Structural characterization of rhamnogalacturonan domains from Panax ginseng C. A. Meyer

Polysaccharides in fruits: Biological activities, structures, and structure-activity relationships and influencing factors-A review

Fruits are a rich source of polysaccharides, and an increasing number of studies have shown that polysaccharides from fruits have a wide range of biological functions. Here, we thoroughly review recent advances in the study of the bioactivities, structures, and structure-activity relationships of fruit polysaccharides, especially highlighting the structure-activity influencing factors such as extraction methods and chemical modifications. Different extraction methods cause differences in the primary structures of polysaccharides, which in turn lead to different polysaccharide biological activities. Differences in the degree of modification, molecular weight, substitution position, and chain conformation caused by chemical modification can all affect the biological activities of fruit polysaccharides. Furthermore, we summarize the applications of fruit polysaccharides in the fields of pharmacy and medicine, foods, cosmetics, and materials. The challenges and perspectives for fruit polysaccharide research are also discussed.

Fractionation of cassava pectins and their detailed structural analyses using various pectinolytic enzymes

In this study, we analyzed the pectin structure within the pulp of cassava. Cassava pectin, derived from cassava pulp treatment at 120 °C for 90 min, was separated into four fractions (CP-P, CP-SD1, CP-SD2F, and CP-SD2R) based on variations in water solubility, electrical properties, and molecular weights. Sugar composition analysis demonstrated an abundance of homogalacturonan (HG) in CP-P and CP-SD2F, rhamnogalacturonan I (RG-I) in CP-SD2R, and neutral sugars in CP-SD1. Because RG-I possesses a complex structure, we analyzed CP-SD2R using various pectinolytic enzymes. Galactose was the major sugar in CP-SD2R accounting for 49 %, of which 65 % originated from arabinogalactan I, 9 % from galactose and galactooligosaccharides, 5 % from arabinogalactan II, and 11 % from galactoarabinan. Seventy-four percent of arabinose in CP-SD2R was present as galactoarabinan. The methylation (DM) and acetylation (DAc) degrees of cassava pectin were 11 and 15 %, respectively. The HG and RG-I regions exhibited DAc values of 5 and 44 %, respectively, signifying the high DAc of RG-I compared to HG. Information derived from the structural analysis of cassava pectin will enable efficient degradation of pectin and cellulose, leading to the use of cassava pulp as a raw material for biorefineries.

Role of acemannan and pectic polysaccharides in saline-water stress tolerance of Aloe vera (Aloe barbadensis Miller) plant

This study investigates the impact of water and salinity stress on Aloe vera, focusing on the role of Aloe vera polysaccharides in mitigating these stresses. Pectins and acemannan were the most affected polymers. Low soil moisture and high salinity (NaCl 80 mM) increased pectic substances, altering rhamnogalacturonan type I in Aloe vera gel. Aloe vera pectins maintained a consistent 60 % methyl-esterification regardless of conditions. Interestingly, acemannan content rose with salinity, particularly under low moisture, accompanied by 90 to 150 % acetylation increase. These changes improved the functionality of Aloe vera polysaccharides: pectins increased cell wall reinforcement and interactions, while highly acetylated acemannan retained water for sustained plant functions. This study highlights the crucial role of Aloe vera polysaccharides in enhancing plant resilience to water and salinity stress, leading to improved functional properties.

Ginseng-derived type I rhamnogalacturonan polysaccharide binds to galectin-8 and antagonizes its function

Background

Panax ginseng Meyer polysaccharides exhibit various biological functions, like antagonizing galectin-3-mediated cell adhesion and migration. Galectin-8 (Gal-8), with its linker-joined N- and C-terminal carbohydrate recognition domains (CRDs), is also crucial to these biological processes, and thus plays a role in various pathological disorders. Yet the effect of ginseng-derived polysaccharides in modulating Gal-8 function has remained unclear.

Methods

P. ginseng-derived pectin was chromatographically isolated and enzymatically digested to obtain a series of polysaccharides. Biolayer Interferometry (BLI) quantified their binding affinity to Gal-8, and their inhibitory effects on Gal-8 was assessed by hemagglutination, cell migration and T-cell apoptosis.

Results

Our ginseng-derived pectin polysaccharides consist mostly of rhamnogalacturonan-I (RG-I) and homogalacturonan (HG). BLI shows that Gal-8 binding rests primarily in RG-I and its β-1,4-galactan side chains, with sub-micromolar KD values. Both N- and C-terminal Gal-8 CRDs bind RG-I, with binding correlated with Gal-8-mediated function.

Conclusion

P. ginseng RG-I pectin β-1,4-galactan side chains are crucial to binding Gal-8 and antagonizing its function. This study enhances our understanding of galectin-sugar interactions, information that may be used in the development of pharmaceutical agents targeting Gal-8.

Identification of intracellular activation mechanism of rhamnogalacturonan-I type polysaccharide purified from Panax ginseng leaves in macrophages and roles of component sugar chains on activity

This study aimed to investigate the mechanisms underlying intracellular signaling pathways in macrophages in relation to the structural features of rhamnogalacturonan (RG) I-type polysaccharide (PGEP-I) purified from Panax ginseng leaves. For this investigation, we used several specific inhibitors and antibodies against mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-κB), and pattern recognition receptors (PRRs). Furthermore, we investigated the roles of component sugar chains on immunostimulating activity through a sequential enzymatic and chemical degradation steps. We found that PGEP-I effectively induced the phosphorylation of several MAPK- and NF-κB-related proteins, such as p38, cJun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p65. Particularly, immunocytochemistry analysis confirmed the PGEP-I-induced translocation of p65 into the nucleus. Furthermore, the breakdown of PGEP-I side chains and main chain during sequential enzymatic and chemical degradation reduced the PGEP-I-induced macrophage cytokine secretion activity. IL-6, TNF-α, and NO secreted by macrophages are associated with several signaling pathway proteins such as ERK, JNK, and NF-κB and several PRRs such as dectin-1, CD11b, CD14, TLR2, TLR4, and SR. Thus, these findings suggest that PGEP-I exerts potent macrophage-activating effects, which can be attributed to its typical RG-I structure comprising arabinan, type II arabinogalactan, and rhamnose-galacturonic acid repeating units in the main chain.

Structural characterization and anti-oxidation activity of pectic polysaccharides from Swertia mileensis

In this study, we isolated the pectic polysaccharide WSMP-A2b (37 kDa) from the stems and leaves of Swertia mileensis, and we investigated its compositional/structural features and antioxidant activity. FT-IR, NMR, monosaccharide composition, enzymatic hydrolysis and methylation analyses indicated that WSMP-A2b is composed of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains with mass ratios of 2.1:1.0:2.2. The RG-I domain is primarily substituted with α-L-1,5-arabinan and type II arabinogalactan (AG-II) side chains, as well as minor contributions of β-D-1,4-galactan and/or type I arabinogalactan (AG-I) side chains. The HG domain was released in the form of un-esterified and partly methyl-esterified and/or acetyl-esterified oligogalacturonides with a 1 to 7 degree of polymerization after endo-polygalacturonase degradation. WSMP-A2b showed stronger antioxidant activity in vitro, in part this might due to the presence of galacturonic acid (GalA). In addition, WSMP-A2b exerted a protective effect on tert-butyl hydroperoxide (tBHP)-induced oxidative stress in INS-1 cells by reducing reactive oxygen species (ROS) production and increasing the glutathione/oxidized glutathione (GSH/GSSG) ratio. Our results provide crucial structural information on this pectic polysaccharide from Swertia mileensis, thus prompting further investigation into its structure-activity relationship.

Elucidating structure of pectin in ramie fiber to customize enzyme cocktail for high-efficiency enzymatic degumming

Pectin is one of the main components of bast fiber including ramie fiber, and must be removed before use. Enzymatic degumming is the preferred process as it is an environment-friendly, simple and controllable process for ramie degumming. However, an important problem limiting wide application of this process is the high cost due to the low efficiency of enzymatic degumming. In this study, pectin samples were extracted from raw ramie fiber and degummed ramie fiber, respectively, and their structures were characterized and compared to allow tailoring of an enzyme cocktail for degrading the pectin. It was elucidated that pectin from ramie fiber is composed of low esterified homogalacturonan (HG) and low branched rhamnogalacturonan I (RG-I), and the ratio of HG/RG-I is 1.72:1. Based on the pectin structure, potential enzymes to be used for enzymatic degumming of ramie fiber were proposed and an enzyme cocktail was customized. Degumming experiments confirmed that the customized enzyme cocktail can effectively remove pectin from ramie fiber. To our knowledge, this is the first time the structural characteristics of pectin in ramie fiber have been clarified, and it also provides an example of tailoring a specific enzyme system to achieve high-efficiency degumming for biomass containing pectin.

A ginseng-derived rhamnogalacturonan I (RG-I) pectin promotes longevity via TOR signalling in Caenorhabditis elegans

Panax ginseng C. A. Meyer (ginseng), a traditional Chinese herb, is usually used to improve health and increase anti-aging activity for human. Polysaccharides are bioactive components of ginseng. Herein, using Caenorhabditis elegans as a model, we discovered a ginseng-derived rhamnogalacturonan I (RG-I) pectin WGPA-1-RG promoted longevity via TOR signalling pathway with transcription factors FOXO/DAF-16 and Nrf2/SKN-1 accumulated in the nucleus, where they activated target genes. And the WGPA-1-RG-mediated lifespan extension was dependent on endocytosis, rather than a bacterial metabolic process. Glycosidic linkage analyses combined with arabinose- and galactose-releasing enzyme hydrolyses identified the RG-I backbone of WGPA-1-RG was primarily substituted with α-1,5-linked arabinan, β-1,4-linked galactan and arabinogalactan II (AG-II) side chains. Feeding worms with the WGPA-1-RG-derived fractions which lost distinct structural elements by enzymatic digestions, we found the arabinan side chains prominently contributed to the longevity-promoting activity of WGPA-1-RG. These findings provide a novel ginseng-derived nutrient that potentially increases human longevity.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2020. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.

An Overview of Antitumour Activity of Polysaccharides

Cancer incidence and mortality are rapidly increasing worldwide; therefore, effective therapies are required in the current scenario of increasing cancer cases. Polysaccharides are a family of natural polymers that hold unique physicochemical and biological properties, and they have become the focus of current antitumour drug research owing to their significant antitumour effects. In addition to the direct antitumour activity of some natural polysaccharides, their structures offer versatility in synthesizing multifunctional nanocomposites, which could be chemically modified to achieve high stability and bioavailability for delivering therapeutics into tumor tissues. This review aims to highlight recent advances in natural polysaccharides and polysaccharide-based nanomedicines for cancer therapy.

Enzymatic fingerprinting reveals specific xyloglucan and pectin signatures in the cell wall purified with primary plasmodesmata

Plasmodesmata (PD) pores connect neighbouring plant cells and enable direct transport across the cell wall. Understanding the molecular composition of these structures is essential to address their formation and later dynamic regulation. Here we provide a biochemical characterisation of the cell wall co-purified with primary PD of Arabidopsis thaliana cell cultures. To achieve this result we combined subcellular fractionation, polysaccharide analyses and enzymatic fingerprinting approaches. Relative to the rest of the cell wall, specific patterns were observed in the PD fraction. Most xyloglucans, although possibly not abundant as a group, were fucosylated. Homogalacturonans displayed short methylated stretches while rhamnogalacturonan I species were remarkably abundant. Full rhamnogalacturonan II forms, highly methyl-acetylated, were also present. We additionally showed that these domains, compared to the broad wall, are less affected by wall modifying activities during a time interval of days. Overall, the protocol and the data presented here open new opportunities for the study of wall polysaccharides associated with PD.

Structural characterization and anti-oxidation activity evaluation of pectin from Lonicera japonica Thunb

Pectins are nutrient components of plants and are widely used in the food industry. In this study, one major pectin fraction (WLJP-A0.2b) with Mw of 40.6 kDa was purified from Lonicera japonica Thunb. The structural feature and antioxidant activity of it was investigated. Monosaccharide composition, Fourier transform infrared (FT-IR) spectra, enzymatic hydrolysis, and nuclear magnetic resonance (NMR) spectra analysis indicated that WLJP-A0.2b consisted of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II), and homogalacturonan (HG) domains, with mass ratio of 0.4:1.0:2.1. The RG-I domain contained highly branched α-L-1,5-arabinan, β-D-1,4-galactan and type II arabinogalactan (AG-II) side chains. The HG domain was released in the form of un-esterified and partly methyl-esterified and/or acetyl-esterified oligogalacturonides with degree of polymerization 1–8 after degradation by endo-polygalacturonase. Radical scavenging assays indicated that WLJP-A0.2b exhibited antioxidant activity through the synergistic effects of different pectin domains. Oligogalacturonides, especially de-esterified oligogalacturonides, showed better antioxidant activities than RG-II and RG-I domains. Moreover, de-esterified oligogalacturonides remarkably reduced H₂O₂-induced reactive oxygen species production in HEK-293T cells. These results provide useful information for screening of natural antioxidants from Lonicera japonica Thunb. and application of pectin in functional food field.

Comparative study of water-soluble polysaccharides isolated from leaves and roots of Isatis indigotica Fort

Water-soluble polysaccharides were isolated from the leaves and roots of Isatis indigotica Fort., and their structural features were studied and compared. One neutral polysaccharide fraction (WFIP-N) and three pectin fractions (WFIP-A-A, WFIP-A-B and WFIP-A-C) were obtained from the leaves, and one neutral polysaccharide fraction (WRIP-N) and two pectin fractions (WRIP-A-A and WRIP-A-B) were obtained from the roots. WFIP-A-B (Mw = 34.6 kDa) and WRIP-A-B (Mw = 29.9 kDa) were the major pectic polysaccharides. Monosaccharide composition, FT-IR, enzymatic hydrolysis, NMR and methylation analysis indicated that both WFIP-A-B and WRIP-A-B are composed of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains with mass ratios of 1.5:1.0:0.4 and 0.3:1.0:1.7, respectively. WFIP-A-B and WRIP-A-B were found to be rich in RG-I and HG domains, respectively, and mainly contained type II arabinogalactan (AG-II) and α-L-1,5-arabinan side chains, but those in WRIP-A-B were more numerous and longer. Our results provide structural features and differences between these polysaccharides which will help to elucidate their functional differences.

Ginseng, Tribulus Extracts and Pollen Grains Supplementation Improves Sexual State, Testes Redox Status, and Testicular Histology in Nile Tilapia Males

This study aimed to investigate the effect of dietary supplementation of three natural antioxidants on sex hormone levels, enzymatic and non-enzymatic antioxidant systems, and histological changes in the testes of male Nile tilapia, Oreochromis niloticus. A total of 210 male Nile tilapia were distributed into seven treatments (three replicates for each) with an initial weight of 3.67 g fish⁻¹. The fish were fed experimental diets (32% crude protein) without supplementation as control or supplemented with ginseng extract (GE; 0.2 and 0.4 g GE kg⁻¹ diet), Tribulus terrestris extract (TT; 0.6 and 1.2 g TT kg⁻¹ diet), and date palm pollen grains (DPPG; 3 and 6 g DPPG kg⁻¹ diet) for 84 days. The results revealed a significant increase in the luteinizing hormone level with TT, DPPG, and GE supplementation increased the levels by 22.9%, 18.5%, and 17.6%, respectively. The testosterone level also increased significantly with TT_1.2, GE_0.4, TT_0.6, and DPPG₆ by 86.23%, 64.49%, 57.40%, and 24.62%, respectively. The antioxidant status in the testis homogenate showed a significant decrease in the level of thiobarbituric acid-reactive substances when using different dietary substances. In addition, glutathione reduced contents, glutathione S-transferases, glutathione peroxidase, catalase, and superoxide dismutase activities significantly increased with different dietary supplementation in a dose-dependent manner. The histological evaluation revealed normal histological features of the testes in all treatments with increasing active seminiferous tubules (%) in GE, TT, and DPPG supplemented groups, especially with the highest levels. In conclusion, the dietary supplementation of GE, TT, and DPPG enhanced sex hormones level, redox status, and testis structure and could improve the male reproductive performance of Nile tilapia.

Structural features and anticancer mechanisms of pectic polysaccharides: A review

The anticancer activity of pectic polysaccharides (PPs) was proved by numerous studies, and which also indicated that the bioactivity of PPs was closely related to its complicated structures. Based on the summary and analysis about structure characteristics and corresponding enzymatic process of the reported PPs, the anticancer mechanism and related structural features were systematically clarified. It was found that not only the direct effects on the cancer cells by proliferation inhibition or apoptosis, but also the regulation of immune system, gut microbiota and gut metabolism as indirect effects, jointly played important roles in the anticancer of PPs. Nevertheless, during the study of PPs as promising anticancer components, the exact structure-function relationship, digestion process in vivo, and comprehensive action mechanism are still not well understanding. With the unveiling of the proposed issues, it is believed that PPs are promising to be exploited as effective cancer therapy/adjunctive therapy drugs or functional foods.

Structure and functionality of Rhamnogalacturonan I in the cell wall and in solution: A review

Rhamnogalacturonan I (RG-I) belongs to the pectin family and is found in many plant cell wall types at different growth stages. It plays a significant role in cell wall and plant biomechanics and shows a gelling ability in solution. However, it has a significantly more complicated structure than smooth homogalacturonan (HG) and its variability due to plant source and physiological state contributes to the fact that RG-I's structure and function is still not so well known. Since functionality is a product of structure, we present a comprehensive review concerning the chemical structure and conformation of RG-I, its functions in plants and properties in solutions.

Biochemical Characterization of Two Rhamnogalacturonan Lyases From Bacteroides ovatus ATCC 8483 With Preference for RG-I Substrates

Rhamnogalacturonan lyase (RGL) cleaves backbone α-1,4 glycosidic bonds between L-rhamnose and D-galacturonic acid residues in type I rhamnogalacturonan (RG-I) by β-elimination to generate RG oligosaccharides with various degrees of polymerization. Here, we cloned, expressed, purified and biochemically characterized two RGLs (Bo3128 and Bo4416) in the PL11 family from Bacteroides ovatus ATCC 8483. Bo3128 and Bo4416 displayed maximal activity at pH 9.5 and pH 6.5, respectively. Whereas the activity of Bo3128 could be increased 1.5 fold in the presence of 5 mM Ca²⁺, Bo4416 required divalent metal ions to show any enzymatic activity. Both of RGLs showed a substrate preference for RG-I compared to other pectin domains. Bo4416 and Bo3128 primarily yielded unsaturated RG oligosaccharides, with Bo3128 also producing them with short side chains, with yields of 32.4 and 62.4%, respectively. Characterization of both RGLs contribute to the preparation of rhamnogalacturonan oligosaccharides, as well as for the analysis of the fine structure of RG-I pectins.

Structure of KOH-extractable polysaccharides of tree greenery of from Siberian fir Abies sibirica Ledeb

Polysaccharide AS_K was extracted with aqueous KOH from the Abies sibirica foliage. Pectin, xylan, AGPs and xyloglucan were isolated from AS_K by anion-exchange chromatography and Smith degradation, combined with enzymatic cleavage. Potential interactions between those polymers were examined. Since xylan, AGPs, RG-I and glucan were co-fractionated following complete removal of galacturonan (HG) with polygalacturonase, it can be inferred that the enzymatic cleavage of HG did not affect co-fractionation of cross-linking glycans, RG-I and AGPs. These were hypothesized to be bound via a covalent cross-link, as the removal of HG regions did not affect this complex. Given that pectin was represented solely by RG-I regions, it can be assumed that some of glucan, xylan and AGPs were associated directly with RG-I. Besides, the enzymatic hydrolysis eliminated most of xylose and rhamnose. This suggests implicitly that some of xylan was linked to RG-I.

Structural characterization of polysaccharide from yellow sweet potato and ameliorates DSS-induced mice colitis by active GPR41/MEK/ERK 1/2 signaling pathway

A polysaccharide isolated from yellow sweet potato (Ipomoea batatas (L.) Lam.) consisted of Rha, Ara, Gal, Glc, GalA, GlcA with the ratio of 1.00, 2.00, 3.63, 1.21, 1.17, 1.14, respectively. The molecular weight (Mw) of RSPP-A was determinted to be 2.51×10⁶ kDa. Methylation, Nuclear Magnetic Resonance (NMR) (1D & 2D) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that RSPP-A possessed six glycosidic bonds including α-L-Araf-(1→, →5)-α-L-Araf-(1→, →6)-β-D-Galp-(1→, β-D-Glcp-(1→, →3)-α-L-Araf-(1→, →3)-α-L-Rhap-(1→. In dextran sulfate sodium (DSS) induced mouse-acute-colitis model, the results indicated that RSPP-A could down- regulate the secretion of IL-6 and IL-1β, and promote the secretion of IL-10 in serum and colon, which also suggested that RSPP-A could enhance the contents of short chain fatty acids(SCFAs) and up-regulate the expression of G protein-coupled receptor (GPR41) in colon. Moreover, the expression of Mitogen-activated protein kinase kinase (MEK), extracellular signal-regulated kinase 1/2 (ERK1/2) were up-regulated in colon after intervention with RSPP-A, result from above suggested that the anti-inflammatory activity might be related to the production of SCFA, activating GPR41/MEK/ERK1/2 signaling pathway.

Comparisons of Isolation Methods, Structural Features, and Bioactivities of the Polysaccharides from Three Common Panax Species: A Review of Recent Progress

Panax spp. (Araliaceae family) are widely used medicinal plants and they mainly include Panax ginseng C.A. Meyer, Panax quinquefolium L. (American ginseng), and Panax notoginseng (notoginseng). Polysaccharides are the main active ingredients in these plants and have demonstrated diverse pharmacological functions, but comparisons of isolation methods, structural features, and bioactivities of these polysaccharides have not yet been reported. This review summarizes recent advances associated with 112 polysaccharides from ginseng, 25 polysaccharides from American ginseng, and 36 polysaccharides from notoginseng and it compares the differences in extraction, purification, structural features, and bioactivities. Most studies focus on ginseng polysaccharides and comparisons are typically made with the polysaccharides from American ginseng and notoginseng. For the extraction, purification, and structural analysis, the processes are similar for the polysaccharides from the three Panax species. Previous studies determined that 55 polysaccharides from ginseng, 18 polysaccharides from American ginseng, and 9 polysaccharides from notoginseng exhibited anti-tumor activity, immunoregulatory effects, anti-oxidant activity, and other pharmacological functions, which are mediated by multiple signaling pathways, including mitogen-activated protein kinase, nuclear factor kappa B, or redox balance pathways. This review can provide new insights into the similarities and differences among the polysaccharides from the three Panax species, which can facilitate and guide further studies to explore the medicinal properties of the Araliaceae family used in traditional Chinese medicine.

In vitro modulatory effects of ginsenoside compound K, 20(S)-protopanaxadiol and 20(S)-protopanaxatriol on uridine 5'-diphospho-glucuronosyltransferase activity and expression

We explored the inhibitory effect of ginsenoside compound K (CK), 20(S)-protopanaxadiol (PPD), and 20(S)-protopanaxatriol (PPT) on six uridine 5'-diphospho-glucuronosyltransferase (UGT) enzyme (UGT1A1, 1A3, 1A4, 1A6, 1A9, and 2B7) activities in human liver microsomes (HLMs) and 10 UGT enzyme (UGT1A1, 1A3, 1A4, 1A6, 1A9, 2B4, 2B7, 2B10, 2B15, and 2B17) activities in recombinant UGT isoforms.PPD was a potent inhibitor of UGT1A3 activity with half-maximal inhibitory concentration values of 5.62 and 3.38 μM in HLMs and recombinant UGT1A3, respectively. UGT1A3 inhibition by CK and PPD was competitive with inhibitory constant (K_i) values of 17.4 and 1.21 μM, respectively, and inhibition by PPT was non-competitive with a K_i value of 8.07 μM in HLMs. PPD exhibited more than 3.4-fold selectivity for UGT1A3 inhibition compared with other UGT isoforms inhibition, while CK and PPT showed more than 2.16- and 2.21-fold selectivity, respectively.PPD did not significantly increase the mRNA expression of UGT1A1, 1A3, 1A4, 1A9, and 2B7 in hepatocytes.Given the low plasma concentrations of PPD in healthy human subjects and the absence of induction potential on UGT isoforms, we conclude that PPD cause no pharmacokinetic interactions with other co-administered drugs metabolised by UGT1A3.

Elucidation of the microstructure of an immuno-stimulatory polysaccharide purified from Korean red ginseng using sequential hydrolysis

The elucidation of the structural characteristics of polysaccharides from natural sources is generally difficult owing to their structural complexity and heterogeneity. In our previous study, an immuno-stimulatory polysaccharide (RGP-AP-I) was isolated from Korean red ginseng (Panax ginseng C.A. Meyer). The present study aims to elucidate the structural characteristics of RGP-AP-I. Sequential enzyme hydrolysis was performed using four specific glycosylases, and chemical cleavage via β-elimination was carried out to determine the fine structure of RGP-AP-I. The degraded fragments were chemically identified using various chromatographic and spectrometric analyses, including HPLC-UVD, GC-MS, and tandem mass spectrometry. The results indicated that RGP-AP-I comprises a rhamnogalacturonan I (RG-I) backbone with repeating disaccharide units [→2)-Rhap-(1 → 4)-GalAp-(1→] and three side chains substituted at the C(O)4 position of the rhamnose residue in the backbone. The three side chains were identified as a highly branched α-(1 → 5)-arabinan, a branched β-(1 → 4)-galactan, and an arabino-β-3,6-galactan. Our results represent the first findings regarding the fine structure of the immuno-stimulatory polysaccharide RG-AP-I isolated from red ginseng.

Characterization of pectin-xylan-glucan-arabinogalactan proteins complex from Siberian fir Abies sibirica Ledeb

Polysaccharide AS_K was isolated from the Abies sibirica foliage by extraction with an aqueous KOH solution. AS_K was shown to contain structurally different polymers such as arabinoglucuronoxylans, xyloglucans, glucomannans, arabinogalactan-proteins (AGPs). The pectic polysaccharides were also found in the alkaline extract of AS_K and were represented by regions of homogalactorunan and rhamnogalactouronan-I whose side sugar chains were made up chiefly of highly branched 1,5-α-l-arabinan. The potential couplings between those polysaccharides were examined. Our studies showed simultaneous elution of pectin, xyloglucans, arabinoglucuronoxylans and AGPs, indicating that pectins can be covalently bound to the other cell-wall polysaccharides. NMR spectroscopy results revealed that the polysaccharides obtained by ion-exchange chromatography almost had no free reducing ends. These findings corroborate the conclusion that pectin, AGPs, glucan and xylan are bound together. The existence of the covalently bound complex of pectin-xylan-xyloglucan-AGP is suggested herein. Pectin and xylan are hypothesized to be covalently linked through RG-I regions.

Pectic polysaccharides from Radix Sophorae Tonkinensis exhibit significant antioxidant effects

Two pectic polysaccharides (WRSP-A2b and WRSP-A3a) have been obtained from Radix Sophorae Tonkinensis and comparatively investigated in terms of their physical properties and antioxidant activities. Monosaccharide composition, FT-IR, NMR and enzymatic analyses indicate that both WRSP-A2b (13.6 kDa) and WRSP-A3a (44.6 kDa) consist of homogalacturonan (HG), rhamnogalacturonan I (RG-I) and rhamnogalacturonan II (RG-II) domains, with mass ratios of 0.9:1.8:1 and 2.3:2.9:1, respectively. The RG-I domains were further purified and characterized. Results show that WRSP-A2b contains a highly branched RG-I domain, primarily substituted with α-(1→5)-linked arabinans, whereas WRSP-A3a contains a small branched RG-I domain mainly composed of β-(1→4)-linked galactan side chains. WRSP-A3a exhibits stronger antioxidant activity in scavenging different radicals than WRSP-A2b, a finding that may be due to its higher content of GalA residues and HG domains. Our results provide useful information for screening natural polysaccharide-based antioxidants from Radix Sophorae Tonkinensis.

Structural characterization and immunomodulatory activity of a heterogalactan from Panax ginseng flowers

A neutral polysaccharide fraction (WGFPN) was isolated from Panax ginseng flowers. Monosaccharide composition and HPSEC-MALLS-RI (high-performance size exclusion chromatography coupled with multi-angle laser light scattering detector and refractive index detector) analyses showed WGFPN was a heterogalactan with a molecular weight of 11.0 kDa. Methylation, 1D/2D NMR (nuclear magnetic resonance) spectra and enzymatic hydrolysis methods were used to characterize the structure of WGFPN. It possessed a less branched (1 → 4)-β-D-galactan and a significantly branched (1 → 6)-β-D-galactan. The side chains of (1 → 6)-β-D-galactan were branched with α-L-1,5-Araf and t-α-L-Araf residues at O-3. Trace amount of 1,4-linked Glcp, terminal Galp, terminal Glcp and terminal Manp residues might attached to the 1,6-linked galactan through O-3 or 1,4-linked galactan through O-6 as side chains. WGFPN could activate RAW264.7 macrophages through increasing macrophage phagocytosis, releasing NO and secreting TNF-α, IL-6, IFN-γ and IL-1β in vitro. Moreover, WGFPN could enhance the immunity of cyclophosphamide (CTX)-induced immunosuppressed mice in vivo. Hence, WGFPN might be a potential natural immunomodulatory agent.

Polysaccharides from natural resources exhibit great potential in the treatment of ulcerative colitis: A review

The incidence of ulcerative colitis (UC) is high. Despite the availability of various therapeutic agents for the treatment of UC, the routine treatment has limitations and serious side effects. Therefore, a new drug that safely and effectively treats UC is urgently needed. Polysaccharides from natural resources have recently become a hot topic of study for their therapeutic effects on UC. These effects are associated with the regulation of inflammatory cytokines, intestinal flora, and immune system and protection of the intestinal mucosa. This review focuses on the recent advances of polysaccharides from natural resources in the treatment of UC. The mechanisms and practicability of polysaccharides, including pectin, guar gum, rhamnogalacturonan, chitosan, fructan, psyllium, glycosaminoglycan, algal polysaccharides, polysaccharides from fungi and traditional Chinese medicine, and polysaccharide derivatives, are discussed in detail. The good efficacy and safety of polysaccharides make them promising drugs for treating UC.

Chemical constituents of Panax ginseng and Panax notoginseng explain why they differ in therapeutic efficacy

Panax ginseng (Meyer) and Panax notoginseng (Burkill), belonging to the family Araliaceae, are used worldwide as medicinal and functional herbs. Numerous publications over the past decades have revealed that both P. notoginseng and P. ginseng contain important bioactive ingredients such as ginsenosides and exert multiple pharmacological effects on nervous system and immune diseases. However, based on traditional Chinese medicine (TCM) theory, their applications clearly differ as ginseng reinforces vital energy and notoginseng promotes blood circulation. In this article, we review the similarities and differences between ginseng and notoginseng in terms of their chemical composition and pharmacological effects. Their chemical comparisons indicate that ginseng contains more polysaccharides and amino acids, while notoginseng has more saponins, volatile oil, and polyacetylenes. Regarding pharmacological effects, ginseng exhibits better protective effects on cardiovascular disease, nerve disease, cancer, and diabetes mellitus, whereas notoginseng displays a superior protective effect on cerebrovascular disease. The evidence presented in this review facilitates further research and clinical applications of these two herbs, and exploration of the relationship between the chemical components and disease efficacy may be the critical next step.

The Effect of Different Extraction Conditions on the Physical Properties, Conformation and Branching of Pectins Extracted from Cucumis melo Inodorus

The extraction of pectin involves the physico-chemical hydrolysis and solubilisation of pectic polymers from plant tissues under the influence of several processing parameters. In this study, an experimental design approach was used to examine the effects of extraction pH, time and temperature on the pectins extracted from Cucumis melo Inodorus. Knowledge of physical properties (intrinsic viscosity and molar mass), dilute solution conformation (persistence length and mass per unit length), together with chemical composition, was then used to propose a new method, which can estimate the length and number of branches on the pectin RG-I region. The results show that physical properties, conformation and the length and number of branches are sensitive to extraction conditions. The fitting of regression equations relating length and number of branches on the pectin RG-I region to extraction conditions can, therefore, lead to tailor-made pectins with specific properties for specific applications.

An Atomic Force Microscopy Study on the Effect of β-Galactosidase, α-L-Rhamnosidase and α-L-Arabinofuranosidase on the Structure of Pectin Extracted from Apple Fruit Using Sodium Carbonate

The enzyme driven changes in plant cell wall structure during fruit ripening result in debranching, depolymerization and solubilization of pectin polysaccharides, which has an effect in terms of the postharvest quality losses in fruit. Atomic force microscopy (AFM) has revealed that diluted alkali soluble pectins (DASP) from fruit and vegetables have an interesting tendency to self-assemble into regular structures. However, the mechanism is not yet fully understood. The current study is aimed at investigating the role of neutral sugars, namely galactose, rhamnose and arabinose in the formation of the branched structure of DASP. β-galactosidase, α-L-rhamnosidase and α-L-arabinofuranosidase enzymes were used for the treatment of DASP extracted from Golden Delicious apple flesh (Malus domestica cv. Golden Delicious). The effects of the selective degradation of pectic polysaccharides after 15, 30, 60, 90 and 120 min of incubation were observed using AFM. The α-L-rhamnosidase enzyme activity on pectin extracted with Na2CO3 did not cause any visible or measurable degradation of the molecular structure. The moderate effects of β-galactosidase enzymatic treatment suggested the possible role of galactose in the branching of DASP molecules deposited on mica. Data obtained for α-L-arabinofuranosidase indicated the crucial role of arabinose in the formation and preservation of the highly branched structure of the DASP fraction.

Rethinking the impact of RG-I mainly from fruits and vegetables on dietary health

Rhamnogalacturonan I (RG-I) pectin is composed of backbone of repeating disaccharide units →2)-α-L-Rhap-(1→4)-α-D-GalpA-(1→ and neutral sugar side-chains mainly consisting of arabinose and galactose having variable types of linkages. However, since traditional pectin extraction methods damages the RG-I structure, the characteristics and health effects of RG-I remains unclear. Recently, many studies have focused on RG-I, which is often more active than the homogalacturonan (HG) portion of pectic polysaccharides. In food products, RG-I is common to fruits and vegetables and possesses many health benefits. This timely and comprehensive review describes the many different facets of RG-I, including its dietary sources, history, metabolism and potential functionalities, all of which have been compiled to establish a platform for taking full advantage of the functional value of RG-I pectin.

A Novel PL9 Pectate Lyase from Paenibacillus polymyxa KF-1: Cloning, Expression, and Its Application in Pectin Degradation

Pectate lyases play an important role in pectin degradation, and therefore are highly useful in the food and textile industries. Here, we report on the cloning of an alkaline pectate lyase gene (pppel9a) from Paenibacillus polymyxa KF-1. The full-length gene (1350 bp) encodes for a 449-residue protein that belongs to the polysaccharide lyase family 9 (PL9). Recombinant PpPel9a produced in Escherichia coli was purified to electrophoretic homogeneity in a single step using Ni2+-NTA affinity chromatography. The enzyme activity of PpPel9a (apparent molecular weight of 45.3 kDa) was found to be optimal at pH 10.0 and 40 °C, with substrate preference for homogalacturonan type (HG) pectins vis-à-vis rhamnogalacturonan-I (RG-I) type pectins. Using HG-type pectins as substrate, PpPel9a showed greater activity with de-esterified HGs. In addition, PpPel9a was active against water-soluble pectins isolated from different plants. Using this lyase, we degraded citrus pectin, purified fractions using Diethylaminoethyl (DEAE)-sepharose column chromatography, and characterized the main fraction MCP-0.3. High-performance gel permeation chromatography (HPGPC) analysis showed that the molecular mass of citrus pectin (~230.2 kDa) was reduced to ~24 kDa upon degradation. Ultra-performance liquid chromatography - tandem mass spectrometer (UPLC-MS) and monosaccharide composition analyses demonstrated that PpPel9a worked as an endo-pectate lyase, which acted primarily on the HG domain of citrus pectin. In vitro testing showed that the degradation product MCP-0.3 significantly promotes the growth of Lactobacillus plantarum and L. rhamnosus. In this regard, the enzyme has potential in the preparation of pharmacologically active pectin products.