights recent findings regarding humoral immune responses to CSP elicited by RTS, S vaccine.

Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali

Context Global studies on Argemone mexicana L. (Papaveraceae) traditionally used against malaria in Mali are limited to its low-mass compounds activities, and little information on its bioactive polysaccharides is available. Objective This study determines the structure and the immunomodulatory activity of polysaccharides from aerial parts of A. mexicana. Materials and methods Acidic polysaccharides from this plant material named HMAmA1 and HMAmA2 were isolated from water extracts. Their monosaccharide composition was determined by gas chromatography. Glycosidic linkages were determined using GC-MS. NMR was also applied. The polymers were tested for effects on the human complement system in vitro at different doses. Results The monosaccharide composition showed that the two polysaccharides contained in different amounts the following monomers: arabinose, rhamnose, galactose, and galacturonic acid. Overall structural analysis showed the presence of a low ratio of 1,2-linked rhamnose compared to 1,4-linked galacturonic acid with arabinogalactans substituted on position 4 of rhamnose. NMR data showed the presence of galacturonans alternated by rhamnogalacturonans bearing arabinose and galactose units. α-Linkages were found for l-arabinose, l-rhamnose and d-galacturonic acid, while β-linkages were found for d-galactose. The two polysaccharides exhibited strong complement fixation activities, with HMAmA1 being the highest potent fraction. ICH50 value of HMAmA1 was 5 µg/mL, compared to the control BPII being 15.9 µg/mL. Discussion and conclusions Polysaccharides form A. mexicana presented a complement fixation effect. The complement system is an important part of the immune defense, and compounds acting on the cascade are of interest. Therefore, these polymers may be useful as immunodulatory agents.

Naturally induced humoral response against Plasmodium vivax reticulocyte binding protein 2P1

BackgroundPlasmodium vivax is the most prevalent malaria parasite in many countries. A better understanding of human immunity to this parasite can provide new insights for vaccine development. Plasmodium vivax Reticulocyte Binding Proteins (RBPs) are key parasite proteins that interact with human proteins during erythrocyte invasion and are targets of the human immune response. The aim of this study is to characterize the human antibody response to RBP2P1, the most recently described member of the RBP family.MethodsThe levels of total IgG and IgM against RBP2P1 were measured using plasmas from 68 P. vivax malaria patients and 525 villagers in a malarious village of western Thailand. The latter group comprises asymptomatic carriers and healthy uninfected individuals. Subsets of plasma samples were evaluated for anti-RBP2P1 IgG subtypes and complement-fixing activity.ResultsAs age increased, it was found that the level of anti-RBP2P1 IgG increased while the level of IgM decreased. The main anti-RBP2P1 IgG subtypes were IgG1 and IgG3. The IgG3-seropositive rate was higher in asymptomatic carriers than in patients. The higher level of IgG3 was correlated with higher in vitro RBP2P1-mediated complement fixing activity.ConclusionsIn natural infection, the primary IgG response to RBP2P1 was IgG1 and IgG3. The predominance of these cytophilic subtypes and the elevated level of IgG3 correlating with complement fixing activity, suggest a possible role of anti-RBP2P1 antibodies in immunity against P. vivax.

English

Medicinal plants used against malaria in Mali have previously been tested for their antiplasmodial activities using their organic solvent and water extracts. As the healers mainly use the water extracts for their treatments of malaria-patients, our aim was to study the water-soluble components from Malian plants used for treatment of malaria. Argemone mexicana (aerial parts), Sarcocephalus latifolius (root bark), Vitex doniana (leaves), and Malarial-5® (an improved traditional medicine (ITM) in tea) were the objects of our studies. Water extracts of these plants contained primarily polysaccharides. Due to this, the studies focused on the determination of the monosaccharide composition of the polymers present as well as assessing the immunomodulatory properties of the polysaccharide fractions isolated from these plants. Each plant material was extracted sequentially with dichloromethane, 80% ethanol and water at 100°C. The polysaccharides were obtained using gel filtration of the aqueous extracts and their monosaccharide compositions were determined using gas chromatography. Immunomodulatory effects were assessed using the complement fixation test and macrophage stimulation. All aqueous extracts from the four samples contained polysaccharides. The monosaccharide compositions vary between the plants. Arabinose, rhamnose, galactose, glucose and galacturonic acid were present in all samples, glucose being the main monomer. These polysaccharides showed complement fixing activity and induced nitrite oxide release from macrophages in a dose dependent manner. The polysaccharide fractions of A. mexicana (Am1) and V. doniana (Vd1) showed the most potent activities. These two fractions had an ICH50 of 2.4 and 6.3 μg/mL respectively in the complement fixation assay. The same two fractions induced a dose dependent release of nitrite oxide from macrophages. The results demonstrated that antimalarial plants contain polysaccharides with immunomodulatory properties. This preliminary work constitutes a new approach of antimalarial studies. Key words: Polysaccharides, immunomodulatory effects, antimalarial plants, Mali. &nbsp

Antioxidant, immunomodulatory, oxidative stress inhibitory and iron supplementation effect of Astragalus membranaceus polysaccharide-iron (III) complex on iron-deficiency anemia mouse model.

As iron supplement, the antioxidant activities of APS-iron (III) complex were comprehensively evaluated by 5-axe cobweb charts, which indicated the APS-iron (III) complex had a certain antioxidant activity and been weaker than that of APS. The results of immunological activity experiments indicated the stimulation index increased with APS-iron (III) complex concentration increase. When the concentration of the APS-iron (III) complex was 50 μg/mL, the lymphocytes proliferation increased by 35.7% compared with APS. APS-iron (III) complex also had better complement fixing activity than APS, 0.589 mg/mL of which achieved 50% complement fixing activities. Through the iron supplement experiments on iron-deficiency anemia mouse model, we found the APS-iron (III) complex faster increased hemoglobin concentration, SOD, CAT and faster decreased MDA to the normal level than Niferex and ferrous sulfate. Histological results revealed that the tissue sections were clear without obvious pathological changes and bone marrow had most hematopoietic cells from APS-iron (III) complex rat group, which also proved the APS-iron (III) complex had no significant side effects. Therefore, APS-iron (III) complex may be developed as a multifunctional iron supplement for clinical application.

Antibody-mediated rejection after liver transplantation-relevance of C1q and C3d-binding antibodies.

The aim of our study was to evaluate the relevance of complement-binding donor-specific antibodies (DSA) for prediction of antibody-mediated rejection (AMR) after liver transplantation. Sera from 123 liver transplant recipients were retrospectively defined for HLA specificity and complement-fixing activity using the single antigen beads, C1q and C3d techniques. Liver-recipients' sera were tested before transplantation, 3, 6 months and 1 year after transplantation. Patients were followed up for graft survival and rejection incidence for 1 year after transplantation. All patients with pretransplant complement-binding DSA developed severe AMR after transplantation, while three recipients out of four, who produced de novo complement-fixing DSA, developed AMR. Definition of DSA with respect to complement-fixing activity may provide clinically relevant information about the risk of AMR after liver transplantation.

The Complement System Contributes to Functional Antibody-Mediated Responses Induced by Immunization with Plasmodium falciparum Malaria Sporozoites.

ABSTRACTLong-lasting and sterile homologous protection against malaria can be achieved by the exposure of malaria-naive volunteers under chemoprophylaxis to Plasmodium falciparum-infected mosquitoes (chemoprophylaxis and sporozoite [CPS] immunization). While CPS-induced antibodies neutralize sporozoite infectivity in vitro and in vivo, antibody-mediated effector mechanisms are still poorly understood. Here, we investigated whether complement contributes to CPS-induced preerythrocytic immunity. Sera collected before and after CPS immunization in the presence of active or inactive complement were assessed for the recognition of homologous NF54 and heterologous NF135.C10 sporozoites, complement fixation, sporozoite lysis, and possible subsequent effects on in vitro sporozoite infectivity in human hepatocytes. CPS immunization induced sporozoite-specific IgM (P < 0.0001) and IgG (P = 0.001) antibodies with complement-fixing capacities (P < 0.0001). Sporozoite lysis (P = 0.017), traversal (P < 0.0001), and hepatocyte invasion inhibition (P < 0.0001) by CPS-induced antibodies were strongly enhanced in the presence of active complement. Complement-mediated invasion inhibition in the presence of CPS-induced antibodies negatively correlated with cumulative parasitemia during CPS immunizations (P = 0.013). While IgG antibodies similarly recognized homologous and heterologous sporozoites, IgM binding to heterologous sporozoites was reduced (P = 0.023). Although CPS-induced antibodies did not differ in their abilities to fix complement, lyse sporozoites, or inhibit the traversal of homologous and heterologous sporozoites, heterologous sporozoite invasion was more strongly inhibited in the presence of active complement (P = 0.008). These findings demonstrate that CPS-induced antibodies have complement-fixing activity, thereby significantly further enhancing the functional inhibition of homologous and heterologous sporozoite infectivity in vitro. The combined data highlight the importance of complement as an additional immune effector mechanism in preerythrocytic immunity after whole-parasite immunization against Plasmodium falciparum malaria.

Two complement fixing pectic polysaccharides from pedicel of Lycium barbarum L. promote cellular antioxidant defense

Purification, characterization and biological activities of polysaccharides from Lycium barbarum pedicel were investigated in this study. Two polysaccharides, PLBP-I-I and PLBP-II-I, were obtained from water extracts by anion exchange chromatography and gel filtration. Structural elucidation based on IR, 1H NMR, and 13C NMR spectra indicated that these two fractions were typical pectic polysaccharides, with homogalacturonan and rhamnogalacturonan type I regions and arabinogalactan side chains, and some of the galacturonic acid units were methyl esterified. Both fractions exhibited potent complement fixating activity and pro-antioxidant defense capacity, and those two fractions showed different activities. The higher complement fixation activity was obtained in fraction PLBP-I-I, while the higher pro-antioxidant defense capacity was obtained in fraction PLBP-II-I, which may be due to the structural differences between those two fractions. Thus, the pedicel of L. barbarum could be used as a potential source for natural immunomodulator and antioxidant.

A novel iron supplements preparation from Grifola frondosa polysaccharide and assessment of antioxidant, lymphocyte proliferation and complement fixing activities

Grifola frondosa polysaccharide-iron (III) complex (GFP-iron) was synthesized and characterized. Based on single factor and orthogonal optimization experiments of GFP-iron (III) complex synthesis, the optimum conditions were the reaction temperature 80°C, pH 8, reaction time 90min and ratio of catalyst to GFP 1:1.0gg−1. The iron content of GFP-iron (III) complex reached 24.15% under the optimums and characterized by fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-Ray Diffraction (XRD), thermogravimetry (TG) and iron release in vitro assay.By 5-axe cobweb charts, the antioxidant activity of GFP-iron (III) complex was comprehensively evaluated. The results showed GFP-iron (III) complex retained a certain antioxidant activity. The lymphocytes proliferation of GFP-iron (III) complex was increased by 61.68% comparing with that of GFP at the sample concentration of 62.5μg/mL. At giving 50% haemolysis, the concentration of GFP-iron (III) complex was 0.261mg/mL. Therefore, GFP-iron (III) complex would be expected to exploit into a new-type comprehensive iron supplements.

Tilia tomentosa pectins exhibit dual mode of action on phagocytes as β-glucuronic acid monomers are abundant in their rhamnogalacturonans I

Silver linden flowers contain different pectins (PSI-PSIII) with immunomodulating properties. PSI is a low-esterified pectic polysaccharide with predominant homogalacturonan region, followed by rhamnogalacturonan I (RGI) with arabinogalactan II and RGII (traces) domains. PSII and PSIII are unusual glucuronidated RGI polymers. PSIII is a unique high molecular weight RGI, having almost completely O-3 glucuronidated GalA units with >30% O-3 acetylation at the Rha units. Linden pectins induced reactive oxygen species (ROS) and NO generation from non-stimulated whole blood phagocytes and macrophages, resp., but suppressed OZP-(opsonized zymosan particles)-activated ROS generation, LPS-induced iNOS expression and NO production. This dual mode of action suggests their anti-inflammatory activity, which is known for silver linden extracts. PSI expressed the highest complement fixation and macrophage-stimulating activities and was active on intestinal Peyer’s patch cells. PSIII was active on non-stimulated neutrophils, as it induced ß2-integrin expression, revealing that acetylated and highly glucuronidated RGI exhibits immunomodulating properties via phagocytes.

The common lavender (Lavandula angustifolia Mill.) pectic polysaccharides modulate phagocytic leukocytes and intestinal Peyer’s patch cells

Two pectic (chPS-L1, chPS-L2) and one polyphenolic (chPP-L) fractions were obtained from lavender flowers after boiling water extraction, exhaustive removing of alcohol-soluble molecules and SEC. chPS-L1 (52.4kDa) contains mainly low-acetylated and high-methoxylated homogalacturonans (HG), and smaller rhamnogalacturonan (RG) I backbone fragments rich in 1,3,5-branched arabinan and arabinogalactan (AG) II side chains. chPS-L2 (21.8kDa) contains predominantly similarly esterified HG, followed by RGI with AGII structures and RGII. The prevalence of catechin and epicatechin in chPP-L indicates that they form weak interactions with pectins. chPS-L1 and chPS-L2 enhanced ß2-integrin expression on neutrophils, inducing ROS generation and macrophage NO production. Both the effects on ß2-integrin and high complement fixation activity of chPS-L1 were proposed for its inhibitory action against PMA- and OZP-activated ROS formation. This, together with suppression of NO generation after co-stimulation with chPS-L1 and LPS, suggested anti-inflammatory activity of studied pectins. Lavender polysaccharides expressed intestinal Peyer’s patch immunomodulating activity.

Purification, characterization, and complement fixation activity of acidic polysaccharides from Tuber sinoaestivum

Tuber sinoaestivum, Chinese black truffle, which is very commercially important in China, is not only well known for its delicious taste but also for its high medical value. Polysaccharides from its European sister species Tuber aestivum have been shown to have some interesting bioactivities, but very few studies have been performed on it. In this study, 2 acidic polysaccharides, T. sinoaestivum polysaccharide-I (TSP-I) and T. sinoaestivum polysaccharide-II (TSP-II), were obtained from 100 °C water extracts of T. sinoaestivum fruiting bodies by diethylaminoethyl (DEAE) anion exchange chromatography and gel filtration. The polysaccharides presented similar monosaccharide composition, molecular size, and types of linkage. The results from methylation, Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) indicated the polysaccharides as the rhamno-mannan-like types that also contain mannuronic acid and acetyl groups. Both of TSP-I and TSP-II exhibited potential complement fixation activity. The higher molecular weight and lower amount of glucose in TSP-II may explain why it had higher complement fixation activity. Accordingly, the Chinese truffle T. sinoaestivum might serve as a potential immunomodulator.

Polysaccharides with immunomodulating activity from roots of Gentiana crassicaulis

Two polysaccharides, GCP-I-I and GCP-II-I, were obtained from 100°C water extracts of Gentiana crassicaulis roots by DEAE anion exchange chromatography and gel filtration. The results from methanolysis, methylation, FT-IR and NMR, indicated that these two fractions are typical pectic polysaccharides, with HG and RG-I regions and AG-I/AG-II side chains, and some of the galacturonic acid units of fraction GCP-I-I were methyl esterified. Fractions GCP-I-I and GCP-II-I, both exhibited potent complement fixation, and fraction GCP-I-I was more potent than positive control BPII. The higher complement fixation activity obtained in fraction GCP-I-I may be due to the higher Mw and/or higher amount of AG-II present in fraction GCP-I-I than fraction GCP-II-I. The polysaccharides from G. crassicaulis could be used as a potential natural immunomodulator.

Purification and Partial Structural Characterization of a Complement Fixating Polysaccharide from Rhizomes of Ligusticum chuanxiong.

Rhizome of Ligusticum chuanxiong is an effective medical plant, which has been extensively applied for centuries in migraine and cardiovascular diseases treatment in China. Polysaccharides from this plant have been shown to have interesting bioactivities, but previous studies have only been performed on the neutral polysaccharides. In this study, LCP-I-I, a pectic polysaccharide fraction, was obtained from the 100 °C water extracts of L. chuangxiong rhizomes and purified by diethylaminethyl (DEAE) sepharose anion exchange chromatography and gel filtration. Monosaccharide analysis and linkage determination in addition to Fourier transform infrared (FT-IR) spectrometer and Nuclear magnetic resonance (NMR) spectrum, indicated that LCP-I-I is a typical pectic polysaccharide, with homo-galacturonan and rhamnogalacturonan type I regions and arabinogalactan type I and type II (AG-I/AG-II) side chains. LCP-I-I exhibited potent complement fixation activity, ICH50 of 26.3 ± 2.2 µg/mL, and thus has potential as a natural immunomodulator.

RG-I regions from elderflower pectins substituted on GalA are strong immunomodulators

Sambuci flos, also known as elderflower, has traditionally been used and is still in use for treatment of various types of illnesses related to the immune system such as cold, flu, fever and inflammation. Pectic polysaccharides from 50% EtOH, 50°C water and 100°C water extracts from elderflowers were treated with endo-α-d-(1–4)-polygalacturonase after previous de-esterification with the intention of isolating hairy regions and relate variation in structure to immunomodulating activity. High molecular weight sub-fractions (25–29kDa) and medium molecular weight sub-fractions (6–17kDa) were isolated after enzymatic treatment in addition to oligogalacturonides. Structural elucidation indicated that RG-I regions with AG-I and AG-II sidechains were the predominant structures in the high molecular weight sub-fractions, and two of three 1,4-linked GalA units in the rhamnogalacturonan backbone were branched in either position 2 or 3. The medium molecular weight sub-fractions had monomers and linkages typical for both RG-I and RG-II. The results showed that the high molecular RG-I containing polymers exhibit the highest dose-dependent complement fixing and macrophage stimulating activities.

Detection of Post-Transplant Anti-HLA Donor-Specific Antibodies through the Use of Stored Donors’ Cell Lysates and Solid Phase-Based Cross-Matching

Transplant recipients who have sensitizing events such as pregnancies, blood transfusions and previous transplants often develop antibodies directed against human leukocyte antigen (HLA)-molecules of the donors’ organs. These pre-formed donor-specific antibodies (DSA) represent a high risk of organ failure as a consequence of antibody-mediated hyper-acute or acute allograft rejection. In order to select recipients without donor-specific anti- HLA antibodies the complement-dependent cytotoxicity crossmatch assay (CDC-CM) was established as standard procedure more than forty years ago. This assay, however, is characterized by several drawbacks such as a high degree of vitality (at least 90%) required for the target lymphocytes of a given donor. This requirement highly limits its applicability for patients treated with therapeutic antibodies, special drugs or patients who suffer from underlying diseases i.e., especially from type III (immune complex) auto-immune diseases. Furthermore, only DSA which exert complement-fixing activity are detected. As a consequence novel crossmatch procedures which act independently of the complement system and which do not represent functional assays have been generated in the format of flow cytometry (FACS-) or solid phase (ELISA-) assays. Especially solid phase-based assays the outcomes of which are not limited by insufficient cell vitalities have in spite of various environmental disruptive factors been shown to lead to valid results and not to false positive outcomes in contrast to CDC-based cross-matching. Our current results show the superiority of ELISA-based cross-matching in a novel context. Data are provided which show the ELISA-based applicability of long term-stored donors’ materials to demonstrate or exclude the involvement of DSA in a rejection episode by de facto cross-matching and not only by the virtual crossmatch approach i.e., the comparison of the recipients’ anti-HLA antibody specificities with the donors’ historically identified HLA-pheno- and/or genotypes.

Questioning the added value of Luminex single antigen beads to detect C1q binding donor HLA-specific antibodies.

Luminex single antigen bead (SAB) technology enables highly sensitive and rapid characterization of immunoglobulin G (IgG) human leukocyte antigen (HLA)-specific antibodies. It is widely used to determine antibody compatibility for renal transplantation and to aid the diagnosis of antibody-mediated rejection and response to therapy. HLA-specific antibodies may contribute to allograft rejection through a variety of mechanisms, including activation of the classical complement pathway, endothelial cell activation, and recruitment of Fc-dependent effector cells. Of these, complement-mediated cytotoxicity has long been associated with hyperacute rejection and, more recently, antibody-mediated rejection for which the deposition of the complement component C4d on peritubular capillaries is a diagnostic marker. In the standard SAB assay, patient serum is incubated with microbeads coated with purified HLA proteins. Human leukocyte antigenYspecific IgG antibody binding is then detected using a fluorescent anti-IgG detection antibody. Increasing levels of donor HLA-specific antibodies detected by this assay predict inferior long-term graft outcome, but not all patients with IgG donor-specific HLA antibodies (DSA) have a poor graft outcome (1, 2). This observation is consistent with the notion that HLA antibodies with the same specificity may differ in their ability to cause graft injury, and this variability may be related to differences in complement fixing activity. In an effort to improve the clinical utility of the IgG

Structural features and complement fixing activity of polysaccharides from Codonopsis pilosula Nannf. var. modesta L.T.Shen roots

Two pectic polysaccharides, 50WCP-II-I and 100WCP-II-I, were obtained from 50 and 100°C water extracts of Codonopsis pilosula roots by ion exchange chromatography and gel filtration. The study of the sub-fractions obtained after pectinase degradation showed that the complement fixation activities of these pectins are expressed mainly by their ramified regions. The structure studies of native and sub-fractions showed the 50WCP-II-I is a pectic polysaccharide, with long homogalacturonan regions (some of the galacturonic acid units were methyl esterified), interrupted by one short rhamnogalacturonan I (RG-I) region. The side chains of the RG-I region are arabinogalactan type I (AG-I) and type II (AG-II) attached on position 4 of rhamnose. The 100WCP-II-I has two main ramified regions, one is galacturonan region with AG-I side chain on position 2 of GalA, and the other one is RG-I region with AG-II side chain on position 4 of Rha.