Characterization of a new heteropolysaccharide from green guava and its application as an α-glucosidase inhibitor for the treatment of type II diabetes

Structural characteristics and potential antidepressant mechanism of a water-insoluble β-1,3-glucan from an edible fungus Wolfiporia cocos

A water-insoluble β-1,3-glucan (Wβ) with a molecular weight of 8.12 × 104 Da was extracted from an edible fungus Wolfiporia cocos. Its backbone was composed of 1,3-β-linked Glcp branched at the C-2, C-4, and C-6 positions, connecting more 1,3-β-linked Glcp with a triple helical structure. Wβ effectively ameliorated depressive symptoms, abnormality of neurotransmitters and inflammatory factors in chronic unpredictable mild stress (CUMS)-induced rats. Wβ also altered the composition of gut microbiota, especially Romboutsia, norank_f_Muribaculaceae and Ruminococcus. Integration of untargeted and targeted metabolomics and Western blotting analysis suggested that the short-chain fatty acids (SCFAs) and tryptophan metabolites were the most important metabolites involved in Wβ mediation. Wβ significantly modulated the levels of 7 SCFAs and 7 tryptophan metabolites, as well as the protein expression of two related enzymes (indoleamine-2,3-dioxygenase: IDO; kynurenine-3-monooxygenase: KMO). Our results suggest that Wβ exerts its antidepressant effect by influencing neurotransmitters and inflammatory factors through interactions between the gut microbiota, SCFA and tryptophan metabolites. The findings offer new insights into water-insoluble polysaccharides, especially β-glucan in structure analysis and utilization, and provide evidence that Wβ, a novel glucan from the often-discarded water-insoluble part of Wolfiporia cocos, has potential application in antidepressant health products.

A water-soluble mycelium polysaccharide from Monascus pilosus: Extraction, structural characterization, immunomodulatory effect and yield enhanced by overexpression of UGE gene

Mycelium polysaccharide (MPP) from Monascus pilosus with the compositions of glucose, galactose, mannose, glucosamine hydrochloride, rhamnose and arabinose, was obtained using alkaline extracting, and subsequently three purified components (MPP-0, MPP-0.1 and MPP-0.3) were separated. The purity and extraction volume of the MPP-0.1 fraction surpassed those of the other two groups, thus warranting its selection for subsequent experimental investigations. The sample MPP-0.1, with an average molecular weight of 3.7776 × 104 Da, exhibited exceptional thermal stability up to 170 °C. The main glycosidic linkage pattern of MPP-0.1 was structured as→[4)-α-D-Glcp-(1]6 → 4)-α-D-Glcp-(1 → [2)-α-D-Manp-(1]5 → 2)-α-D-Manp-(1 → 5)-β-D-Galf-(1 → 3)-β-D-Galf (1 → 3)-β-D-Galf-(1 → 3)-β-D-Galf-(1→, and branched Glcp, Manp, Galf fragments were connected with the main chain through →4, 6)-α-D-Glcp-(1→, →2, 6)-α-D-Manp-(1 → and →3, 6)-β-D-Galf-(1→. Besides, the up-regulated levels of Nitric oxide (NO), Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and other pro-inflammatory cytokines along with increased phagocytic activity revealed that MPP-0.1 has significant immunomodulatory effect, and can significantly enhance the proliferation and activation of RAW264.7 cells. Finally, the gene UGE (UDP-glucose 4-epimerase) was overexpressed in M. pilosus to increase the MPP production. Results showed that the biomass of the recombinant strain exhibited a remarkable increase of approximately 62.56 ± 1.50 % compared to that of the parental strain, and the extraction yield of MPP increased significantly by 83.19 ± 4.56 %.

A review: Polysaccharides targeting mitochondria to improve obesity

Polysaccharides are one of the most important and widely used bioactive components of natural products, which can be used to treat metabolic diseases. Natural polysaccharides (NPs) have been the subject of much study and research in the field of treating obesity in recent years. Studies in the past have demonstrated that mitochondria are important for the initiation, progression, and management of obesity. Additionally, NPs have the ability to improve mitochondrial dysfunction via a variety of mechanisms. This review summarized the relationship between the structure of NPs and their anti-obesity activity, focusing on the anti-obesity effects of these compounds at the mitochondrial level. We discussed the association between the structure and anti-obesity action of NPs, including molecular weight, monosaccharide composition, glycosidic linkage, conformation and extraction methods. Furthermore, NPs can demonstrate a range of functions in adipose tissue, including but not limited to improving the mitochondrial oxidative respiratory chain, inhibiting oxidative stress, and maintaining mitochondrial mass homeostasis. The purpose of this work is to acquire a thorough understanding of the function that mitochondria play in the anti-obesity effects of NPs and to offer fresh insights for the investigation of how NPs prevent obesity and the creation of natural anti-obesity medications.

Guava polysaccharides attenuate high fat and STZ-induced hyperglycemia by regulating gut microbiota and arachidonic acid metabolism

This study investigated the hypoglycemic mechanism of guava polysaccharides (GP) through the gut microbiota (GM) and related metabolites. Our findings demonstrated that GP significantly mitigated high-fat diet- and streptozotocin-induced hyperglycemia, insulin resistance, hyperlipidemia, elevated alanine aminotransferase, high hepatic inflammation levels, and prevented pancreatic atrophy and hepatomegaly. Interestingly, the benefits of GP were attributed to alterations in the GM. GP decreased the ratio of Firmicutes to Bacteroidetes, significantly inhibiting deleterious bacteria, including Uncultured_f_Desulfovibrionaceae, Bilophila, and Desulfovibrio, while promoting the proliferation of probiotic Bifidobacterium and Bacteroides. In addition, GP promoted the generation of short-chain fatty acids. Notably, the arachidonic acid (AA) metabolism pathway was enriched in liver metabolites. GP significantly elevated hepatic AA and 15-hydroxyeicosatetraenoic acid, while reducing prostaglandin E2 and 5- and 12-hydroxyeicosatetraenoic acid. This modulation is accompanied by the downregulation of hepatic cyclooxygenase-1, 12-lipoxygenase, P38, and c-Jun N-terminal kinase mRNA expression, and the upregulation of cytochrome P4502J5 and insulin receptor substrate 1/2 mRNA expression. However, GP antibiotic treatment did not induce significant alterations in FBG and AA levels or gene expression. Overall, our findings suggest that the hypoglycemic effect of GP may be intricately linked to alterations in AA metabolism, which depends on the GM.

Advances in the treatment of type 2 diabetes mellitus by natural plant polysaccharides through regulation of gut microbiota and metabolism: A review

The prevalence and impact of type 2 diabetes mellitus (T2DM) is a major global health problem. The treatment process of T2DM is long and difficult to cure. Therefore, it is necessary to explore alternative or complementary methods to deal with the various challenges brought by T2DM. Natural plant polysaccharides (NPPs) have certain potential in the treatment of T2DM. However, many studies have not considered the relationship between the structure of NPPs and their anti-T2DM activity. This paper reviews the relevant anti-T2DM mechanisms of NPPs, including modulation of insulin action, promotion of glucose metabolism and modulation of postprandial glucose levels, anti-inflammation and modulation of gut microbiota (GM) and metabolism. This paper provides an in-depth study of the conformational relationships of NPPs and facilitates the development of anti-T2DM drugs or dietary supplements with NPPs.

Enhanced hypoglycemic effects of konjac glucomannan combined with Polygonatum cyrtonema Hua polysaccharide in complete nutritional liquid diet fed type 2 diabetes mice

In our aging society, dysphagia and malnutrition are growing concerns, necessitating intervention. Liquid nutrition support offers a practical solution for traditional dietary issues, but it raises a key issue: the potential for post-meal glucose spikes impacting efficacy. This study examined the effects of supplementation of Polygonatum cyrtonema Hua polysaccharide (PCP), konjac glucomannan (KGM) and their combination on acute phase postprandial glycemic response and long-term glucose metabolism in T2DM mice on a complete nutritional liquid diet. KGM was more effective in reducing postprandial glucose response, while PCP was more prominent in ameliorating long-term glucose metabolism. The KGM-PCP combination demonstrated superior outcomes in fasting blood glucose, insulin, and glucose homeostasis. PCP and KGM also influenced the composition and abundance of the gut microbiome, with the H-PCP group showing optimal performance. Moreover, the KGM-PCP combination improved body weight, lipid homeostasis, and liver health the most. PCP potentially regulates glycemia through metabolic pathways, while KGM improves glycemic metabolism by reducing postprandial glucose levels in response to viscous intestinal contents. This research identifies the structure, viscosity properties, and hypoglycemic effects of KGM and PCP in complete nutritional liquid diet fed T2DM mice, enabling their strategic utilization as hypoglycemic components in nutritional administration and glycemic regulation.

A comparison study on polysaccharides extracted from banana flower using different methods: Physicochemical characterization, and antioxidant and antihyperglycemic activities

This work investigated and compared the physicochemical characteristics, and antioxidant and antihyperglycemic properties in vitro of polysaccharides from a single banana flower variety (BFPs) extracted by different methods. BFPs extracted using hot water (HWE), acidic (CAE), alkaline (AAE), enzymatic (EAE), ultrasonic (UAE) and hot water-alkaline (HAE) methods showed different chemical composition, monosaccharide composition, molecular weight, chain conformation and surface morphology, but similar infrared spectra characteristic, main glycosidic residues, crystalline internal and thermal stability, suggesting that six methods have diverse impacts on the degradation of BFPs without changing the main structure. Then, among six BFPs, the stronger antioxidant activity in vitro was found in BFP extracted by HAE, which was attributed to its maximum uronic acid content (21.67 %) and phenolic content (0.73 %), and moderate molecular weight (158.48 kDa). The highest arabinose and guluronic acid contents (18.59 % and 1.31 % in molar ratios, respectively) and the lowest uronic acid content (14.30 %) in BFP extracted by HWE contributed to its better α-glucosidase inhibitory activity in vitro (66.55 %). The data offered theoretical evidence for choosing suitable extraction methods to acquire BFPs with targeted biological activities for applications, in which HAE and HWE could serve as beneficial methods for preparing antioxidant BFP and antihyperglycemic BFP, respectively.

Flavonoid substituted polysaccharides from Tamarix chinensis Lour. alleviate H1N1-induced acute lung injury via inhibiting complement system

ETHNOPHARMACOLOGICAL RELEVANCE

Viral pneumonia is a highly pathogenic respiratory infectious disease associated with excessive activation of the complement system. Our previous studies found that the anticomplement polysaccharides from some medicinal plants could significantly alleviate H1N1-induced acute lung injury (H1N1-ALI). The leaves and twigs of Tamarix chinensis Lour. are traditionally used as a Chinese medicine Xiheliu for treating inflammatory disorders. Interestingly, its crude polysaccharides (MBAP90) showed potent anticomplement activity in vitro.

AIM OF THE STUDY

To evaluate the therapeutic effects and possible mechanism of MBAP90 on viral pneumonia and further isolate and characterize the key active substance of MBAP90.

MATERIALS AND METHODS

The protective effects of MBAP90 were evaluated by survival tests and pharmacodynamic experiments on H1N1-ALI mice. Histopathological changes, viral load, inflammatory markers, and complement deposition in lungs were analyzed by H&E staining, enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry (IHC), respectively. An anticomplement homogenous polysaccharide (MBAP-3) was obtained from MBAP90 by bio-guided separation, and its structure was further characterized by methylation analysis and NMR spectroscopy.

RESULTS

Oral administration of MBAP90 at a dose of 400 mg/kg significantly increased the survival rate of mice infected with the lethal H1N1 virus. In H1N1-induced ALI, mice treated with MBAP90 (200 and 400 mg/kg) could decrease the lung index, lung pathological injury, the levels of excessive proinflammatory cytokines (IL-6, TNF-α, MCP-1, IL-18, and IL-1β), and complement levels (C3c and C5b-9). In addition, MBAP-3 was characterized as a novel homogenous polysaccharide with potent in vitro anticomplement activity (CH50: 0.126 ± 0.002 mg/mL), containing 10.51% uronic acids and 9.67% flavonoids, which were similar to the composition of MBAP90. The backbone of MBAP-3 consisted of →4)-α-D-Glcp-(1→, →3,4,6)-α-D-Glcp-(1→, and →3,4)-α-D-Glcp-(1→, with branches comprising α-L-Araf-(1→, α-D-GlcpA-(1→, →4,6)-α-D-Manp-(1→ and →4)-β-D-Galp-(1 → . Particularly, O-6 of →4)-β-D-Galp-(1→ was conjugated with a flavonoid, myricetin.

CONCLUSIONS

MBAP90 could ameliorate H1N1-ALI by inhibiting inflammation and over-activation of the complement system. These polysaccharides (MBAP90 and MBAP-3) with relative high contents of uronic acid and flavonoid substituent might be vital components of T. chinensis for treating viral pneumonia.

In silico exploration of the potential inhibitory activities of in-house and ZINC database lead compounds against alpha-glucosidase using structure-based virtual screening and molecular dynamics simulation approach

Inhibitors of α-glucosidase have been used to treat type-2 diabetes (T2DM) by preventing the breakdown of carbohydrates into glucose and prevent enhancing glucose conversion. Structure-based virtual screening (SBVS) was used to generate novel chemical scaffold-ligand α-glucosidase inhibitors. The databases were screened against the receptor α-glucosidase using SBVS and molecular dynamics simulation (MDS) techniques in this study. Based on molecular docking studies, three and two compounds of α-glucosidase inhibitors were chosen from a commercial database (ZINC) and an In-house database for this study respectively. The mode of binding interactions of the selected compounds later predicted their α-glucosidase inhibitory potential. Finally, one out of three lead compound from ZINC and one out of two lead compound from In-house database were shortlisted based on interactions. Furthermore, MDS and post-MDS strategies were used to refine and validate the shortlisted leads along with the reference acarbose/α-glucosidase. The Hits' ability to inhibit α-glucosidase was predicted by SBVS, indicating that these compounds have good inhibitory activities. The lead inhibitor's structure may serve as templates for the design of novel inhibitors, and in vitro testing to confirm their anti-diabetic potential is necessary. These insights can help rationally design new effective anti-diabetic drugs.Communicated by Ramaswamy H. Sarma.

Research progress in extraction, purification, structure of fruit and vegetable polysaccharides and their interaction with anthocyanins/starch

Fruits and vegetables contain polysaccharides, polyphenols, antioxidant enzymes, and various vitamins, etc. Fruits and vegetables polysaccharides (FVPs), as an important functional factor in health food, have various biological activities such as lowering blood sugar, blood lipids, blood pressure, inhibiting tumors, and delaying aging, etc. In addition, FVPs exhibit good physicochemical properties including low toxicity, biodegradability, biocompatibility. Increasing research has confirmed that FVPs could enhance the stability and biological activities of anthocyanins, affecting their bioavailability to improve food quality. Simultaneously, the addition of FVPs in natural starch suspension could improve the physicochemical properties of natural starch such as viscosity, gelling property, water binding capacity, and lotion stability. Hence, FVPs are widely used in the modification of natural anthocyanins/starch. A systematic review of the latest research progress and future development prospects of FVPs is very necessary to better understand them. This paper systematically reviews the latest progress in the extraction, purification, structure, and analysis techniques of FVPs. Moreover, the review also introduces the potential mechanisms, evaluation methods, and applications of the interaction between polysaccharides and anthocyanins/starch. The findings can provide important references for the further in-depth development and utilization of FVPs.

A polysaccharide NAP-3 from Naematelia aurantialba: Structural characterization and adjunctive hypoglycemic activity

A novel polysaccharide (NAP-3) was isolated and purified from Naematelia aurantialba after water extraction. The structure of NAP-3, which was determined by FT-IR, HPLC, GC-MS, and NMR, indicated that NAP-3 was a homogeneous polysaccharide with the molecular weight of 428 kDa, mainly consisted of β-1, 3-D-Manp, β-1, 2, 3-D-Manp, β-D-Xylp, β-1, 4-D-Glcp, β-1, 4-D-Rhap in a molar ratio of 6.49: 1.11: 2.4: 0.13: 0.83. In vitro α-glucosidase and α-amylase inhibitory assay showed that NAP-3 had a low IC₅₀ value, which exhibited similar enzyme inhibitory activity as acarbose. NAP-3 was evaluated as an adjuvant with metformin for antidiabetic therapy in HFD/STZ-induced diabetic mice and insulin resistance HepG2 cells. The combination of NAP-3 and metformin in diabetic mice exhibited significant hypoglycemic activity, reducing body weight, serum insulin levels, glucose tolerance, insulin tolerance, and increasing antioxidant levels compared to metformin alone. The combination of NAP-3 and metformin improved oxidative stress by increasing ROS clearance, thereby enhancing glucose uptake in HepG2 cells. This study provided new data for the study of Naematelia aurantialba polysaccharides and offers a new adjuvant therapy for the treatment of diabetes.

Preparation, structural characterization, and bioactivities of polysaccharides from Psidium guajava: A review

Psidium guajava L. is one of the most pivotal members belong to the Myrtaceae family, and it is an important tropical fruit with highly nutritional, healthy, and pharmacological values prevailing in worldwide for decades. The polysaccharides of P. guajava (PGPs) are served as one of the most active constituents, which possess a variety of biofunctionalities including anti-inflammatory, antidiarrheic, antihypertension, and antidiabetic properties. Hence, a systematic review aimed to comprehensively summarize the recent research advances of PGPs is necessary for facilitating their better understanding. The present review discussed current research progress on the PGPs, including extraction and purification methods, structural features, biological activities, and potential pharmacological mechanism. In addition, this review may also provide some valuable insights for further development and potential value in affording functionally useful agents in food industry or therapeutically effective medicine in the fields of P. guajava polysaccharides.

Tremella fuciformis polysaccharide reduces obesity in high-fat diet-fed mice by modulation of gut microbiota

Obesity is a metabolic disease associated with gut microbiota and low-grade chronic inflammation. Tremella fuciformis is a medicinal and edible fungus; polysaccharide (TP) is the main active component, which has a variety of biological activities, such as hypoglycemic and hypolipidemic. However, the anti-obesity effects and potential mechanisms of TP have never been reported. This study was conducted to elucidate the inhibitory effect of TP on high-fat diet (HFD)-induced obesity in mice. Mice were split into five groups: normal chow diet (NCD) group, NCD_TP_H group, HFD group, HFD_TP_L group and HFD_TP_H group. Our study showed that TP inhibited high-fat diet-induced weight gain and fat accumulation in mice and reduced blood glucose, hyperlipidemia and inflammation. TP also improved gut microbiota disorders by reducing the Firmicutes/Bacteroidetes ratio and modulating the relative abundance of specific gut microbiota. We also found that the anti-obesity and gut microbiota-modulating effects of TP could be transferred to HFD-fed mice via faecal microbiota transplantation (FMT), confirming that the gut microbiota was one of the targets of TP for obesity inhibition. Further studies showed that TP increased the production of short-chain fatty acids and the secretion of intestinal hormones. Our studies showed that TP inhibited obesity by modulating inflammation and the microbe-gut-brain axis, providing a rationale for developing TP to treat obesity and its complications.

Psidium guajava L. An Incalculable but Underexplored Food Crop: Its Phytochemistry, Ethnopharmacology, and Industrial Applications

Psidium guajava L. (guava) is a small tree known for its fruit flavor that is cultivated almost around the globe in tropical areas. Its fruit is amazingly rich in antioxidants, vitamin C, potassium, and dietary fiber. In different parts of the world, this plant holds a special place with respect to fruit and nutritional items. Pharmacological research has shown that this plant has more potential than just a fruit source; it also has beneficial effects against a variety of chronic diseases due to its rich nutritional and phytochemical profile. The primary goal of this document is to provide an updated overview of Psidium guajava L. and its bioactive secondary metabolites, as well as their availability for further study, with a focus on the health benefits and potential industrial applications. There have been several studies conducted on Psidium guajava L. in relation to its use in the pharmaceutical industry. However, its clinical efficacy and applications are still debatable. Therefore, in this review a detailed study with respect to phytochemistry of the plant through modern instruments such as GC and LC-MS has been discussed. The biological activities of secondary metabolites isolated from this plant have been extensively discussed. In order to perform long-term clinical trials to learn more about their effectiveness as drugs and applications for various health benefits, a structure activity relationship has been established. Based on the literature, it is concluded that this plant has a wide variety of biopharmaceutical applications. As a whole, this article calls for long-term clinical trials to obtain a greater understanding of how it can be used to treat different diseases.

Recent Updates on Phytoconstituent Alpha-Glucosidase Inhibitors: An Approach towards the Treatment of Type Two Diabetes

Diabetes is a common metabolic disorder marked by unusually high plasma glucose levels, which can lead to serious consequences such as retinopathy, diabetic neuropathy and cardiovascular disease. One of the most efficient ways to reduce postprandial hyperglycemia (PPHG) in diabetes mellitus, especially insulin-independent diabetes mellitus, is to lower the amount of glucose that is absorbed by inhibiting carbohydrate hydrolyzing enzymes in the digestive system, such as α-glucosidase and α-amylase. α-Glucosidase is a crucial enzyme that catalyzes the final stage of carbohydrate digestion. As a result, α-glucosidase inhibitors can slow D-glucose release from complex carbohydrates and delay glucose absorption, resulting in lower postprandial plasma glucose levels and control of PPHG. Many attempts have been made in recent years to uncover efficient α-glucosidase inhibitors from natural sources to build a physiologic functional diet or lead compound for diabetes treatment. Many phytoconstituent α-glucosidase inhibitors have been identified from plants, including alkaloids, flavonoids, anthocyanins, terpenoids, phenolic compounds, glycosides and others. The current review focuses on the most recent updates on different traditional/medicinal plant extracts and isolated compounds' biological activity that can help in the development of potent therapeutic medications with greater efficacy and safety for the treatment of type 2 diabetes or to avoid PPHG. For this purpose, we provide a summary of the latest scientific literature findings on plant extracts as well as plant-derived bioactive compounds as potential α-glucosidase inhibitors with hypoglycemic effects. Moreover, the review elucidates structural insights of the key drug target, α-glucosidase enzymes, and its interaction with different inhibitors.

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 features and antioxidant activities of polysaccharides from different parts of Codonopsis pilosula var. modesta (Nannf.) L. T. Shen

In this study, three acidic polysaccharides from different plant parts of Codonopsis pilosula var. Modesta (Nannf.) L. T. Shen were obtained by ion exchange chromatography and gel filtration chromatography, and the yields of these three polysaccharides were different. According to the preliminary experimental results, the antioxidant activities of the polysaccharides from rhizomes and fibrous roots (CLFP-1) were poor, and was thus not studied further. Due to this the structural features of polysaccharides from roots (CLRP-1) and aerial parts (CLSP-1) were the object for this study and were structurally characterized, and their antioxidant activities were evaluated. As revealed by the results, the molecular weight of CLRP-1and CLSP-1 were 15.9 kDa and 26.4 kDa, respectively. The monosaccharide composition of CLRP-1 was Ara, Rha, Fuc, Xyl, Man, Gal, GlcA, GalA in a ratio of 3.8: 8.4: 1.0: 0.8: 2.4: 7.4: 7.5: 2.0: 66.7, and Ara, Rha, Gal, GalA in a ratio of 5.8: 8.9: 8.0: 77.0 in for CLSP-1. The results of structural elucidation indicated that both CLRP-1 and CLSP-1 were pectic polysaccharides, mainly composed of 1, 4-linked galacturonic acid with long homogalacturonan regions. Arabinogalactan type I and arabinogalactan type II were presented as side chains. The antioxidant assay in IPEC-J2 cells showed that both CLRP-1 and CLSP-1 promoted cell viability and antioxidant activity, which significantly increase the level of total antioxidant capacity and the activity of superoxide dismutase, catalase, and decrease the content of malondialdehyde. Moreover, CLRP-1 and CLSP-1 also showed powerful antioxidant abilities in Caenorhabditis elegans and might regulate the nuclear localization of DAF-16 transcription factor, induced antioxidant enzymes activities, and further reduced reactive oxygen species and malondialdehyde contents to increase the antioxidant ability of Caenorhabditis elegans. Thus, these finding suggest that CLRP-1 and CLSP-1 could be used as potential antioxidants.

An Acidic Polysaccharide with Anti-Inflammatory Effects from Blackened Jujube: Conformation and Rheological Properties

An acidic polysaccharide fraction (BJP-4) was isolated from blackened jujube, and its advanced structures and anti-inflammatory activity were investigated. X-ray diffraction showed that BJP-4 exhibits both crystalline and amorphous portions. Atomic force microscopy data suggested that it contains a large number of spherical lumps. Circular dichroism and Congo red experiments revealed that it has no triple-helix conformation. In steady shear flow results, the BJP-4 solution was a pseudoplastic non-Newtonian fluid with acid-base stability. BJP-4 (20 mg/mL) showed liquid-like properties (G″ > G′), while it performed weak gel-like behavior at a high concentration (40 mg/mL) (G′ > G″). The anti-inflammatory effects of BJP-4 were further evaluated through in vitro experiments. BJP-4 could down-regulate the over-secretion of inflammatory factors (NO, IL-6, IL-1β, TNF-α, iNOS and COX-2) in RAW264.7 cells due to LPS stimulation. Moreover, it demonstrated that BJP-4 restrained the NF-κB signal pathway by regulating TLR4 expression, reducing IκBα phosphorylation level and NF-κB p65 nuclear translocation. In summary, this present study contributes to the application of blackened jujube polysaccharides in the foods and medicine field.

The crude guava polysaccharides ameliorate high-fat diet-induced obesity in mice via reshaping gut microbiota

Guava is a popular fruit consumed worldwide with beneficial effects in regulation of glucose and lipid metabolism. Although polysaccharides are a major phytochemical component of guava, to date, the alleviative effects of polysaccharides from the guava fruit against diet-induced obesity remain unclear. The relationship between the anti-obesity effects of guava polysaccharide (GP) and gut microbiota is unknown. In current study, seven-week-old C57BL/6 mice were fed high-fat diet (HFD) supplemented with GP (100 mg/kg) by oral gavage for 11 weeks. GP supplementation alleviated HFD-induced body weight gain and visceral obesity, and reduced serum cholesterol, triglyceride, and LDL-C levels. In addition, GP ameliorated insulin resistance and prevented hepatic lipid accumulation and meta-inflammation in both liver and adipose tissues in obese mice. Remarkably, GP treatment restored the Firmicutes/Bacteroidetes ratio, induced growth of beneficial bacteria including Clostridium XlVa, Parvibacter, and Enterorhabdus, and decreased in inflammation-related bacteria Mucispirillum in mice fecal samples, accompanied with enhanced production of colonic short chain fatty acids especially butyric acid. However, the metabolic benefits of GP diminished in antibiotics-treated HFD-fed mice. Overall, GP improved metabolic profiles in HFD-induced obese mice via the mediation of gut microbiota-dependent pathways. GP might be developed and utilized as prebiotics in nutraceutical and food industry.

Two Natural Flavonoid Substituted Polysaccharides from Tamarix chinensis: Structural Characterization and Anticomplement Activities

Two novel natural flavonoid substituted polysaccharides (MBAP-1 and MBAP-2) were obtained from Tamarix chinensis Lour. and characterized by HPGPC, methylation, ultra-high-performance liquid chromatography-ion trap tandem mass spectrometry (UPLC-IT-MSⁿ), and NMR analysis. The results showed that MBAP-1 was a homogenous heteropolysaccharide with a backbone of 4)-β-d-Glcp-(1→ and →3,4,6)-β-d-Glcp-(1→. MBAP-2 was also a homogenous polysaccharide which possessed a backbone of →3)-α-d-Glcp-(1→, →4)-β-d-Glcp-(1→ and →3,4)-β-d-Glcp-2-OMe-(1→. Both the two polysaccharides were substituted by quercetin and exhibited anticomplement activities in vitro. However, MBAP-1 (CH₅₀: 0.075 ± 0.004 mg/mL) was more potent than MBAP-2 (CH₅₀: 0.249 ± 0.006 mg/mL) and its reduced product, MBAP-1R (CH₅₀: 0.207 ± 0.008 mg/mL), indicating that multiple monosaccharides and uronic acids might contribute to the anticomplement activity of the flavonoid substituted polysaccharides of T. chinensis. Furthermore, the antioxidant activity of MBAP-1 was also more potent than that of MBAP-2. In conclusion, these two flavonoid substituted polysaccharides from T. chinensis were found to be potential oxidant and complement inhibitors.

Structural characterization and anti-tumor activity in vitro of a water-soluble polysaccharide from dark brick tea

Recently, more and more attention has been paid to the structure and application of tea polysaccharides. Herein, a water-soluble homogeneous polysaccharide (DTP-1) from dark brick tea was purified, characterized, and investigated its anti-tumor activity in vitro. The DTP-1 with a molecular weight of 11,805 Da is mainly composed of glucose, galactose and arabinose. It has a backbone, which is composed of →4)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, →6)-β-D-Galp-(1→, →2)-α-L-Araf-(1→, →3)-β-D-Galp-(1→, with →4,6)-β-D-Galp-(1 → as branching point and →1)-β-D-Glcp as terminal. In addition, DTP-1 could significantly affect the viability of A549 and SMMC7721 cells with an inhibition rate of 31.71% and 33.38% (600 μg/mL, 24 h), respectively, by inducing apoptosis and inhibiting cell migration. Moreover, DTP-1 had no effect on corresponding normal cells. Therefore, DTP-1 showed great potential to become a functional food and an anti-tumor drug.

Comparative study on the structural characterization and α-glucosidase inhibitory activity of polysaccharide fractions extracted from Sargassum fusiforme at different pH conditions

Sargassum fusiforme polysaccharides (SFPs), including SFP-3-40, SFP-3-60, SFP-3-80, SFP-7-40, SFP-7-60, SFP-7-80, SFP-10-40, SFP-10-60, and SFP-10-80, were extracted at different pH (3, 7, and 10), and then precipitated with graded precipitation of 40%, 60% and 80% (v/v) ethanol solution, respectively. Their physicochemical properties and α-glucosidase inhibitory activity were determined. Results showed that SFPs significantly differed in the contents of total sugar, protein, uronic acid, sulfate, the zeta potential, and molecular weight distribution. SFPs, including SFP-10-40, SFP-10-60, and SFP-10-80, had bigger absolute zeta potential value and higher respective average molecular weight in the same ethanol concentration precipitate. All samples were mainly composed of fucose, glucuronic acid, and mannose with different molar ratios. The extraction pH and precipitation ethanol solution concentration caused little changes in functional groups, but significantly altered surface morphology of SFPs. Congo red test revealed that all polysaccharides were not helical polysaccharides. Rheological measurements indicated that SFPs were pseudoplastic fluids and showed elastic behavior of the gel. Except SFP-3-40 and SFP-3-60, all other samples had a stronger α-glucosidase inhibitory activity than that of acarbose. The inhibition type of SFPs against α-glucosidase varied owing to different extraction pH and precipitation ethyl concentration. This study shows that extraction pH can significantly affect the structure and hypoglycemic activity of SFPs and provide a data support for the scientific use of Sargassum fusiforme in industrial production.

Novel Antioxidant and Hypoglycemic Water-Soluble Polysaccharides from Jasmine Tea

There have been few studies dealing with chemical elucidation and pharmacological potentials of water-soluble polysaccharides from jasmine tea, limiting their use in functional foods. In this study, water-soluble polysaccharides (named as JSP) were extracted from Jasminum sambac (L.) Aiton tea and fractionated to afford two sub-fractions (JSP-1 and JSP-2). The main structural characteristics of novel JSP sub-fractions were determined by high performance gel permeation chromatography, ultra-performance liquid chromatography-tandem mass spectrometry, Fourier transform infrared, and nuclear magnetic resonance analysis. Physiologically, the abilities of JSP-1 and JSP-2 to reduce ferric ions, scavenge DPPH and hydroxyl radicals, as well as protect islet cells were confirmed in vitro. JSP-1 exhibited better antioxidant and hypoglycemic activities than JSP-2. The molecular weights of JSP-1 and JSP-2 were 18.4 kDa and 14.1 kDa, respectively. JSP-1 was made up of glucose, galactose, rhamnose, xylose, arabinose, and galacturonic acid with molar ratios 1.14:4.69:1.00:9.92:13.79:4.09, whereas JSP-2 with a triple helical structure was composed of galactose, rhamnose, xylose, arabinose, and galacturonic acid as 3.80:1.00:8.27:11.85:5.05 of molar ratios. JSP-1 contains →1)-α-Galƒ-(3→, →1)-α-Galƒ-(2→, →1)-α-Araƒ-(5→, →1)-α-Araƒ-(3→, →1)-α-Araƒ-(3,5→, →1)-β-Xylp-(2→ and →1)-β-Xylp-(3→ residues in the backbone. These results open up new pharmacological prospects for the water-soluble polysaccharides extracted from jasmine tea.

Plant/algal polysaccharides extracted by microwave: A review on hypoglycemic, hypolipidemic, prebiotic, and immune-stimulatory effect

Microwave-assisted extraction (MAE) is an emerging technology to obtain polysaccharides with an extensive spectrum of biological characteristics. In this study, the hypoglycemic, hypolipidemic, prebiotic, and immunomodulatory (e.g., antiinflammatory, anticoagulant, and phagocytic) effects of algal- and plant-derived polysaccharides rich in glucose, galactose, and mannose using MAE were comprehensively discussed. The in vitro and in vivo results showed that these bioactive macromolecules with the low digestibility rate could effectively alleviate the fatty acid-induced lipotoxicity, acute hemolysis, and dyslipidemia status. The optimally extracted glucomannan- and glucogalactan-containing polysaccharides revealed significant antidiabetic effects through inhibiting α-amylase and α-glucosidase, improving dynamic insulin sensitivity and secretion, and promoting pancreatic β-cell proliferation. These bioactive macromolecules as prebiotics not only improve the digestibility in gastrointestinal tract but also reduce the survival rate of pathogens and tumor cells by activating macrophages and producing pro-inflammatory biomarkers and cytokines. They can effectively prevent gastrointestinal disorders and microbial infections without any toxicity.

Inhibitory Activity and Mechanism Investigation of Hypericin as a Novel α-Glucosidase Inhibitor

α-glucosidase is a major enzyme that is involved in starch digestion and type 2 diabetes mellitus. In this study, the inhibition of hypericin by α-glucosidase and its mechanism were firstly investigated using enzyme kinetics analysis, real-time interaction analysis between hypericin and α-glucosidase by surface plasmon resonance (SPR), and molecular docking simulation. The results showed that hypericin was a high potential reversible and competitive α-glucosidase inhibitor, with a maximum half inhibitory concentration (IC₅₀) of 4.66 ± 0.27 mg/L. The binding affinities of hypericin with α-glucosidase were assessed using an SPR detection system, which indicated that these were strong and fast, with balances dissociation constant (KD) values of 6.56 × 10⁻⁵ M and exhibited a slow dissociation reaction. Analysis by molecular docking further revealed that hydrophobic forces are generated by interactions between hypericin and amino acid residues Arg-315 and Tyr-316. In addition, hydrogen bonding occurred between hypericin and α-glucosidase amino acid residues Lys-156, Ser-157, Gly-160, Ser-240, His-280, Asp-242, and Asp-307. The structure and micro-environment of α-glucosidase enzymes were altered, which led to a decrease in α-glucosidase activity. This research identified that hypericin, an anthracene ketone compound, could be a novel α-glucosidase inhibitor and further applied to the development of potential anti-diabetic drugs.

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.

An overview on the role of bioactive α-glucosidase inhibitors in ameliorating diabetic complications

Recently the use of bioactive α-glucosidase inhibitors for the treatment of diabetes have been proven to be the most efficient remedy for controlling postprandial hyperglycemia and its detrimental physiological complications, especially in type 2 diabetes. The carbohydrate hydrolysing enzyme, α-glucosidase, is generally competitively inhibited by the α-glucosidase inhibitors and results in the delayed glucose absorption in small intestine, ultimately controlling the postprandial hyperglycemia. Here we have reviewed the most recent updates in the bioactive α-glucosidase inhibitors category. This review provides an overview of the α-glucosidase inhibitory potentials and efficiency of controlling postprandial hyperglycemia of various bioactive compounds such as flavonoids, phenolic compound, polysaccharide, betulinic acid, tannins, anthocyanins, steroids, polyol, polyphenols, galangin, procyanidins, hydroxyl-α-sanshool, hydroxyl-β-sanshool, erythritol, ganomycin, caffeoylquinic acid, resin glycosides, saponins, avicularin, oleanolic acids, urasolic acid, ethanolic extracts etc., from various dietary and non-dietary naturally occurring sources.

Screening active fractions from Pinus massoniana pollen for inhibiting ALV-J replication and their structure activity relationship investigation

The objective was to identify the active fractions of polysaccharide against replication of ALV-J and elucidate their structure activity relationship. The optimal extraction conditions were extracting temperature 90℃, pH 9 and the ratio of liquid to solid 30:1. Under these conditions, extraction yield of total polysaccharide was 6.5 % ± 0.19 %. Total polysaccharide was then purified by DEAE-52 cellulose and Sephadex G-200 gel. Three fractions, PPP-1, PPP-2, and PPP-3, were identified with molecular weight of 463.70, 99.41, and 26.97 kDa, respectively. Three polysaccharide fractions were all composed of 10 monosaccharides in different proportions. Compared with PPP-1, which was mainly composed of glucose, PPP-2 and PPP-3 contained a higher proportion of galactose, glucuronic acid and galacturonic acid. The Congo red assay indicated that the PPP-2 may have a triple helical structure, while PPP-1 and PPP-3 were absent. In vitro assay showed that there was no significant cytotoxicity among the polysaccharide fractions under the concentration of 800 μg mL^-1 (P > 0.05). The antiviral test showed that PPP-2 had the strongest activity, indicating PPP-2 was the major antiviral component. The structure-activity relationship showed that the antiviral activities of polysaccharide fractions were affected by their monosaccharide composition, molecular weight, and triple helical structure, which was a result of a combination of multiple molecular structural factors. These results showed that the PPP-2 could be exploited as a valued product for replacing synthetic antiviral drugs, and provided support for future applications of polysaccharide from Pinus massoniana pollen as a useful source for antiviral agent.

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.

Evaluation of the antidiabetic potential of Psidium guajava L. (Myrtaceae) using assays for α-glucosidase, α-amylase, muscle glucose uptake, liver glucose production, and triglyceride accumulation in adipocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Psidium guajava L. (Myrtaceae) leaves are used as an herbal antidiabetic remedy in several parts of the world. On Madagascar, both the bark and leaves are used for treatment of diabetes.

MATERIALS AND METHODS

Dilution series of ethanolic extracts of P. guajava leaves and bark were used for determining inhibitory activities against yeast α-glucosidase and porcine α-amylase. Skeletal muscle glucose uptake was measured using 2-deoxy-D-(1-³H)-glucose in murine C2C12 skeletal muscle cells. Hepatic glucose-6-phosphatase activity in rat hepatoma H4IIE cells and triglyceride accumulation in murine 3T3-L1 adipocyte-like cells were assessed using Wako AutoKit Glucose assays and AdipoRed reagent, respectively. Cells were incubated for 18 h with the maximal non-toxic concentrations of the plant extracts determined by the lactate dehydrogenase cytotoxicity assay.

RESULTS

Ethanolic extracts of P. guajava leaf and bark inhibited α-glucosidase with IC₅₀ values of 1.0 ± 0.3 and 0.5 ± 0.01 μg/mL, respectively. In the α-amylase inhibition assay, the ethanolic extract of bark of P. guajava showed an IC₅₀ value of 10.6 ± 0.4 μg/mL. None of the extracts were able to reduce glucose-6-phosphatase activity in rat hepatoma H4IIE cells. In contrast, P. guajava leaf extract significantly increased 2-deoxy-D-[1-³H]-glucose uptake in C2C12 muscle cells (161.4 ± 10.1%, p = 0.0015) in comparison to the dimethyl sulfoxide (DMSO) vehicle control, as did the reference compounds metformin (144.0 ± 7.7%, p = 0.0345) and insulin (141.5 ± 13.8%, p = 0.0495). Furthermore, P. guajava leaf and bark extracts, as well as the reference compound rosiglitazone, significantly enhanced triglyceride accumulation in 3T3-L1 cells (252.6 ± 14.2%, p < 0.0001, 211.1 ± 12.7%, p < 0.0001, and 201.1 ± 9.2%, p < 0.0001, respectively) to levels higher than the DMSO vehicle control. Moreover, P. guajava leaf extract significantly enhanced the triglyceride accumulation in 3T3-L1 cells compared to rosiglitazone.

CONCLUSION

The results demonstrated that P. guajava leaf and bark extracts can be used as a natural source of α-glucosidase inhibitors. In addition, the bark extract of P. guajava was an effective α-amylase inhibitor. Moreover, P. guajava leaf extract improved glucose uptake in muscle cells, while both leaf and bark extracts enhanced the triglyceride content in adipocytes in culture. P. guajava leaf and bark extracts may thus hypothetically have future applications in the treatment of type 2 diabetes.

Structural features of pectic polysaccharides from stems of two species of Radix Codonopsis and their antioxidant activities

In this study, two pectic polysaccharides from stems of Codonopsis pilosula (CPSP-1) and C. tangshen (CTSP-1) were obtained by ion exchange chromatography and gel filtration. The molecular weight of CPSP-1 and CTSP-1 were 13.1 and 23.0 kDa, respectively. The results of structure elucidation indicated that both CPSP-1 and CTSP-1 are pectic polysaccharides with long homogalacturonan regions (HG) (some of galacturonic acid units were methyl esterified) and rhamnogalacturonan I (RG-I) regions. Side chains for CTSP-1 are both arabinogalactan type I (AG-I) and type II (AG-II), while CPSP-1 only has AG-II. The biological test demonstrated that CPSP-1 and CTSP-1 displayed an antioxidant property through mediating the intestinal cellular antioxidant defense system, which could protect cultured intestinal cells from oxidative stress induced oxidative damages and cell viability suppression. CPSP-1 and CTSP-I showed different bioactivities and mechanisms, which may be due to the difference in their structures.

Trends in the extraction, purification, characterisation and biological activities of polysaccharides from tropical and sub-tropical fruits - A comprehensive review

Tropical and sub-tropical fruits are tremendous sources of polysaccharides (PSs), which are of great interest in the human welfare system as natural medicines, food and cosmetics. This review paper aims to highlight the recent trends in extraction (conventional and non-conventional), purification and analytic techniques of fruit polysaccharides (FPSs). The chemical structure and biological activities, such as immunomodulatory, anti-cancer, anti-oxidant, anti-inflammatory, anti-viral, anti-coagulant and anti-diabetic effects, of PSs extracted from 53 various fruits were compared and discussed. With this wide coverage, a total of 172 scientific articles were reviewed and discussed. This comprehensive survey from previous studies suggests that the FPSs are non-toxic and highly biocompatible. In addition, this review highlights that FPSs might be excellent functional foods as well as effective therapeutic drugs. Finally, the future research advances of FPSs are also described. The content of this review will promote human wellness-based food product development in the future.

Structural Features of Three Hetero-Galacturonans from Passiflora foetida Fruits and Their in Vitro Immunomodulatory Effects

Passiflora foetida is a horticultural plant and vital traditional Chinese herbal medicine. In our previous study, the characterization and immuno-enhancing effect of fruits polysaccharide 1 (PFP1), a water-eluted hetero-mannan from wild Passiflora foetida fruits, were investigated. Herein, another three salt-eluted novel polysaccharides, namely PFP2, PFP3, and PFP4, were obtained and structurally characterized. The results showed that PFP2, PFP3, and PFP4 were three structurally similar hetero-galacturonans with different molecular weights of 6.11 × 104, 4.37 × 104, and 3.48 × 105 g/mol, respectively. All three of these hetero-galacturonans are mainly composed of galacturonic acid, galactose, arabinose (75.69%, 80.39%, and 74.30%, respectively), and other monosaccharides including mannose, fucose, glucose, ribose, xylose, and glucuronic acid (24.31%, 19.61, and 25.70%, respectively), although differences in their backbone structure exist. Additionally, immunomodulatory assay indicated that the three hetero-galacturonans possess the ability to promote the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in RAW264.7 macrophages in a concentration-dependent manner (p < 0.05). Especially, PFP3 displayed a stronger enhancing effect than PFP2 and PFP4 at the minimum effective concentration. Therefore, the results suggested that the obtained three salt-eluted hetero-galacturonans, especially PFP3, could be utilized as immunomodulatory effectivity ingredients in nutritional/pharmaceutical industries.

Structural characterization and osteogenic bioactivities of a novel Humulus lupulus polysaccharide

Humulus lupulus is a perennial climbing plant of the subfamily Cannabioideae native to the Northern Hemisphere. The primary use of H. lupulus is in the brewing industry, where it is an essential ingredient for imparting a unique flavor (bitterness and aroma) to beer. The female flowers of H. lupulus are also used in traditional Chinese medicine, but the biologically active ingredients underlying its benefits remain unclear. China is the largest producer and consumer of H. lupulus in Asia. Using the waste from the beer-brewing process of H. lupulus as raw materials, the biologically active polysaccharides can be screened. This is useful for the full utilization of H. lupulus, potentially leading to disease prevention and treatment. In this study, we isolated a homogeneous polysaccharide (HLP50-1) with a molecular weight of 49.13 kDa from female flowers of H. lupulus via a DEAE-Cellulose 52 anion exchange column and a Sephadex G-75 gel filtration column. Methylation, GC-MS, and NMR analyses revealed that the HLP50-1 comprised →4)-α-d-Glcp-(1→, →6)-α-d-Manp-(1→, →3)-α-l-Rhap-(1→, β-d-Glcp-(1→, α-l-Araf-(1→, →4,6)-2-OAc-β-d-Galp-(1→, β-d-Galp-(1→, →3,6)-β-d-Glcp-(1→, →2,3,4)-α-d-Xylp-(1→, →6)-α-d-Glcp-(1→, →3)-α-d-Galp-(1→, →4)-α-d-Galp-(1→. Advanced structural analysis showed that the HLP50-1 contained irregular fragments of different sizes and shapes with a smooth surface. The aggregates appeared be composed of accumulated crystals. Furthermore, the osteogenic activities of the HLP50-1 were evaluated via MC3T3-E1 cells in vitro. The results showed that 0.13 μM HLP50-1 led to outstanding proliferation, differentiation, and mineralization of the MC3T3-E1 cells. Therefore, HLP50-1 has osteogenic effects, and it may be a candidate for the treatment of osteoporosis. It has broad application prospects in functional foods, health-care products, and pharmaceuticals.

Emerging strategies for the activity assay and inhibitor screening of alpha-glucosidase

The high incidence of diabetes mellitus has caused widespread concern around the world, and has quickly become one of the most prevalent and costly chronic diseases.

Structural elucidation and bioactivities of a novel arabinogalactan from Coreopsis tinctoria

Coreopsis tinctoria is being widely cultivated in Xinjiang of China, whose consumption is known to prevent diabetes and neurodegenerative diseases. To elucidate the bioactive ingredients responsible for these benefits, the alkaline soluble crude polysaccharide (CTB) was isolated from C. tinctoria. In vitro experiments showed that the inhibition of α-amylase and α-glucosidase by CTB was 13407-fold and 906-fold higher than that by positive control, respectively. Then, a novel arabinogalactan, CTBP-1, was isolated and purified from CTB. Structural analysis showed that CTBP-1 possessed a 1,6-linked β-d-Galp and 1,5-linked α-l-Araf backbone with branches substituted at the C-3 position of the 1,6-linked β-d-Galp, and the side chains included 1,5-linked α-l-Araf, T-linked β-d-Galp and T-linked α-l-Araf. The inhibitory effects of CTBP-1 on α-amylase and α-glucosidase were 2.7 and 17.9 times that of acarbose, respectively. CTBP-1 could avoid indigestion and similar side effects. In addition, CTBP-1 remarkably inhibited the release of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. In summary, CTBP-1 is a novel arabinogalactan with great potential as a treatment for type 2 diabetes and Alzheimer's disease.