Study on a novel spherical polysaccharide from Fructus Mori with good antioxidant activity

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.

Structural characterization and innate immunomodulatory effect of glucomannan from Bletilla striata

The crude polysaccharide of Bletilla striata in this study was extracted by water extraction and alcohol precipitation and further purified by gel column to yield the purified component Bletilla striata polysaccharide (BSP). Its structure and innate immune regulation activity were studied. BSP mainly comprises mannose and glucose, with a monosaccharide molar ratio of 2.9:1 and a weight-average molecular weight of 28,365 Da. It is a new low-molecular-weight water-soluble neutral glucomannan. BSP contains a → 6)-β-Manp-(1→, →4)-β-Glcp-(1→, →4)-β-Manp-(1 → and →3)-α-Manp-(1 → linear main chain, containing β-Glcp-(1 → and β-Manp-(1 → two branched chain fragments were connected to the Man residue at position 4. BSP can enhance the anti-infection ability of Caenorhabditis elegans against Pseudomonas aeruginosa, significantly improve the phagocytic ability of RAW264.7 macrophages, stimulate the secretion of NO and TNF-α, and have good innate immune regulation activity. These findings guide the use of Bletilla striata polysaccharides with immunomodulatory action.

The relationship between polysaccharide structure and its antioxidant activity needs to be systematically elucidated

Polysaccharides have a wide range of applications due to their excellent antioxidant activity. However, the low purity and unclear structure of polysaccharides have led some researchers to be skeptical about the antioxidant activity of polysaccharides. The current reports on the structure-activity relationship of polysaccharides are sporadic, so there is an urgent need to systematically summarize the antioxidant effects of polysaccharides with clear structures and the relationships between the structures to provide a scientific basis for the development and application of polysaccharides. This paper will systematically elucidate the structure-activity relationship of antioxidant polysaccharides, including the molecular weight, monosaccharide composition, glycosidic linkage, degree of branching, advanced conformation and chemical modification. For the first time, the antioxidant activity of polysaccharides is related to their chemical structure through histogram and radar map, and further studies using principal component analysis and cluster analysis. We critically discussed how the source, chemical structure and chemically modified groups of polysaccharides significantly contribute to their antioxidant activity and summarized the current research status and shortcomings of the structure-activity relationship of antioxidant polysaccharides. This review provides a theoretical basis and new perspective for further research on the structure-activity relationship of antioxidant polysaccharides and the development of natural antioxidants.

Structural characterization, chain conformation and immunomodulatory activity of a heteropolysaccharide from Inonotus hispidus

A new polysaccharide (IHP-1aa) was isolated from the fruiting body of Inonotus hispidus by hot water extraction, ethanol precipitation and column chromatography. The molecular weight of IHP-1aa was 26.9 kDa. Structural analysis showed that IHP-1aa consisted of glucose (Glc), galactose (Gal), fucose (Fuc), mannose (Man) and contained a certain amount of 3-O-methylgalactose (3-O-Me-Gal). The structure was mainly composed of →6)-α/β-D-Glcp-(1→, →6)-α-D-Galp-(1→, →6)-(3-O-Me)-α-D-Galp-(1→, →6)-α-D-Manp-(1 → and →2, 6)-α-D-Galp-(1 → as the main chain. Branched at O-2 with single β-L-Fucp-(1 → 6)-α-D-Galp-(1 → 6)-α-D-Glcp-(1 → as major the side chain. The results of SEM, XRD and AFM combined with Congo red indicated that IHP-1aa may be amorphous granular chain conformation. In addition, IHP-1aa stimulated macrophage function and improved phagocytic ability of RAW264.7, as well as promoted the secretion of NO, TNF-α and IL-6. IHP-1aa, a 3-O-methylgalactose-containing heteropolysaccharide, was isolated for the first time from the I. hispidus, which may be used as a potential immunomodulator in functional foods.

Comparative Study on the Impact of Different Extraction Technologies on Structural Characteristics, Physicochemical Properties, and Biological Activities of Polysaccharides from Seedless Chestnut Rose (Rosa sterilis) Fruit

Seedless chestnut rose (Rosa sterilis S. D. Shi, RS) is a fresh type of R. roxburghii Tratt with copious functional components in its fruit. Polysaccharides are recognized as one of the vital bioactive compounds in RS fruits, but their antioxidant and hypoglycemic properties have not been extensively explored. Hence, in this study, accelerated solvent extraction (RSP-W), citric acid (RSP-C), 5% sodium hydroxide/0.05% sodium borohydride (RSP-A), and 0.9% sodium chloride (RSP-S) solution extraction were individually utilized to obtain RS fruit polysaccharides. The physicochemical properties, structural characteristics, and biological activities were then compared. Results indicated that extraction methods had significant influences on the extraction yield, uronic acid content, monosaccharide composition, molecular weight, particle size, thermal stability, triple-helical structure, and surface morphology of RSPs apart from the major linkage bands and crystalline characteristics. The bioactivity tests showed that the RSP-S, which had the greatest amount of uronic acid and a comparatively lower molecular weight, exhibited more potent antioxidant and α-glucosidase inhibitory property. Furthermore, all RSPs inhibited α-glucosidase through a mixed-type manner and quenched their fluorescence predominantly via a static quenching mechanism, with RSP-S showing the highest binding efficiency. Our findings provide a theoretical basis for utilizing RSPs as functional ingredients in food industries.

The molecular mechanism of polysaccharides in combating major depressive disorder: A comprehensive review

Major depressive disorder (MDD) is a complex psychiatric condition with diverse etiological factors. Typical pathological features include decreased cerebral cortex, subcortical structures, and grey matter volumes, as well as monoamine transmitter dysregulation. Although medications exist to treat MDD, unmet needs persist due to limited efficacy, induced side effects, and relapse upon drug withdrawal. Polysaccharides offer promising new therapies for MDD, demonstrating antidepressant effects with minimal side effects and multiple targets. These include neurotransmitter, neurotrophin, neuroinflammation, hypothalamic-pituitary-adrenal axis, mitochondrial function, oxidative stress, and intestinal flora regulation. This review explores the latest advancements in understanding the pharmacological actions and mechanisms of polysaccharides in treating major depression. We discuss the impact of polysaccharides' diverse structures and properties on their pharmacological actions, aiming to inspire new research directions and facilitate the discovery of novel anti-depressive drugs.

Lonicerae flos polysaccharides improve nonalcoholic fatty liver disease by activating the adenosine 5'-monophosphate-activated protein kinase pathway and reshaping gut microbiota

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver cirrhosis and cancer. Lonicerae flos polysaccharides (LPs) have been shown to be effective in treating metabolic diseases; however, the therapeutic effects and underlying molecular mechanisms of LPs in NAFLD remain unclear.

PURPOSE

The objective of this study was to investigate the morphological characterization of Lonicerae flos polysaccharides (LPs) and the mechanism of LPs in relieving NAFLD.

METHODS

The morphology of LPs was observed using atomic force microscopy (AFM), X-ray diffraction (XRD), thermal weight (TG), and thermal weight derivative (DTG); NAFLD mice were treated with LPs at the same time as they were induced with a Western diet, and then the indexes related to glycolipid metabolism, fibrosis, inflammation, and autophagy in the serum and liver of the mice were detected.

RESULTS

The atomic force microscope analysis results indicated that the LPs displayed sugar-chain aggregates, exhibited an amorphous structure, and were relatively stable in thermal cracking at 150 °C. It was also found that LPs exerted therapeutic effects in NAFLD. The LPs prevented high-fat and -cholesterol diet-induced NAFLD progression by regulating glucose metabolism dysregulation, insulin resistance, lipid accumulation, inflammation, fibrosis, and autophagy. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor compound C abrogated LP-induced hepatoprotection in mice with NAFLD. The LPs further treated NAFLD by reshaping the structure of the gut microbiota, in which Desulfovibrio bacteria plays a key roles.

CONCLUSION

Lonicerae flos polysaccharides exert protective effects against NAFLD in mice by improving the structure of the intestinal flora and activating the AMPK signaling pathway. © 2023 Society of Chemical Industry.

Preparation of a new resource food-arabinogalactan and its protective effect against enterotoxicity in IEC-6 cells by inhibiting endoplasmic reticulum stress

Plant polysaccharides can be used as bioactive natural polymers that provide health benefits, however high molecular weight neutral polysaccharides have not shown good bioactivity. In this study, high molecular weight neutral arabinogalactan was isolated and structurally characterized to investigate it antioxidant activity against IEC-6 cells. In this study, a neutral polysaccharide (AG-40-I-II) was obtained from the roots of Larix gmelinii (Rupr.) Kuzen. and purified using ethanol fractional precipitation and purification on a DEAE-52 cellulose column and a Superose 12 gel filtration column. The structural characteristics of AG-40-I-II was detected by chemical and spectroscopic methods. The results showed that the average molecular weight of AG-40-I-II was 18.6 kDa, the main chain was composed of →4)-β-D-Gal-(1, → 4, 6)-β-D-Gal-(1 and →4)-β- D-Glc-(1, the side chain is composed of T-β-L-Araf(1 → 6). The effect of AG-40-I-II on H2O2-induced IEC-6 cell injury was determined by MTT method. Besides, AG-40-I-II could reduce the level of MDA and increase SOD activity on IEC-6 cells, which could significantly inhibit the production of ROS. Importantly, AG-40-I-II inhibited the splicing of XBP1 by IRE1α through the ERS pathway and reduced the cell apoptosis induced by H2O2. In summary, the results of this study indicate that AG-40-I-II, as a natural source of plant polysaccharides, has good antioxidant activity, and is expected to become a safe plant source of natural antioxidants, which has great potential in biomedicine potential.

Polysaccharides extracted from mulberry fruits (Morus nigra L.): antioxidant effect of ameliorating H2O2-induced liver injury in HepG2 cells

BACKGROUND

Mori Fructus is an economical and readily available traditional Chinese medicine and food. Polysaccharides in Mori Fructus have clear antioxidant activity and have been found to alleviate oxidative stress (OS)-induced liver damage in experimental studies. The mechanism of regulation of cellular antioxidant activity by mulberry polysaccharides has been suggested to be Nrf2, but it is not clear whether the Nrf2 pathway is mediated by activation of other targets, and the exact process of effects in hepatocytes has yet to be elucidated.

METHODS

In this study, the basic characterization of total polysaccharides extracted from mulberry fruits (Morus nigra Linn.) was analyzed. A model of oxidative damage induced by H₂O₂ in HepG2 cells was established. The levels of cellular oxidation-related markers, including ROS, SOD and Gpx, were then examined. Furthermore, Q-PCR and Western-blot were used to detect the expression of genes and proteins related to the PI3K/Akt-mediated Nrf2 signaling pathway.

RESULTS

The results showed that a total mulberry polysaccharides (TMP) has a molecular weight of 57.5 kDa with a pyranose ring mainly composed of glucose (48.81%), galactose (22.79%) and mannose (18.2%). TMP reduced the accumulation of ROS in HepG2 cells after H₂O₂ treatment and modulated the activity of SOD and Gpx. Q-PCR and Western-blot showed that TMP could up-regulate the expression of p-PI3K, p-AKT, Nrf2, NQO1 and HO-1.

CONCLUSIONS

This study demonstrates that TMP can reduce ROS accumulation in H₂O₂-treated HepG2 cells and restore cell viability by activating the PI3K/AKT-mediated Nrf2 pathway. TMP may be a potent antioxidant agent that could slow down oxidative damage to the liver.

Mori fructus aqueous extracts attenuates liver injury by inhibiting ferroptosis via the Nrf2 pathway

BACKGROUND

Liver fibrosis and hepatocellular carcinogenesis secondary to liver fibrosis are serious liver diseases with no effective treatments. Mori fructus aqueous extracts (MFAEs) have served as successful treatments for many types of liver injury including fibrosis although the molecular mechanisms are unknown at present.

PURPOSE

To investigate the effect of MFAEs in alleviating acute and chronic liver injury and tried to decipher the underlying mechanism.

METHODS AND RESULTS

Mice were divided into 5 groups (n = 8) for acute (groups: control, 0.3% CCl₄, bifendate (BD), 100 and 200 mg/kg MFAEs, 7 d) and chronic (groups: control, 10% CCl₄, BD, 100 and 200 mg/kg MFAEs, 4 weeks) liver injury study. Each mouse was injected intraperitoneally with 10 µL/g corn oil containing CCl₄ expect the control group. HepG2 cells were used in vitro study. Eighteen communal components were identified by UPLC-LTQ-Orbitrap-MS. We utilized a mouse model for acute and chronic liver injury using CCl₄ and MFAEs administration effectively blocked fibrosis and significantly inhibited inflammation in the liver. MFAEs activated the nuclear factor erythroid derived 2 like 2/heme oxygenase 1 (Nrf2/HO-1) pathway and promoted the synthesis of the antioxidants glutathione (GSH), superoxidedismutase (SOD) and glutathione peroxidase (GSH-Px) that resulted in reduced levels of CCl₄-induced oxidative stress molecules including reactive oxygen species. These extracts administered to mice also inhibited ferroptosis in the liver by regulating the expression of Acyl-CoA synthetase long chain family member 4 (ACSL4), solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), thus reducing the occurrence of liver fibrosis. Both in vivo and in vitro tests indicated that the mechanism of MFAEs protection against liver fibrosis was linked to activation of Nrf2 signaling. These effects were blocked in vitro by the addition of a specific Nrf2 inhibitor.

CONCLUSION

MFAEs inhibited oxidative stress, ferroptosis and inflammation of the liver by activating Nrf2 signal pathway and provided a significant protective effect against CCl₄-induced liver fibrosis.

Polysaccharide-Based Composite Scaffolds for Osteochondral and Enthesis Regeneration

The rotator cuff and Achilles tendons along with the anterior cruciate ligament (ACL) are frequently injured with limited healing capacity. At the soft-hard tissue interface, enthesis is prone to get damaged and its regeneration in osteochondral defects is essential for complete healing. The current clinical techniques used in suturing procedures to reattach tendons to bones need much improvement for the generation of the native interface tissue, that is, enthesis, for patients to regain their full functions. Recently, inspired by the composite native tissue, much effort has been made to fabricate composite scaffolds for enthesis tissue regeneration. This review first focuses on the studies that used composite scaffolds for the regeneration of enthesis. Then, the use of polysaccharides for osteochondral tissue engineering is reviewed and their potential for enthesis regeneration is presented based on their supporting effects on osteogenesis and chondrogenesis. Gellan gum (GG) is selected and reviewed as a promising polysaccharide due to its unique osteogenic and chondrogenic activities that help avoid the inherent weakness of dissimilar materials in composite scaffolds. In addition, original preliminary results showed that GG supports collagen type I production and upregulation of osteogenic marker genes. Impact Statement Enthesis regeneration is essential for complete and functional healing of tendon and ligament tissues. Current suturing techniques to reattach the tendon/ligament to bones have high failure rates. This review highlights the studies on biomimetic scaffolds aimed to regenerate enthesis. In addition, the potential of using polysaccharides to regenerate enthesis is discussed based on their ability to regenerate osteochondral tissues. Gellan gum is presented as a promising biopolymer that can be modified to simultaneously support bone and cartilage regeneration by providing structural continuity for the scaffold.

Comparative study on the extraction efficiency, characterization, and bioactivities of Bletilla striata polysaccharides using response surface methodology (RSM) and genetic algorithm-artificial neural network (GA-ANN)

This research established the optimal conditions for alkali-assisted extraction (AAE) of bioactive polysaccharides from Bletilla striata integrated with response surface methodology (RSM) and the genetic algorithm-artificial neural networks (GA-ANN). In comparison with RSM, the ANN model showed a relatively higher determination coefficient in the global output values (RSM: ANN = 0.9270: 0.9742) performing more satisfactorily in the validation. Under the optimum conditions (52 °C; 167 min, and 0.01 mol/L NaOH), the extraction yields, IC₅₀ of ABTS, and FRAP value were 29.53 ± 0.97 %, 3.41 mg/mL, and 39.11 μmol Fe²⁺/g, respectively. The results indicated that BSPs-A was mainly composed of glucose and mannose with small amounts of arabinose, galactose, and galacturonic acid, while possessed a molecular weight of about 305.94 kDa (Mw). The structural characterization of BSPs-A was initially characterized by FT-IR, SEM, and Congo red tests, which indicated that BSPs-A possessed a triple helix conformation of typical Bletilla striata polysaccharides. In addition, BSPs-A exhibited excellent antioxidant activity, which was further confirmed by a series of in vitro antioxidant activity assays including DPPH, ABTS, FRAP, and ORAC. After incubation in the BSA-glucose system for 15 days, BSPs-A showed inhibition of the advanced glycation end products (AGEs) formation for the first time.

Morus alba fruits attenuates atopic dermatitis symptoms and pathology in vivo and in vitro via the regulation of barrier function, immune response and pruritus

BACKGROUND

Morus alba fruits (MAF) belong to the Moraceae family, which are known to be effective in treating diabetic, autoimmune, and hormonal diseases owing to its low toxicity. MAF, as excerpted from Donguibogam, a representative Korean medical encyclopedia protected by UNESCO, has been widely used to treat lumbago, arthritis, and diabetes. Based on these effects, MAF is investigated for unidentified effects of atopic dermatitis, characterized by complex etiology of skin barrier dysfunction, inflammation, and chronic pruritus.

METHODS

The antioxidant, inflammatory, and immunomodulatory properties of MAF and its bioactive compounds have been widely reported. According to an examination of 1-chloro-2,4-dinitrobenzene-induced AD-like skin lesions in NC/Nga mice, AD symptoms, such as increased dermatitis score, scratching frequency, immunoglobulin E, trans-epidermal water loss, epidermal thickness, and infiltration of mast cells, were relieved by topical MAF administration. They effectively attenuated cytokines and chemokines, such as interleukin (IL)-4, IL-5, IL-6, IL-8, IL-13, IL-17A, IL-22, IL-1β, tumor necrosis factor-α, thymic stromal lymphopoietin (TSLP), thymic- and activation-regulated chemokine, normal T cell expression, and macrophage-derived chemokine secretion at the mRNA level in TNF-α/IFN-γ induced HaCaT (human immortalized keratinocyte) cells.

RESULTS

Both in vivo and in vitro models, MAF increased the expression of filaggrin, involucrin, and loricrin, as well as inhibited the activation of Janus kinase 2, signal transducer and activator of transcription proteins 1, and mitogen-activated protein kinase pathways, including extracellular signal-regulated kinase, c-jun N-terminal kinase, and p38. Moreover, MAF reduced the expression of TSLP and periostin, which play important roles in skin pruritus as chronic pruritogenic factors.

CONCLUSION

These data indicate that MAF could be used as a potential treatment for AD-like skin lesions by regulating the inflammatory response, improving physical skin barriers, and relieving symptomatic pruritus.

Production, characterization and antioxidant activity of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1

At present, the study on exopolysaccharid is mainly focused on lactic acid bacteria, and the research on exopolysaccharide produced by yeast, especially Sporidiobolus pararoseus, is relatively few. Therefore, the aim of this study was to explore the characterization and antioxidant activities of a novel neutral exopolysaccharide SPZ, which was isolated and purified from S. pararoseus PFY-Z1. The results showed that SPZ was mainly composed of mannose, followed by glucose, with a molecular weight was 24.98 kDa, had O-glycosidic bonds, no crystalline, and no triple helix structure. Based on fourier transform-infrared, high-performance liquid chromatography and nuclear magnetic resonance analyses, SPZ was identified to be a exopolysaccharide with some side chains, presence of α-, β-pyranose ring and nine sugar residues. Furthermore, the morphology features of SPZ have performed a relatively rough and uneven surface, covered with small pores and fissures. Moreover, SPZ had higher antioxidant activities and the maximum scavenging abilities of ⋅OH, NO₂^- and reducing power were 28.05 ± 0.73%, 92.76 ± 1.86% and 0.345 ± 0.024, respectively. Hence, SPZ could be used as a potential antioxidant application in the food and pharmaceutical industries.

Mori fructus aqueous extracts attenuate carbon tetrachloride-induced renal injury via the Nrf2 pathway and intestinal flora

Mori fructus aqueous extracts (MFAEs) have been used as a traditional Chinese medicine for thousands of years with the function of strengthening the liver and tonifying the kidney. However, its inner mechanism to alleviative renal injury is unclear. To investigate the attenuation of MFAEs on nephrotoxicity and uncover its potential molecular mechanism, we established a nephrotoxicity model induced by carbon tetrachloride (CCl₄). The mice were randomly divided into control group, CCl₄ model group (10% CCl₄), CCl₄ + low and high MFAEs groups (10% CCl₄ + 100 mg/kg and 200 mg/kg MFAEs). We found that MFAEs decreased the kidney index of mice, restored the pathological changes of renal structure induced by CCl₄, reduced cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (Kim-1) blood urea nitrogen and creatinine contents in serum, promoted the nuclear transportation of Nrf2 (nuclear factor erythroid derived 2 like 2), elevated the expression of HO-1 (heme oxygenase 1), GPX4 (glutathione peroxidase 4), SLC7A11 (solute carrier family 7 member 11), ZO-1 (zonula occludens-1) and Occludin, suppressed the expression of Keap1 (kelch-like ECH-associated protein 1), HMGB1 (High Mobility Group Protein 1), ACSL4 (acyl-CoA synthetase long chain family member 4) and TXNIP (thioredoxin interacting protein), upregulated the flora of Akkermansia, Anaerotruncus, Clostridium_sensu_stricto, Ihubacter, Alcaligenes, Dysosmobacter, and downregulated the flora of Clostridium_XlVa, Helicobacter, Paramuribaculum. Overlapped with Disbiome database, Clostridium_XlVa, Akkermansia and Anaerotruncus may be the potential genera treated with renal injury. It indicated that MFAEs could ameliorate kidney injury caused by CCl₄ via Nrf2 signaling.

Optimization of Extraction Process, Structure Characterization, and Antioxidant Activity of Polysaccharides from Different Parts of Camellia oleifera Abel

The flowers, leaves, seed cakes and fruit shells of Camellia oleifera are rich in bioactive polysaccharides, which can be used as additives in food and other industries. In this study, a Box-Behnken design was used to optimize the extraction conditions of polysaccharides from C. oleifera flowers (P-CF), leaves (P-CL), seed cakes (P-CC), and fruit shells (P-CS). Under the optimized extraction conditions, the polysaccharide yields of the four polysaccharides were 9.32% ± 0.11 (P-CF), 7.57% ± 0.11 (P-CL), 8.69% ± 0.16 (P-CC), and 7.25% ± 0.07 (P-CS), respectively. Polysaccharides were mainly composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and xylose, of which the molecular weights ranged from 3.31 kDa to 128.06 kDa. P-CC had a triple helix structure. The antioxidant activities of the four polysaccharides were determined by Fe2+ chelating and free radical scavenging abilities. The results showed that all polysaccharides had antioxidant effects. Among them, P-CF had the strongest antioxidant activity, of which the highest scavenging ability of DPPH•, ABTS•+, and hydroxyl radical could reach 84.19% ± 2.65, 94.8% ± 0.22, and 79.97% ± 3.04, respectively, and the best chelating ability of Fe2+ could reach 44.67% ± 1.04. Overall, polysaccharides extracted from different parts of C. oleifera showed a certain antioxidant effect, and could be developed as a new type of pure natural antioxidant for food.

Synthesis of naphthalimide-type chemsensor and its application in quality evaluation for polygonatum sibiricum Red

The premise and key of ensuring the safety and effectiveness of traditional Chinese medicine (TCM) is to construct appropriate quality evaluation system of TCM. This study aimed to establish a pre-column derivatization HPLC method for achieving the quality control of Polygonatum sibiricum by reacting synthesized 4-hydrazino-1,8-naphthalimide (HAN) with diverse monosaccharides from the hydrolytic product of P. sibiricum polysaccharides (PSPs), followed by HPLC separation. The HAN was synthesized based on a CuI-catalyzed cross-coupling reaction in water, and then employed as a novel chemosensor that reacts with reducing sugars. Good separation was achieved at a detection wavelength of 448 nm using an ZORBAX SB-C8 column under a gradient elution at a flow rate of 0.5 ml/min within 12 min. The monosaccharide compositions of PSP mainly include two hexoses [glucose (Glc), galactose (Gal)] and two hexuronic acids [glucuronic acid (GlcA) and galacturonic acid (GalA)], and the molar ratio of Glc, Gal, GlcA and GalA is 16.67:52.94:10.58:19.81. The verified HPLC method, possessing excellent precision and good accuracy, successfully achieved rapid qualitative and quantitative determination for PSP. Additionally, the HAN displayed fluorescence enhancement through “push–pull” mode, and fluorescence decreased through “pull–pull” mode after binding to monosaccharides, which is a potential for fluorescence determination of different monosaccharides.

Structural characterization and anti-osteoporosis activity of two polysaccharides extracted from the rhizome of Curculigo orchioides

Curculigo orchioides is widely used to treat osteoporosis in China. In this study, we identified the active substances in the crude polysaccharide (CO50) from C. orchioides that had anti-osteoporosis activity in vivo. Two polysaccharides, COP50-1 and COP50-4, were purified from CO50. Based on structural analysis, COP50-1 was composed of α-D-Glcp-(1→, β-D-Galp-(1→, →4)-α-D-Glcp-(1→, →3,4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, →4,6)-β-D-Manp-(1→, whereas COP50-4 was composed of α-L-Araf-(1→, →2)-α-L-Rhap-(1→, β-D-Manp-(1→, α-D-Galp-(1→, →2,4)-α-L-Rhap-(1→, →2)-β-D-Manp-(1→, →4)-α-D-GlcAp-(1→, →3)-α-D-GalAp-(1→, →4,6)-α-D-Galp-(1→, →2,3,6)-β-D-Manp-(1→, →2,3,5)-α-L-Araf-(1→, →2,5)-α-L-Araf-(1→, →4)-α-D-Glcp-(1→ and →3)-α-D-Galp-(1→. Pharmacological assessment revealed that COP50-1 had no obvious osteogenic activity. However, COP50-4 (0.5 μM) significantly enhanced the differentiation and mineralization of osteoblasts in vitro. Moreover, the effect of COP50-4 was greater than that of 17β-estradiol. Therefore, COP50-4 may be an effective component of CO50 that has great potential for development as an alternative drug for the treatment of osteoporosis.

Selenium-containing polysaccharides isolated from Rosa laevigata Michx fruits exhibit excellent anti-oxidant and neuroprotective activity in vitro

Selenium-containing polysaccharides have potential as an organic selenium dietary supplement, owing to their low toxicity, few side effects, and easy absorption attributes. In this study, we isolated two novel homogeneous selenium-containing polysaccharides from Rosa laevigata Michx fruits (Se-RLFPs). Results from primary structural analysis revealed that Se-RLFPs were α - pyranose, and were both composed of rhamnose, xylose, glucose with an average molecular weight of 24 and 16 KDa, respectively. Selenium contents in Se-RLFP-I and Se-RLFP-II were 16.49 μg/g and 21.61 μg/g, respectively. Results from analysis of antioxidant and neuroprotective activity of the polysaccharides revealed that Se-RLFPs had a radical scavenging effect. Specifically, they effectively protected SH-SY5Y cells from H₂O₂-induced damage by enhancing antioxidant enzyme activities (SOD), total antioxidant capacity (T-AOC) and suppressing malondialdehyde (MDA) levels. Western blots showed that the underlying mechanisms of action may be related to the Nrf2/HO-1 signaling pathway. Taken together, these results suggested that Se-RLFPs have potential as a pharmaceutical agent for treatment of neurodegenerative diseases (NDDs) or as a selenium-complementary ingredient in functional foods.

Study on the pharmacokinetics of mulberry fruit polysaccharides through fluorescence labeling

A sensitive and efficient fluorescence labeling method was developed and validated for the microanalysis and detection of polysaccharides. Fluorescein isothiocyanate (FITC) was successfully labeled on mulberry fruit polysaccharides (MFP) through a reductive amination reaction with the assistant of tyramine. The fluorescent labeled polysaccharides (FMFP) was identified by fluorescence, UV-visible, flourier transform infrared (FT-IR) and 1H NMR spectrum. Results demonstrated that the labeling efficiency of FMFP was 0.32%, and the FMFP was stable in simulated digestion fluid without cytotoxicity. The pharmacokinetics and biodistribution after administration were analyzed in rats, which indicated that the FMFP obtained could be absorbed in a short time (tmax 0.50 h) but eliminated slowly (t1/2 8.77 ± 1.38 h). At 24 h after administration, the polysaccharide could be tested mainly in intestine, stomach, liver and kidney. The FITC labeling method lays a foundation for investigating the absorption and metabolism of MFP, and provides references for the microanalysis research of bioactive polysaccharides.

The structure, conformation, and hypoglycemic activity of a novel heteropolysaccharide from the blackberry fruit

A novel heteropolysaccharide fraction (BBP-24-3) with a relative molecular weight of 145.1 kDa was isolated from blackberry fruits. The BBP-24-3 was mainly composed of arabinose, glucose, and galacturonic acid with a ratio of 5.30 : 3.60 : 91.10 mol%. Structural analysis showed that BBP-24-3 possessed a 1,6-linked β-d-Glcp, 1, 2, 3, 5 linked α-l-Araf, and 1, 4 linked α-d-GalpA backbone with branches substituted at the C-2 and C-5 positions of arabinose units, which included 1, 2, 3, 4 linked β-d-Glcp and T-linked β-d-GalpA. The conformation analysis indicated that BBP-24-3 exhibited a solid spherical structure with a uniform distribution in 0.1 M NaCl solution. The BBP-24-3 exhibited excellent α-glucosidase inhibitory activity with an IC50 value of 3.70 mg mL-1, which was due to the structural change, including α-helix and random coil of α-glucosidase caused by BBP-24-3. The current work suggests the potential utilization of BBP-24-3 as an α-glucosidase inhibitor in healthy food for reducing the postprandial blood glucose level.