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Microwave assisted aqueous two-phase system (MA-ATPS) was used to simultaneously extract two polysaccharides from blackcurrant. Under the suitable ATPS (ethanol/(NH 4 ) 2 SO 4 , 26.75 %/18.98 %) combining with the optimal MA conditions (liquid-to-material ratio 58.5 mL/g, time 9.5 min, temperature 60.5 °C, power 587 W) predicted by response surface methodology, the yields of the top/bottom phase polysaccharides were 13.08 ± 0.37 % and 42.65 ± 0.89 %, respectively. After purification through column chromatography, the top phase polysaccharide (PRTP) and bottom phase polysaccharide (PRBP) were obtained. FT-IR, methylation and NMR analyses confirmed that the repeating unit in the backbone of PRTP was →2, 5)-α-L-Araf-(1 → 3)-α-D-Manp-(1 → 6)-β-D-Galp-(1 → 6)-α-D-Glcp-(1 → 4)-α-L-Rhap-(1 → 4)-α-D-GalAp-(1→, while the possible unit in PRBP was →4)-α-L-Rhap-(1 → 3)-α-D-Manp-(1 → 6)-β-D-Galp-(1 → 6)-α-D-Glcp-(1 → 2, 5)-α-L-Araf-(1 → 4)-α-D-GalAp-(1→. PRBP with relatively low molecular weight exhibited better stability, rheological property, free radical scavenging and acetylcholinesterase (AChE) inhibitory activities than PRTP. PRTP and PRBP were reversible mixed-type inhibitors for AChE, and the conformation of AChE was changed after binding with the polysaccharides. Molecular docking, fluorescence and isothermal titration calorimetry assays revealed that PRTP and PRBP quenched the fluorescence through static quenching mechanism, and the van der Waals interactions and hydrogen bonding played key roles in the stability of polysaccharide-enzyme complexes. This study provided a theoretical basis for blackcurrant polysaccharides as AChE inhibitors to treat Alzheimer's disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The polysaccharide from Ribes nigrum L. (RCP) was modified by nitric acid-sodium selenite method. After purification by Sepharose-6B, high purity native (PRCP) and three selenized polysaccharides (PRSPs) with different selenium contents were obtained. Compared with PRCP, PRSPs possessed the lower molecular weight, better water-solubility, physical stability and rheological properties. FT-IR and NMR spectra confirmed PRSPs had the characteristic absorption peaks of polysaccharides and the glycosidic bond types were not changed after selenylation modification, whereas the selenyl groups existing in PRSPs were mainly introduced at the C-6 position of sugar residue →4)-β-d-Manp-(1→. Moreover, PRSPs displayed obviously smoother and smaller flaky structure than PRCP, and their inhibitory effects on α-amylase and α-glucosidase also were greater than PRCP. PRSPs exhibited a reversible inhibition on two enzymes in competitive manner and quenched their fluorescence through the static quenching mechanism. The polysaccharide-enzyme complex was spontaneously formed mainly driven by the hydrophobic interaction and hydrogen bonding., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this study, H 2 O 2 -Vc (hydrogen peroxide-ascorbic acid) oxidation system under 50 and 70 °C was developed to degrade blue honeysuckle polysaccharides. The results suggested that viscosity-average molecular weight was decreased and reducing sugar content was raised with the rise of time or temperature. The degradation was fitted to the second-order reaction kinetics. The gas chromatography revealed two degraded polysaccharides were consisted of six monosaccharides (Gal A, Rha, Ala, Gal, Glu, Man) with different ratios, and eight types of sugar residues were confirmed using nuclear magnetic resonance. Based on the linearity (R 1 ), branching (R 2 ), branch size (R 3 ) calculation, PD70 (purified degraded polysaccharide at 70 °C) had a more linear structure and longer side chains comparing to PD50 (purified degraded polysaccharide at 50 °C). The absence of triple helical structure and sheet-like aggregation with rough surface were confirmed by the Congo red test and scanning electron. Rheological characterization proved the two degraded polysaccharides exhibited shear-thinning behavior and viscoelastic property. Besides, the two degraded polysaccharides displayed strong antiglycation activities, inhibitory effects against α-amylase and α-glucosidase, and exhibited competitive inhibitory kinetics. These findings support the potential application of blue honeysuckle polysaccharides as the treatment of diabetes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The polysaccharides from blackcurrant (Ribes nigrum L.) fruits were degraded by ultrasonic irradiation. Results showed that viscosity-average molecular weight decreased with increasing ultrasonic time or power. The degradation was fitted to the second-order kinetics model and midpoint chain scission model. Gas chromatographic analysis demonstrated that the native polysaccharide and three degraded polysaccharides were composed of the same monosaccharides but in different ratios. Fourier transform infrared and nuclear magnetic resonance spectroscopic analyses revealed the presence of α-, β-pyranose rings and the same six sugar residues in the four blackcurrant polysaccharides. Compared to the native polysaccharide, three degraded polysaccharides displayed better rheological properties and stronger protective effects against erythrocyte hemolysis. Collectively, the results support the potential utility of blackcurrant polysaccharides as natural antioxidants., Competing Interests: Declaration of competing interest No conflict of interest exits in the submission of this manuscript., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Seabuckthorn fruits contains many active subtances, among them, the seabuckthorn polysaccharide is one of the main active ingredients, and exhibits diverse bioactivities. The extraction of polysaccharides from seabuckthorn fruits is the most important step for their wide applications. Ultrasound‐assisted aqueous two‐phase extraction (UA‐ATPE) is a promising green method for extracting polysaccharides. Additionally, physicochemical characterization and antioxidant activities can evaluate the potential functions and applications in the food and medicine industries. Results: Based on the single‐factor experiments, 20.70% (w/w) ammonium sulfate ((NH4)2SO4) and 27.56% (w/w) ethanol were determined as the suitable composition for aqueous two‐phase. The optimum conditions of UA‐ATPE obtained by response surface methodology were as follows: ultrasonic power (390 W), extraction time (41 min), liquid‐to‐material ratio (72: 1 mL/g), and the total yield of the polysaccharides reached 34.14 ± 0.10%, The molecular weights of the purified upper‐phase seabuckthorn polysaccharide (PUSP) and the purified lower‐phase seabuckthorn polysaccharide (PLSP) were 65 525 and 26 776 Da, respectively. PUSP and PLSP contained the same six monosaccharides (galacturonic acid, rhamnose, xylose, mannose, glucose and galactose), but with different molar ratios. Furthermore, PUSP and PLSP displayed certain viscoelastic property, had no triple helical structure, possessed different thermal stability, surface morphology and conformation in aqueous solution. PUSP and PLSP displayed strong antioxidant properties by the assays of scavenging ability of ABTS+·, the protection of DNA damage and erythrocyte hemolysis. Conclusion: UA‐ATPE significantly increased the yield of seabuckthorn polysaccharides. PUSP and PLSP were different in many aspects, such as molar ratio, surface shape and antioxidant activities. Seabuckthornpolysaccharides possess great potential in medicine and functional foods. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Natural polysaccharides are concerned for their high biological activity and low toxicity. Two kinds of polysaccharides were extracted from Hippophae rhamnoide L. by microwave-assisted aqueous two-phase system. Under the optimal conditions predicted by RSM model (K 2 HPO 4 /ethanol (18.93 %/28.29 %), liquid to material ratio 77 mL/g, power 625 W and temperature 61 °C), the yield of total polysaccharides reached 35.91 ± 0.76 %. Moreover, the polysaccharides extraction was well fitted to the Weibull model. After purification by Sepharose-6B, the polysaccharides from top phase (PHTP, purity of 81.44 ± 1.25 %) and bottom phase (PHBP, purity of 88.85 ± 1.40 %) were obtained. GC, FT-IR, methylation and NMR analyses confirmed the backbone of PHTP was composed of a repeated unit →4)- β -D-Glc p -(1 → 2)- α -L-Rha p -(1 → 4)- β -D-Gal p -(1 → 4)- α -D-GalA p -(1 → 3)- α -L-Ara f -(1 → 3)- α -D-Man p -(1→, while the repeated unit in PHBP was →3)- α -L-Ara f -(1 → 2)- α -L-Rha p -(1 → 4)- β -D-Glc p -(1 → 3)- α -D-Man p -(1 → 4)- β -D-Gal p -(1 → 4)- α -D-GalA p -(1→. Compared with PHTP (6.46 × 106 g/mol), PHBP with relatively low molecular weight (8.2 × 105 g/mol) exhibited the smaller particle size, better water-solubility, thermal and rheological property, stronger anti-glycosylation and α -amylase inhibitory effects. Moreover, PHTP and PHBP displayed a reversible inhibition on α -amylase in a competitive manner. This study provides a high-efficient and eco-friendly method for polysaccharides extraction, and lays a foundation for sea buckthorn polysaccharides as potential therapeutic agents in preventing and ameliorating diabetes. [Display omitted] • MA-ATPE of two polysaccharides from sea buckthorn fruits was optimized by RSM model. • There were different repeated units in the backbone structures of PHTP and PHBP. • PHBP exhibited better physical and thermal stability, rheological property than PHTP. • PHTP and PHBP were novel natural agents for preventing and ameliorating diabetes. [ABSTRACT FROM AUTHOR]

High pressure assisted aqueous two-phase system for simultaneous extraction of polysaccharides and polyphenols from Schisandra chinensis was modeled by response surface methodology (RSM) and artificial neural network (ANN). ANN displayed higher coefficient of determination (0.9725), and lower Pearson's Chi-square (0.2950), absolute average deviation (1.0693) and root means square error (0.6479) than RSM model (0.9440, 0.6231, 1.6725, 0.9666), indicating ANN had better prediction capability than RSM. Under suitable aqueous two-phase system (ethanol/ammonium sulfate, 29.37%/19.83%) combining with optimal high pressure conditions (liquid-to-material ratio 87.10 mL/g, pressure 4.78 MPa, temperature 60.92 °C, and time 16.01 min) predicted by ANN, the yields of polyphenols, polysaccharides, and DPPH radical scavenging activities were separately 1.87 ± 0.06 mg/g, 16.76% ± 0.52%, 95.04% ± 0.97% and 84.84% ± 1.48%, which were higher than the response values optimized by RSM (1.80 ± 0.60 mg/g, 16.19%±0.37%, 91.28% ± 1.92%, 83.19% ± 0.97%). After purification by column chromatography, the polyphenols in top phase (SCTP) and polysaccharides in bottom phase (SCBP) were obtained. Rutin, hyperoside, quercetin and veronicastroside were the main phenolic compounds in SCTP, which displayed strong antibacterial effects against foodborne pathogens. SCBP was an acidic heteropolysaccharide with a molecular weight of 6.46 × 106 g/mol, and showed potent protective effects against erythrocyte hemolysis. [Display omitted] • Polysaccharides and polyphenols were extracted from Schisandra chinensis by HP-ATPE. • ANN-GA-GRA was more superior than RSM for the optimization and prediction of HP-ATPE. • Rutin was the main ingredient in SCTP, while SCBP was an acidic heteropolysaccharide. • SCTP and SCBP separately showed potent antibacterial and antioxidant activities. [ABSTRACT FROM AUTHOR]

[Display omitted] • MA-ATPS can simultaneously extract polysaccharides and polyphenols from blackcurrant. • Ethanol/(NH 4) 2 SO 4 was best ATPS for active compounds extraction from blackcurrant. • Both RSM and ANN-GA-GRA models were used to predict and optimize MA-ATPE process. • ANN-GA-GRA was superior to RSM in predictability and data fittings for MA-ATPE. A procedure for simultaneous extraction of polysaccharides and polyphenols from blackcurrant fruits by microwave-assisted aqueous two-phase system (MA-ATPS) was studied. Ethanol/(NH 4) 2 SO 4 was determined as the most suitable ATPS including 18.99 % (NH 4) 2 SO 4 and 31.65 % of absolute ethanol. Apart from response surface methodology (RSM), artificial neural network linked genetic algorithms and grey relational analysis (ANN-GA-GRA) was also employed to optimize the extraction process of polysaccharides and polyphenols from blackcurrant fruits. GA was used to give assistance to the parameters optimization of ANN model and GRA was subsequently utilized to optimize the variables. ANN model displayed relatively higher coefficient of determination (R 2, 0.9805) and lower absolute average deviation (AAD, 0.6648) than those of RSM (R 2 = 0.9783, AAD = 0.8505), indicating ANN possessed more excellent prediction and estimation capabilities. Under the optimum conditions (liquid-to-material ratio, extraction time, extraction temperature and microwave power predicted by RSM were 60.01 mL/g, 9.96 min, 59.57 °C, and 592.98 W, while predicted by ANN were 56.10 mL/g, 9.78 min, 60.92 °C, and 640.78 W), the yields of polysaccharides, anthocyanins, polyphenols, and DPPH radical scavenging activities of two phases given by ANN (46.75 %, 6.75 mg/g, 53.51 mg/g, 95.17 %, and 97.05 %) were higher than those deriving from RSM (43.48 %, 6.62 mg/g, 52.48 mg/g, 93.72 %, and 96.65 %). In addition, gas chromatography (GC) analysis confirmed that the polysaccharides in bottom phase were composed of six monosaccharides, and thirteen phenolic compounds were determined in the extract of top phase by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). Therefore, microwave-assisted ethanol/(NH 4) 2 SO 4 extraction may be a promising technique to simultaneously prepare multiple active compounds from blackcurrant, and ANN-GA-GRA was an effective mathematical model to predict and optimize this extraction process. [ABSTRACT FROM AUTHOR]