Structure, physicochemical characterization, and antioxidant activity of the highly arabinose-branched exopolysaccharide EPS-M2 from Streptococcus thermophilus CS6.

Streptococcus thermophilus CS6 could produce the high exopolysaccharide (EPS) level in optimized skimmed milk medium. However, physicochemical properties and structure of these polymers have not been fully characterized. In this study, two purified fractions (EPS-M1 and EPS-M2) exhibited good rheology, thermostability and antioxidant activity. Further monosaccharide composition, molecular weight and NMR analysis indicated EPS-M2 was composed of galactose, arabinose and glucose (5:2.5:1) with an average molecular weight of 2.22 × 104 Da and its suggested repeating unit was →6)-[α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1 â†’ 4)-ß-D-Galp-(1 â†’ 6)-[α-L-Araf-(1 â†’ 5)-{α-L-Araf-(1 â†’ 3)}-α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1 â†’ 4)-ß-D-Galp-(1 â†’ 6)-[ß-D-Galp-(1 â†’ 5)-α-L-Araf-(1 â†’ 5)-α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1 â†’ 6)-[ß-D-Galp-(1 â†’ 5)-α-L-Araf-(1 â†’ 5)-{α-L-Araf-(1 â†’ 3)}-α-L-Araf-(1 â†’ 3)]-ß-D-Galp-(1→. High EPS production relied on the expression of eps gene cluster and key enzymes of nucleotide sugar metabolism. Overall, EPS-M2 from a potential functional starter S. thermophilus CS6 provided opportunities for natural thickener, stabilizer, and antioxidant agent exploration in the food industry.

Synthesis and antitumor activity evaluation of oleanolic acid saponins bearing an acetylated l-arabinose moiety.

A series of oleanolic acid derivatives bearing acetyl-substituted l-arabinose moiety has been synthesized and screened in vitro for cytotoxicity against ten cancer cell lines and four normal cell lines. The antiproliferative evaluation indicated that synthetic derivatives showed excellent selectivity, as they were toxic against only A431 cell line. Among them, the compound 6 possesses the best inhibitory activity. A series of pharmacology experiments showed that compound 6 significantly induced A431 cells apoptosis and cell cycle arrest, which could serve as a promising lead candidate for further study.

Structural elucidation and immuno-stimulatory activity of a novel polysaccharide containing glucuronic acid from the fungus Echinodontium tinctorium.

An immuno-stimulatory polysaccharide (EtISPFa) was purified from water extract of the fungus Echinodontium tinctorium. EtISPFa has an estimated weight average molecular weight (Mw) of 1354 kDa and is composed of glucose (66.2 %), glucuronic acid (10.1 %), mannose (6.7 %), galactose (6.4 %), xylose (5.6 %), rhamnose (3.1 %), fucose (1.8 %), and arabinose (0.2 %). It has multiple glycosidic linkages, with 3-Glcp (19.8 %), 4-GlcpA (10.8 %), 6-Glcp (10.7 %), and 3,6-Glcp (8.7 %) being the most prominent. NMR analysis showed that EtISPFa has a backbone containing mostly of 3-substituted ß-glucopyranose with 4-substituted glucopyranosyluronic acid. Short side chains consisting of an average of two ß-glycopyranose residues, connected through 1→6 linkages, are attached to the 6-position of about every 4th or 5th backbone glucose residue. EtISPFa is a novel glucuronic acid-containing ß-glucan capable of significantly inducing the production of cytokines IL-17, IL-16, MIP-2, G-CSF,GM-CSF, LIF, MIP-1α, MIP-1ß, and RANTES in vitro. EtISPFa should be further explored for its immuno-stimulatory activity in vivo.

Ultrafiltration isolation, structures and anti-tumor potentials of two arabinose- and galactose-rich pectins from leaves of Aralia elata.

Two novel arabinose- and galactose-rich pectic polysaccharides, AELP-B5 (Mw, 4.25 × 104 g/mol) and B6 (Mw, 1.56 × 104 g/mol), were rapidly obtained from the leaves of Aralia elata (Miq.) Seem. with anion resin and sequenced ultrafiltration membrane columns. The structural backbone and branched chains of AELP-B5 and B6 were preliminarily elucidated by mild acid hydrolysis with HILIC-ESI--MS/MS. The planar structures and spatial configurations were further identified using UPLC-QDa and GC-MS for compositions, Smith degradation and methylation analysis, FT-IR, NMR (1H/13C, DEPT, HSQC, HMBC, COSY, NOESY and TOCSY) and SEC-MALLS-RID. (1) AELP-B5 possessed →4GalA1→ as smooth regions (HG) and a repeating disaccharide moiety of →4GalA1→2Rha1→ as hairy regions (RG-I) with a 1:5 molar ratio, whereas AELP-B6 had a distinguishing 1:1 molar ratio between the HG and RG-I; (2) complex side chains were constituted of T-α-Araf, 1,3-α-Araf, 1,5-α-Araf, T-ß-Galp, 1,3-ß-Galp, 1,4-ß-Galp, 1,6-ß-Galp, 1,3,4-ß-Galp and 1,3,4,6-ß-Galp connected at C-4 of the rhamnosyl units in RG-I of AELP-B5 and B6; and (3) both possessed highly branched and compact coil conformations. The CCK-8 assay illustrated that AELP-B6 possessed higher cytotoxicity against HepG2 and HT-29 than that of AELP-B5. Surface plasmon resonance showed the binding affinity of AELP-B6 to galectin-3 (6.488 × 10-5 M) was about 10 times stronger than that of AELP-B5 (4.588 × 10-4 M). The above findings provide a molecular structure and bioactivity basis for future potential applications of AELP in the food and medical industries.

Structural and immunological studies on the polysaccharide from spores of a medicinal entomogenous fungus Paecilomyces cicadae.

A neutral branched heteropolysaccharide (Pc0-1) was purified from the spores of Paecilomyces cicadae, which parasitized in the bamboo cicada (Platylomia pieli Kato). The structure of Pc0-1 was analyzed by HPLC, IR, methylation and NMR spectroscopy. The results reveal that Pc0-1, with an average molecular weight of 18 × 103 kDa, consists of glucose, galactose, mannose and arabinose in the molar ratio of 8:5:4:1. Some of the glucose residues have methyl modification at O-6 position. The Pc0-1 polysaccharide has a core structure containing 1,2-linked α-d-Manp residues as the backbone and branches at the O-3 and O-6 of the α-d-Manp residues. The inner part of the side-chains is comprised of 1,4-linked α-d-Glcp and 1,4-linked 6-O-Me-α-d-Glcp residues. 1,2-linked ß-Galf and minor 1,4-linked Arap and 1,3 or 4-linked Arap residues were occasionally linked at the outside of the side-chains. The side-chains have a single terminal residue of α-d-Glcp, α-Manp, ß-Galf or minor Arap (minor). Studies on the bioactivity of Pc0-1 on the macrophages show it exhibit moderate immunostimulating activity through increasing the production of nitric oxide (NO) and enhancing the secretion of major inflammatory cytokines by macrophages, such as TNF-α, IL-1ß, IL-6, in RAW 264.7 cells. We examined the effect of Pc0-1 on induced NO and cytokine production in macrophages using anti-PRR antibodies to investigate the membrane receptor for the polysaccharide. The results show that Pc0-1 mainly activates macrophages through their mannose receptor (MR). TLR4 and TLR2 also participated in the recognition of Pc0-1.

Isolation, purification, structure and antioxidant activity of polysaccharide from pinecones of Pinus koraiensis.

The polysaccharides (PKP-E) extracted from the pinecones of Pinus koraiensis were studied, which was fractionated using DEAE-52 cellulose and Sephadex G-100. Four novel polysaccharide fractions were obtained, which were PKP-E-1-1, -1-2, -2-1, and -2-2, respectively. The structural features were characterized using HPGPC, monosaccharide composition analysis, Congo red test, periodate oxidation, Smith degradation, FTIR and NMR spectroscopy. The results showed the 4 purified fractions were non-triple helical structured heteropolysaccharides and composed of l-rhamnose, l-arabinose, d-mannose, d-glucose, and d-galactose. The fractions were mainly linked by 1→6 or 1→ glycosidic bonds and the backbone of 4 fractions was probably composed of→2, 6)-ß-d-Man-(1→ and α-d-GalpA-(1→), which resembles pectin. Moreover, the antioxidant activities of the polysaccharides were measured by scavenging radical capacity tests. The PKP-E-2-1 was the most stable and active fraction, and the respective IC50 for the hydroxyl and ABTS·+ radicals were 3.0 and 23.6 mg/mL.

A structure-function study of ZraP and ZraS provides new insights into the two-component system Zra.

BACKGROUND: Zra belongs to the envelope stress response (ESR) two-component systems (TCS). It is atypical because of its third periplasmic repressor partner (ZraP), in addition to its histidine kinase sensor protein (ZraS) and its response regulator (ZraR) components. Furthermore, although it is activated by Zn2+, it is not involved in zinc homeostasis or protection against zinc toxicity. Here, we mainly focus on ZraS but also provide information on ZraP. METHODS: The purified periplasmic domain of ZraS and ZraP were characterized using biophysical and biochemical technics: multi-angle laser light scattering (MALLS), circular dichroism (CD), differential scanning fluorescence (DSF), inductively coupled plasma atomic emission spectroscopy (ICP-AES), cross-linking and small-angle X-ray scattering (SAXS). In-vivo experiments were carried out to determine the redox state of the cysteine residue in ZraP and the consequences for the cell of an over-activation of the Zra system. RESULTS: We show that ZraS binds one Zn2+ molecule with high affinity resulting in conformational changes of the periplasmic domain, consistent with a triggering function of the metal ion. We also demonstrate that, in the periplasm, the only cysteine residue of ZraP is at least partially reduced. Using SAXS, we conclude that the previously determined X-ray structure is different from the structure in solution. CONCLUSION: Our results allow us to propose a general mechanism for the Zra system activation and to compare it to the homologous Cpx system. GENERAL SIGNIFICANCE: We bring new input on the so far poorly described Zra system and notably on ZraS.

Structure of a GH51 α-L-arabinofuranosidase from Meripilus giganteus: conserved substrate recognition from bacteria to fungi.

α-L-Arabinofuranosidases from glycoside hydrolase family 51 use a stereochemically retaining hydrolytic mechanism to liberate nonreducing terminal α-L-arabinofuranose residues from plant polysaccharides such as arabinoxylan and arabinan. To date, more than ten fungal GH51 α-L-arabinofuranosidases have been functionally characterized, yet no structure of a fungal GH51 enzyme has been solved. In contrast, seven bacterial GH51 enzyme structures, with low sequence similarity to the fungal GH51 enzymes, have been determined. Here, the crystallization and structural characterization of MgGH51, an industrially relevant GH51 α-L-arabinofuranosidase cloned from Meripilus giganteus, are reported. Three crystal forms were grown in different crystallization conditions. The unliganded structure was solved using sulfur SAD data collected from a single crystal using the I23 in vacuo diffraction beamline at Diamond Light Source. Crystal soaks with arabinose, 1,4-dideoxy-1,4-imino-L-arabinitol and two cyclophellitol-derived arabinose mimics reveal a conserved catalytic site and conformational itinerary between fungal and bacterial GH51 α-L-arabinofuranosidases.

Study on structure characterization of pectin from the steamed ginseng and the inhibition activity of lipid accumulation in oleic acid-induced HepG2 cells.

Two acid polysaccharides were obtained from steamed ginseng (GPS-1 and GPS-2) through water extraction, ion-exchange chromatography and gel chromatography. The structural features and ability of the polysaccharides to inhibit lipid accumulation in oleic acid-induced HepG2 cells were studied. GPS-1 consisted of type I arabinogalactans (AG-I), arabinogalactans-II (AG-II) and rhamnogalacturonan I (RG-I) domains. GPS-2 was a pectin-like polysaccharide consisting mainly of the homogalacturonan (HG) domain and a small amount of AG domain. Both GPS-1 and GPS-2 had branches attaching on O-3 of (1 → 6)-GalA or O-4 of (1 → 2)-Rha and terminated by either Ara or Gal. An in vitro experiment revealed that GPS-1 treatment at 50-400 µg/ml could dose-dependently decrease intracellular lipid accumulation and cholesterol (TC) and triglycerides (TG) levels. GPS-1 exerted a more serious hypolipidemic effect than GPS-2 did. Moreover, GPS-1 considerably increased the phosphorylation of AMP-activated protein kinase (AMPK) and affected the expression of AMPK downstream targets, including the inhibition of the protein expression of sterol regulatory element-binding protein 1c (SREBP-1c) and activation of Acetyl-CoA carboxylase (ACC). Results suggest that GPS-1 could inhibit lipid accumulation via the AMPK the signalling pathway.

Purification, characterization and utilization of polysaccharide of Araucaria heterophylla gum for the synthesis of curcumin loaded nanocarrier.

In this study, gum of Araucaria heterophylla was collected. The collected gum was subjected for extraction of polysaccharide using solvent extraction system. Thus, extracted polysaccharide was further purified using solvent method and was characterized using UV-Vis spectroscopy, Phenol sulfuric acid assay, FTIR, TGA, TLC and GC-MS. The gum derived polysaccharide was found to have the following sugars Rhamnose, Allose, Glucosinolate, Threose, Idosan, Galactose and Arabinose. The extracted polysaccharide was tested for various in-vitro bioactive studies such as antibacterial activity, antioxidant activity and anticancer activity. The polysaccharide was found to have antioxidant and anticancer activity. Further, the polysaccharide was subjected for carboxymethylation to favor the nanocarrier synthesis, where it was chelated using Sodium Tri Meta Phosphate (STMP) to form nanocarriers. The nanocarriers so formed were loaded with curcumin and were characterized using FTIR, SEM, EDX and AFM. Both the loaded and unloaded nanocarriers were studied for its in-vitro cytotoxic effect against the MCF7 human breast cancer cell lines. The nanocarriers were found to deliver the drug efficiently against the cancer cell line used in this study.

Timely Addition of Glutathione for Its Interaction with Deoxypentosone To Inhibit the Aqueous Maillard Reaction and Browning of Glycylglycine-Arabinose System.

The inhibitory effects of glutathione (GSH) and oxiglutathione (GSSG) on Maillard browning were compared, and it was clarified that free sulfhydryl was the key substance for the inhibition. The Amadori rearrangement product (ARP) derived from glycylglycine (Gly-Gly) and arabinose (Ara) was prepared by aqueous Maillard reaction, and LC-MS/MS was used to investigate the reaction products of GSH and purified ARP. Reaction between GSH and deoxypentosone (DP) was found to alter the pathway of aqueous Maillard reaction, which reduced the production of glyoxal, methylglyoxal, and furfural and thereby inhibited the formation of melanoidins. To determine the optimal conditions for browning inhibition, a stepwise increase of temperature was used to prepare Maillard reaction products (MRPs). The results showed that the optimum browning inhibitory effect was obtained by adding GSH after Gly-Gly and Ara heating at 80 °C for 60 min.

Characterizing the selectivity of ER α-glucosidase inhibitors.

The endoplasmic reticulum (ER) contains both α-glucosidases and α-mannosidases which process the N-linked oligosaccharides of newly synthesized glycoproteins and thereby facilitate polypeptide folding and glycoprotein quality control. By acting as structural mimetics, iminosugars can selectively inhibit these ER localized α-glycosidases, preventing N-glycan trimming and providing a molecular basis for their therapeutic applications. In this study, we investigate the effects of a panel of nine iminosugars on the actions of ER luminal α-glucosidase I and α-glucosidase II. Using ER microsomes to recapitulate authentic protein N-glycosylation and oligosaccharide processing, we identify five iminosugars that selectively inhibit N-glycan trimming. Comparison of their inhibitory activities in ER microsomes against their effects on purified ER α-glucosidase II, suggests that 3,7a-diepi-alexine acts as a selective inhibitor of ER α-glucosidase I. The other active iminosugars all inhibit α-glucosidase II and, having identified 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) as the most effective of these compounds, we use in silico modeling to understand the molecular basis for this enhanced activity. Taken together, our work identifies the C-3 substituted pyrrolizidines casuarine and 3,7a-diepi-alexine as promising "second-generation" iminosugar inhibitors.

Comparison on characterization and antioxidant activity of polysaccharides from Ganoderma lucidum by ultrasound and conventional extraction.

The polysaccharides of Ganoderma lucidum (GLP) extracted by the methods of ultrasound assisted extraction (UAE) and hot water extraction (HWE) were characterized and the antioxidant activities of GLPUAE and GLPHWE were compared. High performance gel permeation chromatography (HPGPC) showed that the average molecular weight of GLPUAE and GLPHWE were 465.65 kDa and 703.45 kDa, respectively. GLPUAE was composed of mannose, rhamnose, glucose, galactose and arabinose in the molar ratio of 2.58:1.25:11.17:2.5:1, while GLPHWE was composed of the same monosaccharide in the ratio of 3.11:1.11:19.44:2.33:1. GLPHWE showed a relatively higher antioxidant activity than GLPUAE by testing the reducing power, the scavenging ability on 1.1­diphenyl­2­picryl­hydrazyl (DPPH), hydroxyl radical and cellular protective effect on yeast cells from ultraviolet radiation (UV) damage. GLPUAE and GLPHWE were purified by chromatographic column of DEAE-52 cellulose. GLPUAE, GLPHWE and the purified components could be novel antioxidants for functional food.

Chemical Characterization and Hypoglycaemic Activities In Vitro of Two Polysaccharides from Inonotus obliquus by Submerged Culture.

Polysaccharides from the fungus Inonotus obliquus have been found to be biologically active. In this study, we carried out a preliminary characterisation and assessment of the hypoglycaemic activities of the polysaccharides (IOEP) from Inonotus obliquus obtained by liquid fermentation. Two polysaccharides, IOEP1 and IOEP2, were isolated from IOEP. IOEP1, with a molecular weight of 20 KDa, was mainly composed of galatose and mannose, while IOEP2, with a molecular weight of 200 KDa, was mainly composed of arabinose. Fourier-transform infrared analysis showed that both IOEP1 and IOEP2 were pyran-type polysaccharides. ¹H-NMR spectra showed that the glycosidic bonds of IOEP1 and IOEP2 were both α-type and ß-type. In addition, IOEP1 and IOEP2 strongly increased the glucose consumption of HepG2 cells and insulin-resistant HepG2 cells in vitro. These findings provide a theoretical basis that IOEP1 and IOEP2 might be suitable as anti-diabetes agents in functional foods and natural drugs.

Purification, characterization and immunomodulatory activity of polysaccharides from stem lettuce.

Stem lettuce has a long history of cultivation in China and possesses high nutritional and medicinal value. In our previous studies, extraction optimization, characterization, and bioactivities of stem lettuce polysaccharides (SLP) were investigated. In this study, SLP were further separated into two purified polysaccharides, SLP-1 and SLP-2, by anion exchange chromatography followed by size exclusion chromatography. SLP-1, with a molecular weight of 90 KDa, was mainly composed of galacturonic acid, galactose and arabinose in a molar ratio of 17.6:41.7:33.9. SLP-2, with a molecular weight of 44 KDa, was mainly composed of mannose, galacturonic acid, galactose and arabinose in a molar ratio of 11.5:69.5:9.3:8.2. In addition, both purified polysaccharides contain sulphate radicals, have triple helical structures and can promote macrophage proliferation without cytotoxicity. SLP-2 was better able to stimulate phagocytic and nitric oxide production than SLP-1. The results suggest that polysaccharides from stem lettuce could be explored as immunomodulatory agents in the field of pharmaceuticals and functional foods.

Ab-initio and experimental study of pentose sugar dehydration mechanism in the gas phase.

In this work pentose sugar (D-xylose, D-ribose and D-arabinose) gas phase dehydration reaction was investigated by means of mass spectrometric techniques and theoretical calculations. The ionic species derived from the dehydration reaction of protonated D-ribose and D-arabinose were structurally characterized by their fragmentation patterns and the relative dehydration energies measured by energy resolved CAD mass spectra. The results were compared with those recently obtained for D-xylose in the same mass spectrometric experimental conditions. Dehydration of C1-OH protonated sugars was theoretically investigated at the CCSD(T)/cc-pVTZ//M11/6-311++G(2d,2p) level of theory. Protonated pentoses are not stable and promptly lose a water molecule giving rise to the dehydrated ions at m/z 133. D-xylose, D-ribose and D-arabinose dehydration follows a common reaction pathway with ionic intermediates and transition states characterized by similar structures. Slightly different dehydration energies were experimentally measured and the relative trend was theoretically confirmed. The overall dehydration activation energy follows the order arabinose < ribose < xylose. Gas-phase pentose sugar dehydration leads to the formation of protonated 2-furaldehyde as final product. Based on the experimental and theoretical evidence a new mechanistic hypothesis starting from C1-OH protonation was proposed.

Optimization of the microwave-assisted enzymatic extraction of Rosa roxburghii Tratt. polysaccharides using response surface methodology and its antioxidant and α-d-glucosidase inhibitory activity.

An extraction assay applying microwave-assisted enzymatic treatment for polysaccharides in Rosa roxburghii was developed using response surface methodology. The process parameters were optimized using Plackett-Burman (PB) design and central composite design to enhance the Rosa roxburghii polysaccharide extraction yield. Specific conditions (microwave power, 575W; microwave time, 18min; liquid-to-material ratio, 13.5:1mL/g; and enzyme dose, 6.5g/mL) generated an experimental yield of 36.21±0.62%, which closely agreed with the predicted value of 35.75%. Purification with a DEAE-52 cellulose column generated two fractions, PR-1 (from 6.2×103 to 7.4KDa) and PR-2 (from 559.8 to 106.6KDa). Subsequently, the antioxidant activity and α-d-glucosidase inhibitory activity of the two polysaccharide fractions were assessed; PR-1 exhibited stronger antioxidant activity and α-d-glucosidase inhibitory activity than PR-2. Finally, the monosaccharide composition of PR-1 was determined by HPLC using a 1-phenyl-3-methyl-5-pyrazolone precolumn derivatization method. The result showed that PR-1 contained mannose, ribose, rhamnose, glucosamine hydrochloride, glucuronic acid, galacturonic acid, glucose, galactose, arabinose and fucose with molar percentages of 2.1%, 0.54%, 2.1%, 0.26%, 1.5%, 22.7%, 24.0%, 26.4%, 19.6% and 0.89%, respectively.

Structural characterization and antioxidant activity of polysaccharide from ginger.

Two components ginger polysaccharide 1 (GP1) and ginger polysaccharide 2 (GP2) were extracted. The results showed that the molecular weights of GP1 and GP2 were 6128 Da and 12,619 Da, respectively. The composition and proportion of GP1 and GP2 were mannose, glucose and galactose in a molar ratio of 4.96: 92.24: 2.80 and arabinose, mannose, glucose and galactose in a molar ratio of 4.78: 16.70: 61.77: 16.75, respectively, illustrating that GP1 and GP2 were not a kind of homopolysaccharide. GP1 has a three-helix structure, and the structure is closely linked. GP2 contains sulfuric acid groups, and has a high oxidation resistance, its structure is more evacuated and messy.

Structure of a pectic polysaccharide from Pseudostellaria heterophylla and stimulating insulin secretion of INS-1 cell and distributing in rats by oral.

A water-soluble, pectic polysaccharide named as 0.5MSC-F isolated from Pseudostellaria Heterophylla with a molecular weight of 4.8×104Da that was composed of rhamnose, galactose, arabinose, and galacturonic acid which the major monosaccharide contents range up to 63.20%. Where the main chain was consists of 1,4-linked galacturonic acid and a small amount of 1,2-linked rhamnose was embedded into backbone to connect alternative galacturonic acid in the form of Rhamnogalacturonan I (RG-I) structure. 1, 5-linked arabinose through C-4 of 1, 2-linked rhamnose, another 1, 3 or 1,6-linked galactose through C-4 of 1, 2-linked rhamnose, was interconnected to branch chain. 0.5MSC-F could obviously stimulated insulin secretion of islet cells cultured in high glucose are of potential practical value in the hypoglycemic action. Radioisotopes 99mTc-labeled-0.5MSC-F was analyzed by SPECT/CT image after oral in rats. At 2h post ingestion, above 40% of the radioactivity was observed in the intestine, but no found in the heart, liver, and kidney. Conjecturing absorption of 99mTc-labeled 0.5MSC-F might via intestinal mucosa absorption into the systemic circulation.

Characterization of a pectin from Lonicera japonica Thunb. and its inhibition effect on Aß42 aggregation and promotion of neuritogenesis.

Pectin is a class of complex polysaccharides and recognized for its potential bioactivities. In this study, we showed that a pectic polysaccharide, LFA03-a, was extracted from Lonicera japonica Thunb. flowers and purified with DEAE-cellulose and Sephacryl S-100HR. LFA03-a was composed of rhamnose, arabinose, galactose and galacturonic acid in the molar ratio of 18.1:25.3:36.8:19.5. Its structure was determined to possess a rhamnogalacturonan I (RG-I) backbone consisting of α-l-1,2-Rhap and α-d-1,4-GalAp disaccharide repeating unit, substituted at O-4 of l-rhamnose. The side chain was involved with ß-d-1,4-Galp, ß-d-1,3-Galp, ß-d-1,3,6-Galp and branched α-l-1,5-Araf. Fluorescence spectroscopic analysis with thioflavine T (ThT) and atomic force microscopy (AFM) results showed that LFA03-a inhibited Aß42 aggregation in a dose dependent manner and impeded Aß42 oligomerization and fibril formation. In addition, LFA03-a mildly induced the differentiation of PC12 cells and promoted neuritogenesis.The results suggested that pectin LFA03-a might be a potential targeted therapeutic drug for Alzheimer's disease.