Seperation, characterization and inhibition on α-glucosidase, α-amylase and glycation of a polysaccharide from blackcurrant fruits

Fine structure and hypoglycemic effect of a galactoglucan from the bulbs of Lanzhou lily

The present research aimed to further identify the fine structure, morphology, and thermal behaviors of a galactoglucan BHP-2 derived from Lanzhou lily bulbs through partial acid hydrolysis, methylation, 2D NMR (1H1H COSY, HSQC, and HMBC), scanning electron microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). Additionally, the study assessed the potential in vitro hypoglycemic effect of BHP-2 by examining its inhibitory effect on α-glucosidase and α-amylase. The results indicated that the main backbone composition of BHP-2 consisted of →4)-α-D-Glcp-(1→, →3)-β-D-Glcp-(1 → and →6)-β-D-Galp-(1→, while the side chain composition predominantly featured →4)-α-D-Glcp-(1→, →3,5)-α-L-Araf-(1 → and →3)-β-D-Galp-(1→, attached to the C-2 and/or C-3 positions of →4)-α-D-Glcp-(1→. Terminal residues consisted of α-D-Glcp-(1 → and β-L-Araf-(1→. BHP-2 exhibited excellent thermal stability, with a microscopic surface characterized by tightly packed sheets and numerous spiral depressions, which might contribute to its remarkable in vitro hypoglycemic effect. BHP-2 showed competitive inhibition of α-amylase and mixed non-competitive inhibition of α-glucosidase, with respective IC50 values of 0.31 and 0.18 mg/mL, closely resembling to those of acarbose (0.27 and 0.12 mg/mL). These findings suggested that BHP-2 had potential as an additive for glycemic intervention.

Preparation of Ribes nigrum L. polysaccharides-stabilized selenium nanoparticles for enhancement of the anti-glycation and α-glucosidase inhibitory activities

Seven kinds of selenium nanoparticles (RP-SeNPs) were prepared by using the polysaccharides extracted from Ribes nigrum L. (RP) as the stabilizer and dispersant. Among them, RP-SeNPs-1 (94.2 nm), RP-SeNPs-2 (101.2 nm) and RP-SeNPs-3 (107.6 nm) with relatively smaller mean particle size exhibited stronger α-glucosidase inhibitory activity than other RP-SeNPs (115.3-164.2 nm) and SeNPs (288.9 nm). Ultraviolet-visible spectrophotometry, Fourier transform-infrared, X-ray diffraction, energy dispersive X-ray and X-ray photoelectron spectroscopy analyses confirmed that SeNPs were ligated with RP to form nanocomposites and displayed amorphous form. Electron microscopy images revealed that RP-SeNPs-1 - RP-SeNPs-3 were regular shape spherical nanocomposites with much better dispersion than SeNPs. Compared with SeNPs, RP-SeNPs displayed relatively high thermal, storage, pH and salt ion stability. Moreover, RP-SeNPs-1-RP-SeNPs-3 showed significantly better anti-glycation and α-glucosidase inhibitory activity than SeNPs, especially RP-SeNPs-1 with the smallest particle size. Inhibitory kinetics analysis indicated that SeNPs and RP-SeNPs inhibited α-glucosidase with competitive type and reversible mechanism. In addition, the conformation of the α-glucosidase was changed after binding with the SeNPs and RP-SeNPs-1. Fluorescence quenching and isothermal titration calorimetry assays revealed that these two nanoparticles could interact with α-glucosidase to form non-fluorescent complexes through hydrogen bonding, and the formation was spontaneously driven by enthalpy.

Evaluation of In Vitro Antioxidant, Anti-Obesity, and Anti-Diabetic Activities of Opuntia ficus Cladodes Gel and Its Application as a Preservative Coating for Shrimp during Refrigerated Storage

Opuntia ficus cladodes (OFC) are considered one of the wastes that result from opuntia cultivation, and their disposal by traditional methods results in many environmental problems. Therefore, this study was conducted with two aims. The first was the production of OFC gel, and the evaluation of its in vitro antioxidant (by two methods, DPPH and ABTS), anti-obesity, and anti-diabetic activities. The second was an investigation of the effects of different concentrations of this gel (0, 50, and 100%) as an edible coating on the quality of shrimp during 8 days of refrigerated storage. The results showed that this gel was characterised by a high content of ash (10.42%), total carbohydrates (75.17%), and total phenols (19.79 mg GAE/g). OFC gel contained six types of sugars: arabinose, xylose, galactose, rhamnose, glucose, and uronic acid, and the most abundant was xylose (36.72%). It is also clear from the results that the OFC gel had high antioxidant properties, which were higher against DPPH than ABTS at the same concentration. OFC gel showed a high inhibition activity against lipase, α-glycosidase, and α-amylase enzymes, and their IC50 values were 1.43 mg/mL, 0.78 mg/mL, and 0.57 mg/mL, respectively. The results also stated that shrimp coated with OFC gel had lower pH, drip loss, TVB-N, and TBA values through the days of refrigerated storage. Moreover, the shrimp coated with 100% OFC gel were better than those coated with 50% OFC gel. In conclusion, OFC gel showed high potency as active antioxidant, for its enzyme anti-activities, and as an edible coating for shrimp.

Characterization of manganized soluble dietary fiber complexes from tigernut meal and study of the suppressive activity of digestive enzymes in vitro

In this study, manganized soluble dietary fiber (SDF-Mn(II)) was prepared from tigernut meal using a microwave solid-phase synthesis method with SDF. Microscopic morphological and structural analyses of SDF-Mn(II) were carried out using scanning electron microscopy, Fourier infrared spectroscopy, UV full-band scanning, X-ray diffraction, a thermal analyzer, gel permeation chromatography, and nuclear magnetic resonance, and its in vitro hypoglycemic activity was initially investigated. The results of these analyses revealed that the reaction of Mn(II) with SDF mainly involved hydroxyl and carbonyl groups, with the Nuclear magnetic resonance (NMR) analysis showing that specific covalent binding was produced and substitution was mainly carried out at the C₆ position. Moreover, compared with SDF, the SDF-Mn(II) complex exhibited a porous structure, red-shifted, and color-enhancing effects on the UV characteristic peaks, significantly increased crystallinity and decreased molecular weight, and improved thermal stability; in addition, SDF-Mn(II) afforded significantly enhanced inhibition of α-amylase and α-glucosidase and possesses good in vitro digestive enzyme inhibition activity.

Ultrasound-assisted enzymatic extraction of Scutellaria baicalensis root polysaccharide and its hypoglycemic and immunomodulatory activities

Scutellaria baicalensis is a medicinal plant possessing abundant bioactive polysaccharides. This study aimed to optimize the ultrasound-assisted enzymatic extraction of S. baicalensis root polysaccharide (SRP) and investigate its hypoglycemic and immunomodulatory activities. The optimal extraction conditions found in this study were as follows: cellulase concentration 165.6 U/mL, temperature 57.3 °C, liquid-solid ratio 44.8 mL/g, time 50 min, and ultrasonic power 225 W; with the yield reached up to 12.27 %. The ion exchange and gel filtration chromatographies were used to obtain a purified SRP. The carbohydrate content of SRP was 85.09 %, with a relatively high content of uronic acids (11.27 %). The SRP had a molecular weight of 89.7 kDa and was composed of eight monosaccharides. The inhibitory activity of SRP against α-amylase and α-glucosidase was determined. It was revealed that SRP could effectively inhibit these two enzymes with IC₅₀ values of 1.23 and 0.63 mg/mL, respectively. Finally, the immunomodulatory effect of SRP on the dendritic cell activation was investigated, and the expressions of MHC II, CD80, CD86, and CD40 increased by 1.56, 1.96, 1.75, and 1.70 times, respectively, by the SRP treatment. This work will provide a foundation for SRP's efficient extraction and utilization for diabetes and immune therapy.

Therapeutic potential of non-starch polysaccharides on type 2 diabetes: from hypoglycemic mechanism to clinical trials

Non-starch polysaccharides (NSPs) have been reported to exert therapeutic potential on managing type 2 diabetes mellitus (T2DM). Various mechanisms have been proposed; however, several studies have not considered the correlations between the anti-T2DM activity of NSPs and their molecular structure. Moreover, the current understanding of the role of NSPs in T2DM treatment is mainly based on in vitro and in vivo data, and more human clinical trials are required to verify the actual efficacy in treating T2DM. The related anti-T2DM mechanisms of NSPs, including regulating insulin action, promoting glucose metabolism and regulating postprandial blood glucose level, anti-inflammatory and regulating gut microbiota (GM), are reviewed. The structure-function relationships are summarized, and the relationships between NSPs structure and anti-T2DM activity from clinical trials are highlighted. The development of anti-T2DM medication or dietary supplements of NSPs could be promoted with an in-depth understanding of the multiple regulatory effects in the treatment/intervention of T2DM.

Structural Characteristics, Antioxidant and Hypoglycemic Activities of Polysaccharide from Siraitia grosvenorii

The structural characterization, the in vitro antioxidant activity, and the hypoglycemic activity of a polysaccharide (SGP-1-1) isolated from Siraitia grosvenorii (SG) were studied in this paper. SGP-1-1, whose molecular weight is 19.037 kDa, consisted of Gal:Man:Glc in the molar ratio of 1:2.56:4.90. According to the results of methylation analysis, GC–MS, and NMR, HSQC was interpreted as a glucomannan with a backbone composed of 4)-β-D-Glcp-(1→4)-, α-D-Glcp-(1→4)-, and 4)-Manp-(1 residues. α-1,6 linked an α-D-Galp branch, and α-1,6 linked an α-D-Glcp branch. The study indirectly showed that SGP-1-1 has good in vitro hypoglycemic and antioxidant activities and that these activities may be related to the fact that the SGP-1-1’s monosaccharide composition (a higher proportion of Gal and Man) is the glycosidic-bond type (α- and β-glycosidic bonds). SGP-1-1 could be used as a potential antioxidant and hypoglycemic candidate for functional and nutritional food applications.

Separation, characterization and hypoglycemic activity in vitro evaluation of a low molecular weight heteropolysaccharide from the fruiting body of Phellinus pini

Edible mushrooms have potential in anti-diabetic phytotherapy. They are rich in natural compounds such as polysaccharides, which have been known to have antihyperlipidemic effects since ancient times. A polysaccharide fraction of PP80 and a contained low molecular-weight (Mw), water-soluble polysaccharide (PPW-1, Mw: 3.2 kDa) were isolated from the fruiting body of Phellinus pini. Both PP80 and PPW-1 possess α-glucosidase inhibition and glucose consumption amelioration in an insulin-resistant HepG2 cell model. The α-glucosidase inhibitory activity of PPW-1 (IC50 = 2.2 ± 0.1 mg mL-1) is significantly (P < 0.01) higher than those of PP80 (IC50 = 13.1 ± 0.5 mg mL-1) and acarbose (IC50 = 4.3 ± 0.2 mg mL-1), behaving in a non-competitive inhibition manner. The structural characterization results indicated that PPW-1 is a homogeneous heteropolysaccharide composed of d-glucose, d-mannose, d-galactose and l-rhamnose. The major backbone of PPW-1 is primarily comprised of 1,6-linked glucopyranose, every third residue of which is branched at the O-3 position by a side chain consisting of 1,3-linked and terminal glucopyranose. In addition, small amounts of 1,2-linked-α-d-Manp, 1,6-linked-3-O-Me-α-d-Galp and rhamnose exist in PPW-1. In summary, PPW-1 is a novel heteropolysaccharide with potent in vitro hypoglycemic activity, and it may be a potential dietary component for improving glucose homeostasis.

Preparation of phytic acid modified α-Glucosidase/Cu3(PO4)2·3H2O hybrid nanoflower and its application

A simple, convenient and efficient enzyme immobilization method through phytic acid (PA) modified α-Glucosidase (α-Glu)/Cu₃(PO₄)₂·3H₂O hybrid nanoflower was developed. The structural properties of the materials were studied by several characterization techniques. Subsequently, the enzymatic reaction conditions such as the pH value and temperature were optimized, and the enzyme kinetics and inhibition parameters were determined. The PA modified α-Glu/Cu₃(PO₄)₂·3H₂O hybrid nanoflower had better enzymatic activity under a wide pH range and high temperature than the free one. After seven successive cycles, the PA modified α-Glu/Cu₃(PO₄)₂·3H₂O hybrid nanoflower could still maintain approximately 63.0 % of its initial immobilized enzyme activity. The Michaelis-Menten constant (K_m) and the half-maximal inhibitory concentration (IC₅₀) of acarbose were determined as 0.77 mM and 15.01 μM, respectively. In addition, the material was applied to evaluate the inhibitory activity of ten phenolic compounds on α-Glu, and epicatechin gallate, gallocatechin gallate, epigallocatechin gallate and rosmarinic acid showed good inhibitory activity with % of inhibition of (53.42 ± 2.39)%, (37.28 ± 1.32)%, (37.08 ± 0.63)% and (35.53 ± 0.23)%, respectively. These results indicate that the PA modified hybrid nanoflower is an efficient method of α-Glu immobilization.

Structural characterization and inhibitions on α-glucosidase and α-amylase of alkali-extracted water-soluble polysaccharide from Annona squamosa residue

A novel acidic polysaccharide, named as AWPA, was extracted form Annona squamosa residue by 0.1 M NaOH alkaline solution and purified by DEAE-cellulose and Sephadex G-150. HPLC analysis indicated that AWPA was a homogeneous polysaccharide with molecular weight of 3.08 × 10³ kDa. The monosaccharide composition of AWPA, determined by ion chromatography, was consisted of L-arabinose, D-galactose, d-glucose, D-mannose, D-galacturonic acid in a percentage of 15.58:13.48:60.14:9.02:1.78, respectively. The results of FT-IR, methylation and NMR showed that the sugar residue of AWPA were mainly composed of α-L-Araf-(1→, →4)-α-D-Glcp-(1→, →4)-β-D-Galp-(1→, →6)-β-D-Glcp-(1→, →4,6)-β-D-Galp(1→, →3,6)-α-D-Manp-(1→, respectively. The Congo red experiment on AWPA showed that there was helix conformation. The microstructure of AWPA was detected by scanning electron microscopy, showing that the shape of AWPA was reticular and its structure was irregular. AWPA had effectively α-glucosidase inhibitory activity and α-amylase inhibitory activity with IC₅₀ of 0.667 mg/mL and 1.360 mg/mL, respectively. The inhibitory effects of AWPA on α-glucosidase and α-amylase were both reversible with mixed type and competitive type competition, respectively. The significance of manuscript was not only to avoid the waste of Annona squamosa residue, but provided alternative in the developments of inhibitors of α-glucosidase and α-amylase.

Inhibitory mechanism of sinensetin on α-glucosidase and non-enzymatic glycation: Insights from spectroscopy and molecular docking analyses

Inhibition of α-glucosidase and non-enzymatic glycation is regarded as an effective method to prevent and treat type 2 diabetes and its complications. In this study, the inhibition of sinensetin on α-glucosidase and non-enzymatic glycation was studied with multi-spectroscopic techniques and molecular docking analysis. The results of fluorescence spectroscopy analysis indicated that sinensetin quenched the endogenous fluorescence of α-glucosidase in static manner. The binding of sinensetin with α-glucosidase was a spontaneous process primarily driven by hydrophobic interaction. At 298 K, the binding constant was (5.70 ± 0.12) × 10⁴ L·mol^-1 and the binding site number was 1. The conformation of α-glucosidase was altered by sinensetin, which was revealed by circular dichroism (CD), FTIR spectra, synchronous fluorescence and three-dimensional (3D) fluorescence spectroscopy methods. Molecular docking analysis demonstrated that sinensetin interacted with the amino acid residues of α-glucosidase, which might prevent the entrance of substrate, leading to the decrease of catalytic efficiency of α-glucosidase. Furthermore, glycation assays showed that sinensetin stabilized the structure of bovine serum albumins (BSA), interacted with BSA, strongly inhibited the formation of dityrosine, N'-formylkynurenine and advanced glycation end products (AGEs). This study provided useful information concerning sinensetin preventing and treating type 2 diabetes and its related complications.

Structural characterization, α-amylase and α-glucosidase inhibitory activities of polysaccharides from wheat bran

In this study, two polysaccharide fractions were isolated from wheat bran by sequential extraction with water and alkaline solution, DEAE Cellulose-52 chromatography and Sephacryl S-400 gel permeation chromatography, they were named as WXA-1 and AXA-1, respectively. Structural analyses indicated that both polysaccharide fractions were heteropolysaccharides, their average molecular weights were 193 kDa and 107 kDa, respectively. The backbone of WXA-1 was → 4)-β-d-Xylp-(1→, which was substituted at O-3 positions by arabinose, glucose and galactose residues, while the backbone of AXA-1 was → 4)-β-d-Xylp-(1→, which was mainly substituted at O-3 positions by arabinose. AXA-1 exerted a stronger inhibitory effect on the activities of α-amylase and α-glucosidase compared with WXA-1. Moreover, AXA-1 exhibited a competitive inhibition of α-amylase and a mixed-type noncompetitive inhibition of α-glucosidase. These results suggest that AXA-1 can be used as α-amylase and α-glucosidase inhibitors.

Characterization of Polysaccharides Extracted from Pulps and Seeds of Crataegus azarolus L. var. aronia: Preliminary Structure, Antioxidant, Antibacterial, α-Amylase, and Acetylcholinesterase Inhibition Properties

Polysaccharides from the pulps (CAP) and seeds (CAS) of Crataegus azarolus L. var. aronia were extracted by hot water method. Both polysaccharides were characterized by scanning electron microscopy (SEM), Congo red test, FT-IR spectroscopy, and their antioxidant, α-amylase, antiacetylcholinesterase, and antibacterial activities were evaluated. CAP showed the highest total carbohydrate (82.35%) and uronic acid (29.39%) contents. The Congo red test revealed the lack of triple-helical conformation for both polysaccharides. The comparison of both infrared spectra indicated similar patterns with the presence of typical bands of polysaccharides. However, the microstructure of both samples indicated differences when analyzed by SEM. CAP displayed higher antioxidant, α-amylase, and acetylcholinesterase inhibitory activities. Besides, CAP showed the strongest antimicrobial effects against seven microorganisms and, notably, the Gram-positive bacteria. Overall, the results suggest that polysaccharides from C. azarolus L. var. aronia may be considered as novel sources of antioxidants and recommended as enzyme inhibitory agents in food and pharmaceutical industries.

Extraction, purification, characterization, anticoagulant activity, and anticoagulant mechanism of polysaccharides from the heads of Hypomesus olidus

The aim of this work was to extract, isolate, and purify polysaccharides from the heads of Hypomesus olidus and to evaluate their anticoagulant activities and anticoagulant mechanisms. Response surface methodology was used to optimize the extraction conditions for ultrasonic-assisted extraction of polysaccharides from the heads of Hypomesus olidus. The optimal extraction conditions consisted of ultrasonic power of 275 W, ultrasonic time of 50 min, and solid-liquid ratio of 5 ml/g, giving the yield of crude polysaccharides (GYT) of 7.73 ± 0.042%. Three polysaccharide fractions, GYT-1, GYT-2, and GYT-3 were purified from GYT by using DEAE-cellulose-52 column and Sephadex G-100 column for anticoagulant activities. The results showed that two doses (2 and 4 mg/ml) of GYT-1 and GYT-3 could significantly prolong (p < .01) in partial thromboplastin time (APTT) (2.19 and 2.37 times, 2.22 and 2.44 times, respectively) and thrombin time (TT) (2.39 and 2.46 times, 2.44 and 2.80 times, respectively) compared with normal control. In particular, GYT-3 had stronger anticoagulant activity than GYT-1, and it was composed of arabinose, fructose, glucose, and lactose with molar ratios of 0.595:1: 2.026:0.273. However, GYT-2 had no anticoagulant activity (p > .05). In addition, anticoagulation mechanism of polysaccharides from the heads of Hypomesus olidus (GYT-3) was evaluated. The results showed that the anticoagulant activity of GYT-3 was based on their binding with antithrombin AT-III. And the inhibitory effects of GYT-3 on factor IIa and Xa were related to the concentration of AT-III in plasma. This study may provide a new and promising anticoagulant drug.

Study on the extraction, purification, partial chemical characterization and anti-alcohol liver injury activity of Mori Fructus polysaccharides

Mori Fructus (MF) is a fruit rich in many nutrients.

Preparation, characterization, antioxidant and antiglycation activities of selenized polysaccharides from blackcurrant

An ultrasound-assisted enzymatic method was used to extract the polysaccharides from blackcurrant fruits (BP), and then a nitric acid-sodium selenite method was employed to prepare twelve kinds of selenized blackcurrant polysaccharides (SBPs). Among them, SBP-1, SBP-2 and SBP-3 with different selenium contents of 250 ± 11, 312 ± 15 and 643 ± 24 μg g⁻¹, displayed relatively higher 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙) scavenging activities than the others. After treating with a Sepharose-6B chromatography column, the purified blackcurrant polysaccharide (PBP) and three selenized polysaccharides (PSBP-1, PSBP-2, PSBP-3) with high purity were obtained. Compared with PBP, PSBPs possessed a larger absolute value of zeta potential (ZP) and smaller particle size, indicating the positive influence of selenized modification on physical stability of polysaccharides. Ultraviolet (UV), Fourier transform infrared (FT-IR) and circular dichroism (CD) spectra confirmed that selenium had been introduced onto the polysaccharide structure. X-ray diffraction (XRD) and I₂–KI reaction results indicated that selenized modification did not cause an obvious change in crystal form and branch structure of blackcurrant polysaccharides. In addition, PSBPs were superior to PBP in antioxidant and antiglycation capacities, and the bioactivities of PSBPs were significantly improved in positive correlation with selenium content. This study suggested that PSBPs may be a potential selenium source and serve as functional food and medicine.

An ultrasound-assisted enzymatic method was used to extract the polysaccharides from blackcurrant fruits (BP), and then a nitric acid-sodium selenite method was employed to prepare twelve kinds of selenized blackcurrant polysaccharides (SBPs).

Preparation, characteristics, and antioxidant activities of carboxymethylated polysaccharides from blackcurrant fruits

In the present study, the native polysaccharide (RNP) extracted from blackcurrant fruits was carboxymethylated. Physicochemical characteristics and antioxidant activities in vitro of RNP and three carboxymethylated polysaccharides (CRNPs) were determined. GC analysis proved that RNP and CRNPs were composed of the same six monosaccharides (galacturonic acid, rhamnose, arabinose, mannose, glucose and galactose), but the molar ratios of monosaccharides were different. HPLC demonstrated that the molecular weights of CRNPs were improved. The assays of the antioxidant properties indicated that CRNPs possessed stronger scavenging activities on radicals (hydroxyl and superoxide radicals) and better anti-lipid peroxidation activities, as well as better protection effects on erythrocyte hemolyses in vitro compared with RNP. The activities of CRNPs were significantly enhanced with the increase of the degree of substitution (DS). These results proved that the carboxymethylation could effectively increase the antioxidant activities of the polysaccharide.

GC-MS Analysis and Inhibitory Evaluation of Terminalia catappa Leaf Extracts on Major Enzymes Linked to Diabetes

Terminalia catappa leaves are used in managing both diabetes mellitus and its complications in Southwest Nigeria. However, its inhibitory activity on enzymes implicated in diabetes is not very clear. This study investigated the in vitro inhibitory properties and mode of inhibition of T. catappa leaf extracts on enzymes associated with diabetes. The study also identified some bioactive compounds as well as their molecular interaction in the binding pocket of these enzymes. Standard enzyme inhibition and kinetics assays were performed to determine the inhibitory effects of aqueous extract (TCA) and ethanol extract (TCE) of T. catappa leaves on α-glucosidase and α-amylase activities. The phytoconstituents of TCA and TCE were determined using GC-MS. Molecular docking of the phytocompounds was performed using Autodock Vina. TCA and TCE were the most potent inhibitors of α-glucosidase (IC₅₀ = 3.28 ± 0.47 mg/mL) and α-amylase (IC₅₀ = 0.24 ± 0.08 mg/mL), respectively. Both extracts displayed a mixed mode of inhibition on α-amylase activity, while mixed and noncompetitive modes of inhibition were demonstrated by TCA and TCE, respectively, on α-glucosidase activity. The GC-MS analytic chromatogram revealed the presence of 24 and 22 compounds in TCE and TCA, respectively, which were identified mainly as phenolic compounds, terpenes/terpenoids, fatty acids, and other phytochemicals. The selected compounds exhibited favourable interactions with the enzymes compared with acarbose. Overall, the inhibitory effect of T. catappa on α-amylase and α-glucosidase may be ascribed to the synergistic action of its rich phenolic and terpene composition giving credence to the hypoglycaemic nature of T. catappa leaves.

Antidiabetic activity of a polysaccharide-protein complex from Asian Clam (Corbicula fluminea) in streptozotoxin-induced diabetic rats and its underlying mechanism

Antidiabetic activity of a polysaccharide-protein complex from Asian Clam (Corbicula fluminea) in streptozotoxin-induced diabetic rats and its underlying mechanism.

Enzyme Assisted Extraction, Purification and Structure Analysis of the Polysaccharides from Naked Pumpkin Seeds

Enzyme assisted extraction was used to extract the polysaccharides from pumpkin seeds (PSP) and the extraction parameters were optimized by response surface methodology (RSM). Under the optimum experimental parameters: Extraction temperature of 60 °C, extraction time of 43 min, enzyme concentration of 2.5%, and pH of 6.0, the yield of PSP was 3.22 ± 0.04%, which was in close agreement with the predicted value (3.24%). After further purification on anion exchange column and gelfiltration column, a novel purified polysaccharide (PSPE) with molecular weight of 16,700 g/mol was obtained. PSPE was mainly composed of mannose, galactose and glucose in the molar ratio of 1.00:3.84:1.62. NMR spectra analysis showed that the major backbone of PSPE consisted of →4)-α-d-Glcp-(1→, →4)-β-d-Manp-(1→, →3,6)-β-d-Glap-(1→, and β-d-galactose.