Inhibition of α-glucosidase by polysaccharides from the fruit hull of Camellia oleifera Abel

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.

Structural characterization and mechanisms of macrophage immunomodulatory activity of a novel polysaccharide with a galactose backbone from the processed Polygonati Rhizoma

A purified polysaccharide with a galactose backbone (SPR-1, Mw 3,622 Da) was isolated from processed Polygonati Rhizoma with black beans (PRWB) and characterized its chemical properties. The backbone of SPR-1 consisted of [(4)-β-D-Galp-(1]9 → 4,6)-β-D-Galp-(1 → 4)-α-D-GalpA-(1 → 4)-α-D-GalpA-(1 → 4)-α-D-Glcp-(1 → 4,6)-α-D-Glcp-(1 → 4)-α/β-D-Glcp, with a branch chain of R1: β-D-Galp-(1 → 3)-β-D-Galp-(1→ connected to the →4,6)-β-D-Galp-(1→ via O-6, and a branch chain of R2: α-D-Glcp-(1 → 6)-α-D-Glcp-(1→ connected to the →4,6)-α-D-Glcp-(1→ via O-6. Immunomodulatory assays showed that the SPR-1 significantly activated macrophages, and increased secretion of NO and cytokines (i.e., IL-1β and TNF-α), as well as promoted the phagocytic activities of cells. Furthermore, isothermal titration calorimetry (ITC) analysis and molecular docking results indicated high-affinity binding between SPR-1 and MD2 with the equilibrium dissociation constant (K D) of 18.8 μM. It was suggested that SPR-1 activated the immune response through Toll-like receptor 4 (TLR4) signaling and downstream responses. Our research demonstrated that the SPR-1 has a promising candidate from PRWB for the TLR4 agonist to induce immune response, and also provided an easily accessible way that can be used for PR deep processing.

Epiphytic and endophytic bacteria on Camellia oleifera phyllosphere: exploring region and cultivar effect

The epiphytic and endophytic bacteria play an important role in the healthy growth of plants. Both plant species and growth environmental influence the bacterial population diversity, yet it is inconclusive whether it is the former or the latter that has a greater impact. To explore the communities of the epiphytic and endophytic microbes in Camellia oleifera, this study assessed three representative C. oleifera cultivars from three areas in Hunan, China by Illumina high-throughput sequencing. The results showed that the diversity and species richness of endophytic microbial community in leaves were significantly higher than those of microbial community in the epiphytic. The diversity and species richness of epiphytic and endophytic microbes are complex when the same cultivar was grown in different areas. The C. oleifera cultivars grown in Youxian had the highest diversity of epiphytic microbial community, but the lowest abundance, while the cultivars grown in Changsha had the highest diversity and species richness of endophytic microbes in leaves. It was concluded that the dominant phylum mainly included Proteobacteria, Actinobacteriota and Firmicutes through the analysis of the epiphytic and endophytic microbial communities of C. oleifera. The species and relative abundances of epiphytic and endophytic microbial community were extremely different at the genus level. The analysis of NMDS map and PERMANOVA shows that the species richness and diversity of microbial communities in epiphytes are greatly influenced by region. However, the community structure of endophytic microorganisms in leaves is influenced by region and cultivated varieties, but the influence of cultivars is more significant. Molecular ecological network analysis showed that the symbiotic interaction of epiphytic microbial community was more complex.

Effects of Steaming on Sweet Potato Soluble Dietary Fiber: Content, Structure, and Lactobacillus Proliferation In Vitro

The influence of steaming treatment on the soluble dietary fiber (SDF) of sweet potato was investigated. The SDF content increased from 2.21 to 4.04 g/100 g (in dry basis) during 20 min of steaming. The microcosmic morphology of the fractured cell wall indicated the release of SDF components during steaming. The SDF from fresh (SDF-F) and 20 min steamed (SDF-S) sweet potato was characterized. The neutral carbohydrates and uronic acid levels in SDF-S were significantly higher than SDF-F (59.31% versus 46.83%, and 25.36% versus 9.60%, respectively) (p < 0.05). The molecular weight of SDF-S was smaller than SDF-F (5.32 kDa versus 28.79 kDa). The probiotic property was evaluated by four Lactobacillus spp. fermentation in vitro with these SDF as carbon source, using inulin as the references. SDF-F showed the best proliferation effects on the four Lactobacillus spp. in terms of the OD₆₀₀ and pH in cultures, and the highest production of propanoic acid and butyric acid after 24 h fermentation. SDF-S presented higher Lactobacillus proliferation effects, but slight lower propanoic acid and butyric acid production than inulin. It was concluded that 20 min of steaming released SDF with inferior probiotic properties, which might derive from the degraded pectin, cell wall components, and resistant dextrin.

Anti-lung Cancer, Anti-microbial, Anti-α-glucosidase, Anti-sorbitol Dehydrogenase, and in silico Studies of Wogonoside and Isoliquiritigenin as Natural Compounds

Natural substances have long been used in cancer treatment, particularly in Chinese or Indian traditional medicine. Natural compounds are defined as chemical molecules that are found in fungus, marine animals, plants, or bacteria and have significant biological and pharmacological effects. Wogonoside and isoliquiritigenin are two well-known examples of plant-derived chemicals. Several modern anti-cancer medications also come from natural sources. The mic test was used to conduct tests on various natural substances' antimicrobial and antifungal properties. MTT assay was used on lung cancer, and normal (HUVEC) cell lines for analyzing of cytotoxicity and anti-lung cancer effects of Wogonoside and Isoliquiritigenin. These Wogonoside and Isoliquiritigenin had high cell death and anti-lung cancer effects against SPC-A-1, SK-LU-1, and 95D cell lines. Among the above cell lines, the best result of anti-cancer properties of Wogonoside and Isoliquiritigenin was gained in the cell line of KATO III. We examined the inhibition effects on two important enzymes using these two compounds and determined the results. PnPG and NADPH were used as substrates for enzymes. IC50 of Wogonoside and Isoliquiritigenin compounds were 18.25±4.18 and 112.64±16.02 nM for α-glucosidase and 54.72±8.61 and 47.12±11.56 nM for sorbitol dehydrogenase, respectively. For Wogonoside, gram-negative bacteria (K. pneumoniae and E. coli) had MIC values of 9.75±0.95 and 13.77±1.43 µg/mL, gram-positive bacteria (E. faecalis and S. aureus) of 37.02±4.52 and 24.85±3.64 µg/mL, respectively. Finally, molecular docking was done for enzyme results and anticancer results. Results of enzymes and antibacterial, antifungal were in level of micromolar that is good impacts. These natural compounds may be anti-diabetic, anticancer, antibacterial candidates for drug design.

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.

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.

Applications of Chinese Camellia oleifera and its By-Products: A Review

Camellia oleifera is a woody oil tree species unique to China that has been cultivated and used in China for more than 2,300 years. Most biological research on C. oleifera in recent years has focused on the development of new varieties and breeding. Novel genomic information has been generated for C. oleifera, including a high-quality reference genome at the chromosome level. Camellia seeds are used to process high-quality edible oil; they are also often used in medicine, health foods, and daily chemical products and have shown promise for the treatment and prevention of diseases. C. oleifera by-products, such as camellia seed cake, saponin, and fruit shell are widely used in the daily chemical, dyeing, papermaking, chemical fibre, textile, and pesticide industries. C. oleifera shell can also be used to prepare activated carbon electrodes, which have high electrochemical performance when used as the negative electrode of lithium-ion batteries. C. oleifera is an economically valuable plant with diverse uses, and accelerating the utilization of its by-products will greatly enhance its industrial value.

A Novel Selenium Polysaccharide Alleviates the Manganese (Mn)-Induced Toxicity in Hep G2 Cells and Caenorhabditis elegans

Manganese (Mn) is now known to have a variety of toxicities, particularly when exposed to it in the workplace. However, there are still ineffective methods for reducing Mn's hazardous effects. In this study, a new selenium polysaccharide (Se-PCS) was developed from the shell of Camellia oleifera to reduce Mn toxicity in vitro and in vivo. The results revealed that Se-PCS may boost cell survival in Hep G2 cells exposed to Mn and activate antioxidant enzyme activity, lowering ROS and cell apoptosis. Furthermore, after being treated with Se-PCS, Caenorhabditis elegans survived longer under Mn stress. daf-16, a tolerant critical gene, was turned on. Moreover, the antioxidant system was enhanced as the increase in strong antioxidant enzyme activity and high expression of the sod-3, ctl-2, and gst-1 genes. A variety of mutations were also used to confirm that Se-PCS downregulated the insulin signaling pathway. These findings showed that Se-PCS protected Hep G2 cells and C. elegans via the insulin/IGF-1 signaling pathway and that it could be developed into a promising medication to treat Mn toxicity.

Acid-Catalyzed Water Extraction of Two Polysaccharides from Artemisia argyi and Their Physicochemical Properties and Antioxidant Activities

In this study, two purified polysaccharide fractions, Artp1 and Artp2, were obtained using acid-catalyzed water extraction, and then purified by DEAE-52 cellulose and Sephadex G-200 column chromatography from the crude polysaccharides of Artemisia argyi. Their physicochemical properties were investigated by gel permeation chromatography (GPC), high-performance anion exchange chromatography (HPAEC), Fourier transform infrared (FT-IR), scanning electron microscope (SEM), thermal analysis, and methylation analysis. The average molecular weight (Mw) of Artp1 and Artp2 were estimated to be 42.17 kDa and 175.22 kDa, respectively. Monosaccharide composition analysis revealed that the Rha, Gal, and GalA occupied main proportion in Artp1 with the molar ratio of 25.1:24.7:40.4, while the Rha, Gal, Xly, and GalA occupied the main proportion in Artp2 with the molar ratio of 16.7:13.5:12.8:38.7. Due to the high yield and the relatively high carbohydrate content, the Artp1 was determined by the methylation analysis and NMR. The results of Artp1 indicated that 1,4-GalpA and 1,2,4-Rhap formed the backbone with some 1,2-Rhap, 1,3-Galp, and 1,6-Galp in the backbone or the side chains. Artp1 and Artp2 exhibited effective antioxidant activities by DPPH radical scavenging assay and hydroxyl radical scavenging assay in a dose-dependent manner. These investigations of the polysaccharides from A. argyi. provide a scientific basis for the uses of Artp1 and Artp2 as ingredients in functional foods and medicines.

Pharmacological Investigations in Traditional Utilization of Alhagi maurorum Medik. in Saharan Algeria: In Vitro Study of Anti-Inflammatory and Antihyperglycemic Activities of Water-Soluble Polysaccharides Extracted from the Seeds

The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from Alhagi&nbsp;maurorum Medik. seeds, spontaneous shrub collected in Southern of Algerian Sahara were investigated. Their water extraction followed by alcoholic precipitation was conducted to obtain two water-soluble polysaccharides extracts (WSPAM1 and WSPAM2). They were characterized using Fourier transform infrared, ¹H/¹³C Nuclear Magnetic Resonance, Gas Chromatography-Mass Spectrometry and Size Exclusion Chromatography coupled with Multi-Angle Light Scattering. The capacity of those fractions to inhibit α-amylase activity and thermally induced Bovine Serum Albumin denaturation were also investigated. WSPAM1 and WSPAM2 were galactomannans with a mannose/galactose ratio of 2.2 and 2.4, respectively. The SEC-MALLS analysis revealed that WSPAM1 had a molecular weight of 1.4 × 10⁶ Da. The investigations highlighted antinflammatory and antihyperglycemic effects in a dose-dependant manner of WSPAM1 and WSPAM2.

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.

Polysaccharides from the Fleshy Fruits of Camellia oleifera Attenuate the Kidney Injury in High-Fat Diet/Streptozotocin-Induced Diabetic Mice

The fleshy fruits of Camellia oleifera Abel are the immature fruits of C. oleifera, which are infected by Exobasidium vexans Massee and then turn to be intumescent and hollowed. They contain rich trace elements and vitamin C and are eaten directly as wild fruits in the Chinese countryside. Recent studies report that C. oleifera has anti-inflammatory and antioxidative effects. The current study, for the first time, evaluates the renal protective capacity of polysaccharides from the fleshy fruits of C. oleifera (CFFP) in streptozotocin-induced diabetic mice fed high-fat diets. The diabetic mice were orally administered CFFP for 3 months to evaluate the renoprotective function of CFFP. Our results indicated that 250 mg/kg CFFP significantly alleviated diabetes-induced renal injury by decreasing serum creatine, blood urea nitrogen levels, the kidney/body weight ratio, expression of fibronectin and collagen, as well as the secretion of tumor necrosis factor-α and interleukin-6. Additionally, 250 mg/kg CFFP could significantly ameliorate renal oxidative stress through increasing glutathione levels and lowering malondialdehyde contents. We confirmed that CFFP could exert antioxidative, anti-inflammatory, and antifibrosis activities. CFFP might be a potential therapeutic agent, and the fleshy fruits of C. oleifera might be a diet therapy for diabetic patients in the future.

A novel low-molecular-mass pumpkin polysaccharide: Structural characterization, antioxidant activity, and hypoglycemic potential

The novel natural low-molecular-mass polysaccharide (SLWPP-3) from pumpkin (Cucurbia moschata) was separated from the waste supernatant after macromolecular polysaccharide production and purified using a DEAE cellulose-52 column and gel-filtration chromatography. Chemical and instrumental studies revealed that SLWPP-3 with a molecular mass of 3.5 kDa was composed of rhamnose, glucose, arabinose, galactose and uronic acid with a weight ratio of 1: 1: 4: 6: 15, and primarily contained →3,6)-β-d-Galp-(1→, →4)-α-GalpA-(1→(OMe), →4)-α-GalpA-(1→, →2,4)-α-d-Rhap-(1→, →3)-β-d-Galp-(1→, →4)-α-d-Glcp, and →4)-β-d-Galp residues in the backbone. The branch chain passes were connected to the main chain through the O-4 atom of glucose and O-3 atom of arabinose. Physiologically, the ability of SLWPP-3 to inhibit carbohydrate-digesting enzymes and DPPH and ABTS radicals, as well as protect pancreatic β cells from oxidative damage by decreasing MDA levels and increasing SOD activities, was confirmed. The findings elucidated the structural types of pumpkin polysaccharides and revealed a potential adjuvant natural product with hypoglycemic effects.

The Effect of Camellia oleifera Cake Polysaccharides on Growth Performance, Carcass Traits, Meat Quality, Blood Profile, and Caecum Microorganisms in Yellow Broilers

Simple Summary

Plant originated polysaccharides used as feed additives have gradually become popular for the health and nutrition of broilers. In the present study, polysaccharides from Camellia oleifera cake (CCP) were added to the daily diet of yellow broilers. Our results indicated that the immunity of the broilers was boosted due to the increasing weight or index of gizzard, spleen, and the thymus. CCP treatment improved the juiciness and changed the meat color of broilers by increasing the cooking loss and the yellowness. Additionally, the structure of intestinal flora altered as a response to the CCP supplementation, which favored the health of broilers. Results have revealed that CCP has potential and development value as a new type of feed additive for broilers.

Abstract

The study was carried out to evaluate the influence of polysaccharides from Camellia oleifera cake (CCP) in Lingnan yellow broilers diet from 1 to 50 days. Growth performance, carcass traits, meat quality, blood profile, and caecum microorganisms were characterized by three different levels of 0, 200 and 800 mg/kg CCP supplementation. Dietary treatment did not affect the productive trait from 1 to 50 days of age, except that average daily feed intake decreased at 42 days of age (p < 0.05). Additionally, the effects of CCP on various organs were different. The weight (p < 0.01) and index (p < 0.05) of bursa of Fabricius gradually decreased with the higher CCP supplementation at 21 days of the broilers diet. The gizzard weights were all higher when the broilers were fed with higher CCP concentration at 21, 42, and 50 days, respectively (p < 0.05). The weight and index of the spleen increased most with low CCP concentration (200 mg/kg) at 42 and 50 days. Moreover, CCP addition had no significant effect on meat quality except cooking loss (P < 0.05) and yellowness of meat color (p < 0.05). In the study of blood metabolism at 50 days of broilers, the concentration of calcium (p < 0.01), total cholesterol (p < 0.05) and uric acid (p < 0.01) decreased with higher CCP supplementation. CCP increased the albumin concentration (p < 0.001) that was highest at 200 mg/kg CCP supplementation. The addition of CCP increased the number of Lactobacillus and Enterococcus faecalis (p < 0.01) in the caecum of broilers, and had the potential to inhibit the growth of Escherichia coli (p = 0.11). Results showed that CCP played a role in improving intestinal flora and the immunity of yellow broilers.

Complementary transcriptome and proteome profiling in the mature seeds of Camellia oleifera from Hainan Island

Camellia oleifera Abel. (C. oleifera), as an important woody tree species producing edible oils in China, has attracted enormous attention due to its abundant unsaturated fatty acids and their associated benefits to human health. To reveal novel insights into the characters during the maturation period of this plant as well as the molecular basis of fatty acid biosynthesis and degradation, we conducted a conjoint analysis of the transcriptome and proteome of C. oleifera seeds from Hainan Island. Using RNA sequencing (RNA-seq) technology and shotgun proteomic method, 59,391 transcripts and 40,500 unigenes were obtained by TIGR Gene Indices Clustering Tools (TGICL), while 1691 protein species were identified from Mass Spectrometry (MS). Subsequently, all genes and proteins were employed in euKaryotic Orthologous Groups (KOG) classification, Gene Ontology (GO) annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis to investigate their essential functions. The results indicated that the most abundant pathways were biological metabolic processes. There were 946 unigenes associated with lipid metabolism at the transcriptome level, with 116 proteins at the proteome level; among these, 38 specific proteins were involved in protein-protein interactions, with the majority being related to fatty acid catabolic process. The expression levels of 21 candidate unigenes encoding target proteins were further detected by quantitative real-time polymerase chain reaction (qRT-PCR). Finally, Gas Chromatography Mass Spectrometry (GC-MS) was carried out to determine the fatty acid composition of C. oleifera oil. These findings not only deepened our understanding about the molecular mechanisms of fatty acid metabolism but also offered new evidence concerning the roles of relevant proteins in oil-bearing crops. Furthermore, the lipid-associated proteins recognized in this research might be helpful in providing a reference for the synthetic regulation of C. oleifera oil quality by genetic engineering techniques, thus resulting in potential application in agriculture.

The non-saponin fraction of Korean Red Ginseng (KGC05P0) decreases glucose uptake and transport in vitro and modulates glucose production via down-regulation of the PI3K/AKT pathway in vivo

Background

The non-saponin fraction of Korean Red Ginseng has been reported to have many biological activities. However, the effect of this fraction on anti-diabetic activity has not been elucidated in detail. In this study, we investigated the effects of KGC05P0, a non-saponin fraction of Korean Red Ginseng, on anti-diabetic activity in vitro and in vivo.

Methods

We measured the inhibition of commercially obtained α-glucosidase and α-amylase activities in vitro and measured the glucose uptake and transport rate in Caco-2 cells. C57BL/6J mice and C57BLKS/J^db/db (diabetic) mice were fed diets with or without KGC05P0 for eight weeks. To perform the experiments, the groups were divided as follows: normal control (C57BL/6J mice), db/db control (C57BLKS/J^db/db mice), positive control (inulin 400 mg/kg b.w.), low (KGC05P0 100 mg/kg b.w.), medium (KGC05P0 200 mg/kg b.w.), and high (KGC05P0 400 mg/kg b.w.).

Results

KGC05P0 inhibited α-glucosidase and α-amylase activities in vitro, and decreased glucose uptake and transport rate in Caco-2 cells. In addition, KGC05P0 regulated fasting glucose level, glucose tolerance, insulin, HbA1c, carbonyl contents, and proinflammatory cytokines in blood from diabetic mice and significantly reduced urinary glucose excretion levels. Moreover, we found that KGC05P0 regulated glucose production by down-regulation of the PI3K/AKT pathway, which inhibited gluconeogenesis.

Conclusion

Our study thereby demonstrated that KGC05P0 exerted anti-diabetic effects through inhibition of glucose absorption and the PI3K/AKT pathway in in vitro and in vivo models of diabetes. Our results suggest that KGC05P0 could be developed as a complementary food to help prevent T2DM and its complications.

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

Psidium guajava fruit is a subtropical fruit, functional food and traditional medicine for the adjuvant treatment of diabetes mellitus in China. To investigate the active components responsible for its health benefits, a novel heteropolysaccharide GP70-3 was purified by water extraction, ethanol precipitation and column chromatography. Structural characterization of GP70-3 was elucidated for the first time by monosaccharide composition assay, Fourier transform-infrared spectroscopy (FT-IR), methylation analysis, gas chromatography coupled with mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). The data revealed that GP70-3 contained a backbone of 1→3,6)-linked β-d-Galp, 1→5)-linked α-l-Araf, 1→6)-linked β-d-Galp and 1→3)-linked β-d-Galp, branched with 1→2,3,5)-linked α-l-Araf, 1→3)-linked α-l-Araf, 1→3)-linked α-l-Rhap, 1→3)-linked β-d-GlcpA, 1→3)-linked β-d-GalpA and terminated with →1)-linked β-d-Galp. Advanced structure studies showed GP70-3 consisted of irregular flakes with rounded-spherical pores. Moreover, GP70-3 exhibited outstanding α-glucosidase inhibitory activity in vitro, with an IC50 value of 2.539 ± 0.144 μM, which was 1867 times higher than that of the positive control acarbose (IC50 value of 4.744 ± 0.026 mM). Therefore, consumption of guava polysaccharides may be beneficial as an α-glucosidase inhibitor for reducing the postprandial blood glucose level and treating type II diabetes.

Structure Characterization and Hypoglycaemic Activities of Two Polysaccharides from Inonotus obliquus

In the present study, two polysaccharides (HIOP1-S and HIOP2-S) were isolated and purified from Inonotus obliquus using DEAE-52 cellulose and Sephadex G-100 column chromatography. The structural characterization and in vitro and in vivo hypoglycaemic activities of these molecules were investigated. HPLC analysis HIOP1-S was a heterpolysaccharide with glucose and galactose as the main compontent monosaccharides (50.247%, molar percentages). However, HIOP2-S was a heterpolysaccharide with glucose as the main monosaccharide (49.881%, molar percentages). The average molecular weights of HIOP1-S and HIOP2-S were 13.6 KDa and 15.2 KDa, respectively. The β-type glycosidic bond in HIOP1-S and HIOP2-S was determined using infrared analysis. ¹H-NMR spectra indicated that HIOP2-S contains the β-configuration glycosidic bond, and the glycoside bonds of HIOP1-S are both α-type and β-type. The ultraviolet scanning showed that both HIOP1-S and HIOP2-S contained a certain amount of binding protein. Congo red test showed that HIOP1-S and HIOP2-S could form a regular ordered triple helix structure in the neutral and weakly alkaline range. HIOP1-S and HIOP2-S showed strong α-glucosidase inhibitory activities and increased the glucose consumption of HepG2 cells. In addition, Streptozotocin (STZ)-induced hyperglycaemic mice were used to evaluate the antihyperglycaemic effects of HIOP1-S and HIOP2-S in vivo. The results showed that HIOP2-S had antihyperglycaemic effects. Taken together, these results suggest that HIOP1-S and HIOP2-S have potential anti-diabetic effects.

Hypoglycemic activity in vitro of polysaccharides from Camellia oleifera Abel. seed cake

We isolated and purified polysaccharide from the Camellia oleifera Abel. seed cake (CCP) and studied its hypoglycemic activity in vitro. The molecular weight of CCP was 4736 Da and the monosaccharide molar composition ratio was: Xylose:Glucuronic acid:Galactosamine:Mannose = 10.9:4.4:2.6:1.8. The CCP contained conjugated proteins and belonged to acidic polysaccharide, which can promote the consumption of the glucose in the medium by HepG2 cells within the range of 0.125-0.500 mg/mL. Relative consumption rate (RCR) of the glucose was the highest at 0.5 mg/mL, exceeded that of the metformin hydrochloride, as well as that of Tea Polysaccharide under the same concentration. A meaningful structure activity relationship (SAR) of hypoglycemia polysaccharides had established. This result suggests that CCP can be used as hypoglycemic medicine or health food.

Structural characterization of a novel acidic polysaccharide from Rosa roxburghii Tratt fruit and its α-glucosidase inhibitory activity

An acidic polysaccharide (RTFP-3) extracted from Rosa roxburghii Tratt fruit can inhibit the activity of α-glucosidase.

Plant non-starch polysaccharides that inhibit key enzymes linked to type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), a metabolic disease becoming ever more common, is the result of disturbed glyco- and lipid metabolism. On the basis of their inhibitory effects against several key enzymes linked to T2DM, synthetic antidiabetic agents have been developed and used for diabetic therapy, some with adverse side effects. Fortunately, many plant non-starch polysaccharides (NSPs) have been shown to possess inhibitory effects on the same T2DM-related enzymes. Through a simple literature search we found that α-amylase, α-glucosidase, lipase, and dipeptidyl-peptidase IV are the enzymes most often reported in the context of T2DM. In this short review we discuss published evidence for inhibition of these enzymes and the implications for treating T2DM.

Physicochemical characterization of the oolong tea polysaccharides with high molecular weight and their synergistic effects in combination with polyphenols on hepatocellular carcinoma

This study was to investigate the synergistic effects of polysaccharides with the molecular weight more than 80kDa (OTPS1) and polyphenols (OTP) isolated from oolong tea on hepatocellular carcinoma (HCC) in vitro and in vivo. The physicochemical properties of OTPS fractions were characterized. The synergistic effects of OTPS1 and OTP were evaluated based on the combination index (CI). Results showed that the highest uronic acid contents (32.96%) and viscosity (239.56mLg^-1), multicavity structure of OTPS1 were contributed to the synergistic effects with OTP (52.17% content of epigallocatechin-3-gallate (EGCG)). OTPS1 and OTP showed the strongest synergism ability on SMMC7721 cells (CI<0.2). Co-administrated with OTPS1 and OTP exhibited the synergistic effects on the tumor proliferation and growth with the CI values of 0.34 and 0.39, respectively. Antioxidative and immune levels of the mice were obviously increased after combination administration. These results suggested that OTPS1 in combination with OTP might be functional supplements for the treatment of HCC.

Physicochemical Characterisation of Polysaccharides from the Seeds and Leaves of Miracle Fruit (Synsepalum dulcificum) and Their Antioxidant and α-Glucosidase Inhibitory Activities In Vitro

Miracle fruit (Synsepalum dulcificum) has been well known and studied for its unique taste-modifying ability. In this study, the monosaccharide composition, molecular weight (Mw), and in vitro bioactivities (antioxidant, α-glucosidase inhibition) of polysaccharides from the seeds (MFP-S) and leaves (MFP-L) of miracle fruit were investigated. The results showed that MFP-S was a homogeneous polysaccharide (Mw 2804 Da) with glucose. MFP-L displayed three fractions (92093, 1496, and 237 Da) consisting of rhamnose, arabinose, galactose, glucose, and xylose. Moreover, the antioxidant and α-glucosidase inhibition of MFP-L were significantly greater than those of MFP-S. The α-glucosidase inhibition of MFP-L was remarkably better than the positive control, acarbose (an antidiabetes drug). More specifically, the 50% inhibitory concentration (IC50) values of α-glucosidase activities for MFP-S, MFP-L, and acarbose were 33, 0.01, and 1 mg mL−1, separately. Therefore, MFP-L can be developed as a functional factor with both antioxidant and antidiabetes activities in food applications.

Anti-diabetic polysaccharides from natural sources: A review

Diabetes mellitus (DM) is a metabolic disease attracted worldwide concerns, which severely impairs peoples' quality of life and is attributed to several life-threatening complications, including atherosclerosis, nephropathy and retinopathy. The current therapies for DM include mainly oral anti-diabetic drugs and insulin. However, continuous use of these causes insulin resistance and side-effects, and the demand of effective, nontoxic and affordable drugs for DM patients is eager. Several previous studies have shown that non-toxic biological macromolecules, mainly polysaccharides, possess prominent efficacies on DM. Based on these encouraging observations, a great deal of efforts have been focused on discovering anti-diabetic polysaccharides for the development of effective therapeutics for DM. This review focuses on the advancements in the anti-diabetic efficacy of various natural polysaccharides and polysaccharide complexes from 2010 to 2015.