Metabolism amelioration of Dendrobium officinale polysaccharide on type II diabetic rats

Trichosanthes kirilowii Maxim. Polysaccharide attenuates diabetes through the synergistic impact of lipid metabolism and modulating gut microbiota

Polysaccharide, a chain of sugars bound by glycosidic bonds, have a wide range of physiological activities, including hypoglycemic activity. In present study, we established T2DM mice models to explore the effects and mechanism of Trichosanthes kirilowii Maxim polysaccharide (TMSP1) on high-fat diet/streptozotocin (HF-STZ) induced diabetes mice. The results showed that high-fat diet significantly increased the oral glucose tolerance test (OGTT), viscera index, oxidative stress, impaired glucose tolerance, decreased body weight, immune response and short-chain fatty acid (SCFAs) content, and disrupted the balance of intestinal flora structure. However, after 6 weeks of TMSP1 intervention decreased lipid accumulation, ameliorated gut microbiota dysbiosis by increasing SCFAs-producing bacteria and mitigated intestinal inflammation and oxidative stress. Moreover, TMSP1 significantly restored the integrity of the intestinal epithelial barrier and mucus barrier. The results of fecal microbiota transplantation confirmed that TMSP1 exerted hypoglycemic effect through regulating intestinal flora to a certain extent. Collectively, the findings revealed TMSP1 intervention inhibits hyperglycemia by improving gut microbiota disorder, lipid metabolism, and inflammation. Hence, TMSP1 may be an effective measure to ameliorate HF-STZ induced diabetes.

Hypoglycemic activity of enzymatically extracted Eucommia ulmoides polysaccharide (EUL-w1) on IR-HepG2 cell via the AMPK/PI3K/Akt signaling pathway

This study devised optimal conditions to extract Eucommia ulmoides leaf (EUL) polysaccharides using a cellulase and pectinase composite enzyme system based on one-way experiments and response surface methodology. Crude EUL polysaccharides (EULPs) were extracted and purified using a DEAE chromatography column. The polysaccharides EUL-w, EUL1, EUL2, and EUL3 were obtained by elution with water, 0.1 mol/L NaCl, 0.2 mol/L NaCl, and 0.3 mol/L NaCl, respectively. The EUL-w fraction had the highest hypoglycemic activity based on its α-amylase and α-glucosidase activities. The preliminary structure of purified EUL-w1 was elucidated. In vitro hypoglycemic activity studies and metabolomics analyses suggested that EUL-w1 modulated glucose metabolism by mediating the AMPK/PI3K/Akt signaling pathway. Our findings provide novel insights and data support for the utilization of EULPs as an emerging food resource in functional foods.

Ultrasonic Extraction of Polysaccharides from Dendrobium officinale Leaf: Kinetics, In Vitro Activities, and Characterization

This study explored the kinetics of ultrasonic extraction of polysaccharides (DOLP) from Dendrobium officinale leaf (DOL), evaluated the in vitro bioactivity of DOL extracts and DOLP, and characterized the DOLP. A kinetic model was developed based on Fick's second law. A technique utilizing 400 W for 50 min was employed for the ultrasonic extraction of DOLP, with an optimal solid-liquid ratio established at 1:40 (g/mL). DOL extracts dried using different methods exhibited varying antioxidant activity and inhibitory effects against α-amylase and α-glucosidase. An in vitro study revealed that DOL extracts obtained through vacuum freeze drying demonstrated significantly stronger antioxidant activity, while those derived through microwave drying showed superior inhibitory effects against α-amylase and α-glucosidase compared to the other two drying methods. Furthermore, it was observed that the in vitro bioactivity of DOLP (purity: 74.07 ± 0.52%) was significantly lower than that of DOL extracts. Nevertheless, DOLP (5.0 mg/mL) demonstrated a scavenging ability reaching 64.86% of VC for DPPH radical and 67.14% of VC for ·OH radical, and the inhibition of DOLP (10 mg/mL) on α-amylase and α-glucosidase reached 58.40% and 38.28% of the acarbose, respectively. The findings revealed that DOLP are predominantly composed of mannose, glucose, galactose, and arabinose in a distinctive molar ratio of 89.00:16.33:4.78:1.

The general glycan profiling of Dendrobium officinale and their protective effects on MIN6 cells via ERK signaling pathway

Based on structural elucidation of natural and hydrolyzed glycans, the general glycans profiling of D. officinale were unequivocally established for the first time as follows: The results indicated that the structure of D. officinale glycans with low degree of polymerization (DP ≤ 22) was linear α-D-1,4-glucan, whereas the structure of glycans with high degree of polymerization (DP > 24) was linear acetylated 1,4-glucomannan. The content of acetyl groups and mannose to glucose (M/G) ratio increased with the degree of polymerization of D. officinale glycans. In addition, this study showed that natural D. officinale glycans protected pancreatic β-cell damage induced by glucotoxicity through the extracellular signal-regulated kinase (ERK)1/2 pathway.

Polysaccharide NAP-3 Synergistically Enhances the Efficiency of Metformin in Type 2 Diabetes via Bile Acid/GLP-1 Axis through Gut Microbiota Remodeling

The polysaccharides of edible mushrooms are excellent phytochemicals for adjuvant treatment of metabolic diseases, but the potential mechanisms of synergistic effects are unclear. In this work, we discovered that NAP-3 enhanced the efficiency of metformin in lipid and glucose metabolism in type 2 diabetic (T2D) mice in a gut microbiome-dependent way. NAP-3 remodeled the intestinal microbial, resulting in the decreased activity of bile salt hydrolases and upregulation of CYP27A1 and CYP7B1 functions in the alternative pathway of bile acid synthesis, which leads to accumulation of the conjugated bile acids in ileum, specifically TβMCA and TUDCA. The accumulated conjugated bile acids either blocked or stimulated the nuclear receptors Farnesoid-X-receptor and TGR5, inducing the release of GLP-1 and ultimately enhanced glucose metabolism in mice. Collectively, our research indicated that edible mushroom polysaccharide NAP-3 may serve as a promising adjunctive oral therapeutic agent for T2D.

Structural characterization and hypoglycemic effect of polysaccharides of Polygonatum sibiricum

Polygonatum sibiricum polysaccharide (PSP) was extracted and purified from raw material obtained from P. sibiricum. The structural features of PSP were investigated by Congo red, circular dichroism spectrum, high-performance gel permeation chromatography, scanning electron microscope, atomic force microscope, ultraviolet spectroscopy, and Fourier transform infrared spectroscopy analysis. In vitro simulations were conducted to investigate the kinetics of PSP enzyme inhibition. Moreover, a type II diabetes mouse model (T2DM) with streptozotocin-induced insulin resistance was established, and the indexes of lipid quadruple, insulin resistance index, oral glucose tolerance (OGTT), organ index, and pancreatic morphology of model mice were measured. The results showed that PSP mainly consists of monosaccharides, such as mannose, glucose, galactose, xylose, and arabinose. It also has a β-glycosidic bond of a pyranose ring and an irregular reticulated aggregated structure with a triple helix. In vitro enzyme inhibition assays revealed that PSP acts as a reversible competitive inhibitor of α-glucosidase and α-amylase. Furthermore, PSP was found to reduce insulin resistance index, increase OGTT and serum insulin levels, decrease free fatty acid content to improve lipid metabolism, and lower glycated serum protein content to enhance glucose metabolism in T2DM mice, thereby leading to a reduction in blood glucose concentration. Additionally, PSP exhibited reparative effects on the damaged liver tissue cells and pancreatic tissue in T2DM mice. The experiment results provide a preliminary basis for the therapeutic mechanism of PSP about type II diabetes and a theoretical reference for application in food and pharmaceutical development.

Paper-based ligand fishing method for rapid screening and real-time capturing of α-glucosidase inhibitors from the Chinese herbs

Identifying medicinally relevant compounds from natural resources generally involves the tedious work of screening plants for the desired activity before capturing the bioactive molecules from them. In this work, we created a paper-based ligand fishing platform to vastly simplify the discovery process. This paper-based method exploits the enzymatic cascade reaction between α-glucosidase (GAA), glucose oxidase (GOx), and horseradish peroxidase (HRP), to simultaneously screen the plants and capture the GAA inhibitors from them. The designed test strip could capture ligands in tandem with screening the plants, and it features a very simply operation based on direct visual assessment. Multiple acylated flavonol glycosides from the leaves of Quercus variabilis Blume were newly found to possess GAA inhibitory activities, and they may be potential leads for new antidiabetic medications. Our study demonstrates the prospect of the newly discovered GAA ligands as potential bioactive ingredients as well as the utility of the paper-based ligand fishing method.

Variations in Cold Resistance and Contents of Bioactive Compounds among Dendrobium officinale Kimura et Migo Strains

Dendrobium officinale is a valuable traditional Chinese herbal plant that is both medicinal and edible. However, the yield of wild Dendrobium officinale is limited. Adverse stress affects the growth, development, and yield of plants, among which low temperature is the primary limiting factor for introducing Dendrobium officinale to high-latitude areas and expanding the planting area. Therefore, this study aims to explore the variations in growth ability, cold resistance, and contents of bioactive compounds among different Dendrobium officinale strains. Four strains of Dendrobium officinale were selected as experimental materials and were subjected to low-temperature stress (4 °C). The agronomic traits, physiological indices, as well as the expressions of cold resistance-related genes (HSP70, DcPP2C5, DoCDPK1, and DoCDPK6) in the roots and leaves of Dendrobium officinale, were determined. The contents of bioactive compounds, including polysaccharides, flavonoids, and phenols were also measured. Compared with the other strains, Xianju had the highest seed germination and transplantation-related survival rates. Under low-temperature stress, Xianju exhibited the strongest cold resistance ability, as revealed by the changes in water contents, chlorophyll levels, electrical conductivities, enzyme activities, and expressions of the cold resistance-related genes. Additionally, the polysaccharide content of Xianju increased the most, while the stem flavonoid and leaf phenol contents were elevated in all four strains under cold treatment. Therefore, selecting excellent performing strains is expected to expand the planting area, improve the yield, and increase the economic benefits of Dendrobium officinale in high latitude areas with lower temperatures.

"MD" method for the precise analysis of the O-acetyl-mannan structure and disclosure of the role in the conformational stability of insulin

Among the diversified glycan modifications, acylation is one of the most abundant. This modification could be responsible for many of the properties of glycans, such as structural stability and specificity for biological activity. To obtain better insight into the effects of acetylation of glycans on the structure and thermostability of insulin, it is critical to investigate glycans with a high degree of acetylation. An in-depth study of three functional glycans named acetyl-mannan from Dendrobium devonianum (DDAM) was conducted herein by efficient enzymatic depolymerization, and the effect of glycosidic bonds on acetylation modification sites was studied through a molecular dynamics (MD) method, as well as its positive effect on insulin secretion, glucose uptake, and the thermal stability of tertiary structures in vitro. Further study indicated that DDAMs play a hypoglycemic role by sparking the thermostability of the insulin conformation. The hypoglycemic activity displayed a positive correlation with the degree of acetylation in DDAMs. In this work, through the MD method, we confirmed the structure characteristics of DDAMs and provided accurate data support for the structure-activity relationship analysis. Thus, these findings demonstrated that DDAMs might be an exceptional leading compound for the stability of insulin drug.

Nanotechnology-based Herbal Drug Formulation in the Treatment of Diabetes Mellitus

The utilization of nanotechnology-based herbal medication delivery systems is gaining attention as a novel approach to treating diabetes mellitus. The incorporation of nanotechnology into herbal medicine provides benefits such as enhanced Stability, solubility, and bioavailability of herbal medications. The purpose of this paper is to summarise the present status of research on herbal medicine delivery systems based on nanotechnology for the treatment of diabetic patients. The paper evaluates the various nanocarriers and herbal drugs used, the challenges and opportunities in the development of these systems, and their potential efficacy and safety. Additionally, the paper highlights the need for further research to optimize the formulation and delivery of these systems. This review's overarching objective is to provide a complete understanding of the possibilities of herbal medication delivery systems based on nanotechnology in diabetes mellitus treatment.

Comprehensive evaluation of the prebiotic properties of Dendrobium officinale polysaccharides, β-glucan, and inulin during in vitro fermentation via multi-omics analysis

Dietary fiber is crucial for human health mainly due to its impact on gut microbiota structure and metabolites. This study aimed to investigate the impact of Dendrobium officinale polysaccharides (DOP) and two common fibers (β-glucan and inulin) on the gut microbiome structure and metabolic profile in vitro. Fecal samples were obtained from 30 healthy volunteers, which were then individually subjected to fermentation with each type of fiber. The results revealed that all fibers were efficiently degraded by gut microbiota, with DOP exhibiting a slower fermentation rate compared to β-glucan and inulin. The fermentation of all fibers led to a significant increase in the production of short-chain fatty acids (SCFAs) and a reduction in branched-chain fatty acids (BCFAs), sulfides, phenols, and indole. Moreover, the abundance of unclassified Enterobacteriaceae, which was positively correlated with sulfide, phenols, and indole levels, was significantly reduced by all fibers. Additionally, DOP specifically promoted the growth of Parabacteroides, while β-glucan and inulin promoted the growth of Bifidobacterium and Faecalibacterium. Taken together, these findings enhance our understanding of the role of DOP, β-glucan, and inulin in modulating gut microbiota and metabolites, where the fermentation with fecal bacteria from different volunteers could provide valuable insights for personalized therapeutic approaches.

Preclinical pharmacokinetics-related pharmacological effects of orally administered polysaccharides from traditional Chinese medicines: A review

Polysaccharides (TCMPs) derived from traditional Chinese medicines (TCMs), such as Ganoderma lucidum, Astragalus membranaceus, Lycium barbarum, and Panax ginseng, are considered to be the main active constituents in TCMs. However, the significant pharmacological effects of orally administered TCMPs do not align well with their poor pharmacokinetics. This article aims to review the literature published mainly from 2010 to 2022, focusing on the relationship between pharmacokinetics and pharmacological effects. It has been found that unabsorbed TCMPs can exert local pharmacological effects in the gut, including anti-inflammation, anti-oxidation, regulation of intestinal flora, modulation of intestinal immunity, and maintenance of intestinal barrier integrity. Unabsorbed TCMPs can also produce systemic pharmacological effects, such as anti-tumor activity and immune system modulation, by regulating intestinal flora and immunity. Conversely, some TCMPs can be absorbed and distributed to various tissues, especially the liver, where they exhibit tissue-protecting effects against inflammation and oxidative stress-induced damage and improve glucose and lipid metabolism. In future studies, it is important to improve quality control and experimental design. Furthermore, research on enhancing the oral bioavailability of TCMPs, exploring the activity of TCMP metabolites, investigating pharmacokinetic interactions between TCMPs and oral drugs, and developing oral drug delivery systems using TCMPs holds great significance.

Structure, Health Benefits, Mechanisms, and Gut Microbiota of Dendrobium officinale Polysaccharides: A Review

Dendrobium officinale polysaccharides (DOPs) are important active polysaccharides found in Dendrobium officinale, which is commonly used as a conventional food or herbal medicine and is well known in China. DOPs can influence the composition of the gut microbiota and the degradation capacity of these symbiotic bacteria, which in turn may determine the efficacy of dietary interventions. However, the necessary analysis of the relationship between DOPs and the gut microbiota is lacking. In this review, we summarize the extraction, structure, health benefits, and related mechanisms of DOPs, construct the DOPs-host axis, and propose that DOPs are potential prebiotics, mainly composed of 1,4-β-D-mannose, 1,4-β-D-glucose, and O-acetate groups, which induce an increase in the abundance of gut microbiota such as Lactobacillus, Bifidobacterium, Akkermansia, Bacteroides, and Prevotella. In addition, we found that when exposed to DOPs with different structural properties, the gut microbiota may exhibit different diversity and composition and provide health benefits, such as metabolism regulations, inflammation modulation, immunity moderation, and cancer intervention. This may contribute to facilitating the development of functional foods and health products to improve human health.

Hypoglycemic effects of dendrobium officinale leaves

Introduction: Numerous studies have demonstrated that the stems of D. officinale have the effect of lowering blood glucose, but the leaves of D. officinale have seldom been investigated. In this study, we mainly studied the hypoglycemic effect and mechanism of D. officinale leaves. Methods: Initially in vivo, male C57BL/6 mice were administered either standard feed (10 kcal% fat) or high-fat feed (60 kcal% fat) along with either normal drinking water or drinking water containing 5 g/L water extract of D. officinale leaves (EDL) for 16 weeks, and changes in body weight, food intake, blood glucose, etc., were monitored weekly. Next in vitro, C2C12 myofiber precursor cells which were induced to differentiate into myofibroblasts and cultured with EDL to detect the expression of insulin signaling pathway related proteins. HEPA cells were also cultured with EDL to detect the expression of hepatic gluconeogenesis or hepatic glycogen synthesis related proteins. Eventually after separating the components from EDL by ethanol and 3 kDa ultrafiltration centrifuge tube, we conducted animal experiments using the ethanol-soluble fraction of EDL (ESFE), ethanol-insoluble fraction of EDL (EIFE), ESFE with a molecular weight of >3 kDa (>3 kDa ESFE), and ESFE with a molecular weight of <3 kDa (<3 kDa ESFE) for intensive study. Results: The results in vivo revealed that the mice fed the high-fat diet exhibited significantly decreased blood glucose levels and significantly increased glucose tolerance after the EDL treatment, whereas the mice fed the low-fat diet did not. The results in vitro showed that EDL activated the expression of protein kinase B (AKT), the phosphorylation of AKT, and the expression of downstream GSK3β in the insulin signaling pathway. EDL treatment of HEPA cells confirmed that EDL did not affect hepatic gluconeogenesis or hepatic glycogen synthesis. In the experiment of studying the composition of EDL, we found that the >3 kDa ESFE displayed the effect of lowering blood glucose. In summary, the effect of EDL in lowering blood glucose may bethanole achieved by activating the insulin signaling pathway to increase insulin sensitivity, and the main functional substance was contained within the >3 kDa ESFE. Discussion: The findings of this study represent a reference point for further exploration of the hypoglycemic effects of D. officinale leaves and may assist in both the identification of new molecular mechanisms to improve insulin sensitivity and the isolation of monomeric substances that lower blood glucose. Furthermore, the obtained results may provide a theoretical basis for the development of hypoglycemic drugs with D. officinale leaves as the main component.

The effects of pectin on the gut microbiota and serum metabolites in mice fed with a high fat diet and exposed to low-dose antibiotics

A sedentary lifestyle, unhealthy diet, and antibiotic use among other environmental factors have been associated with an increased incidence of metabolic disorders and inflammation, as well as gut dysbiosis. Pectin is an edible polysaccharide that exists widely in the cell wall of plants. Our previous study has shown that pectin with various degrees of esterification displayed different effects on preventing acute colitis and regulating the gut microbiome and serum metabolome. This study aimed to further explore the differential effects of pectin with various degrees of esterification on mice simultaneously treated with a high-fat diet and low-dose antibiotics. The results showed that low-esterified pectin L102 improved the biomarkers of metabolic disorders including blood glucose and body weight. The high-esterified pectin H121 and the low-esterified pectin L13 ameliorated inflammatory markers such as superoxide dismutase (SOD). The enrichment of probiotic bacteria such as Lactobacillus by pectin L102, reduction of conditional pathogens such as Klebsiella by pectin L13, and changes in circulating metabolites like L-tryptophan and 3-indoleacrylate by all three types of pectins were detected. These data provide evidence for a differential effect of different types of pectin on the gut microbiota and metabolic health.

Current progress in the hypoglycemic mechanisms of natural polysaccharides

Unhealthy dietary pattern-induced type 2 diabetes mellitus poses a great threat to human health all over the world. Accumulating evidence has revealed that the pathophysiology of type 2 diabetes mellitus is closely associated with the dysregulation of glucose metabolism and energy metabolism, serious oxidative stress, prolonged endoplasmic reticulum stress, metabolic inflammation and intestinal microbial dysbiosis. Most important of all, insulin resistance and insulin deficiency are two key factors inducing type 2 diabetes mellitus. Nowadays, natural polysaccharides have gained increasing attention owing to their numerous health-promoting functions, such as hypoglycemic, energy-regulating, antioxidant, anti-inflammatory and prebiotic activities. Therefore, natural polysaccharides have been used to alleviate diet-induced type 2 diabetes mellitus. Specifically, this review comprehensively summarizes the underlying hypoglycemic mechanisms of natural polysaccharides and provides a theoretical basis for the development of functional foods. For the first time, this review elucidates hypoglycemic mechanisms of natural polysaccharides from the perspectives of their regulatory effects on glucose metabolism, insulin resistance and mitochondrial dysfunction.

Modern interpretation of the traditional application of Shihu - A comprehensive review on phytochemistry and pharmacology progress of Dendrobium officinale

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese medicine (TCM) "Shihu" has a long history of medicinal use in China from some species of Dendrobium. D. officinale is a major source of "Shihu" and is widely cultivated in south of China and listed separately as "Tiepi Shihu" by the Chinese Pharmacopoeia in now time. Traditionally, D. officinale has been widely used in daily health care and the treatment of diabetes and gastrointestinal diseases.

AIM OF THIS REVIEW

In order to better develop and utilize D. officinale, we conducted this systematic review of previous studies, showed clear structure of all isolates from D. officinale together with pharmacological progress, hoping to provide references for further research and utilization. In addition, specific display of the chemical components and the research progress of related activities can help to better understand the traditional records and modern pharmaceutical applications of the plant medicine.

MATERIALS AND METHODS

Information on phytochemistry and pharmacological studies of D. officinale was collected from various scientific databases including Web of Science, SciFinder, ACS, Springer, Scopus, PubMed, ScienceDirect, Google Scholar and CNKI.

RESULTS

More than 180 compounds isolated from D. officinale, including bibenzyls, phenols, phenylpropanoids, lignans, flavonoids and polysaccharides are listed in this review. Furthermore, modern pharmacological researches such as hypoglycemia, immune regulation, antioxidant, cardiovascular regulation and gastrointestinal protection are summarized.

CONCLUSION

Based on the summary of the research work of D. officinale, we systematically show the chemical composition of the plant, and concluded the relationship of those composition with plant habitat together with the relationship between the structure of chemical components and pharmacological activity. Moreover, we suggest that some of small molecule compounds could also be quality control of D. officinale besides polysaccharides.

A systematic analysis of anti-diabetic medicinal plants from cells to clinical trials

Background

Diabetes is one of the fastest-growing health emergencies of the 21st century, placing a severe economic burden on many countries. Current management approaches have improved diabetic care, but several limitations still exist, such as decreased efficacy, adverse effects, and the high cost of treatment, particularly for developing nations. There is, therefore, a need for more cost-effective therapies for diabetes management. The evidence-based application of phytochemicals from plants in the management of diseases is gaining traction.

Methodology

Various plants and plant parts have been investigated as antidiabetic agents. This review sought to collate and discuss published data on the cellular and molecular effects of medicinal plants and phytochemicals on insulin signaling pathways to better understand the current trend in using plant products in the management of diabetes. Furthermore, we explored available information on medicinal plants that consistently produced hypoglycemic effects from isolated cells to animal studies and clinical trials.

Results

There is substantial literature describing the effects of a range of plant extracts on insulin action and insulin signaling, revealing a depth in knowledge of molecular detail. Our exploration also reveals effective antidiabetic actions in animal studies, and clear translational potential evidenced by clinical trials.

Conclusion

We suggest that this area of research should be further exploited in the search for novel therapeutics for diabetes.

Capturing the impact of oral processing behavior and bolus formation on the dynamic sensory perception and composition of steamed sturgeon meat

The effect of oral processing on flavor release and change in composition of steamed sturgeon meat was investigated. Oral processing caused changes in the concentrations of taste compounds including amino acids, 5'-nucleotides, organic acids, and Na⁺. Sensory omics demonstrated that the concentrations of 12 volatile compounds increased significantly (p < 0.05) during the initial stage of oral processing. There is no significant difference in microstructure, texture, and particle size of meat bolus. The top fifteen differential lipids which including eight phospholipids in all processed samples significantly (p < 0.05) correlated with the flavor release. A total of 589 differential proteins were detected in three samples with different chewing times (0, 12, and 30 s). Analysis of the correlations between odorants and 19 differential proteins was performed. Enriched pathways including fatty acid degradation, valine, leucine and isoleucine degradation, glycine, serine and threonine metabolism, and arachidonic acid metabolism were associated with flavor release during oral processing. This study aimed to investigate potential links between flavor release and biological processes during oral processing from a proteomics perspective.

Glucomannan in Dendrobium catenatum: Bioactivities, Biosynthesis and Perspective

Dendrobium catenatum is a classical and precious dual-use plant for both medicine and food in China. It was first recorded in Shen Nong's Herbal Classic, and has the traditional functions of nourishing yin, antipyresis, tonifying the stomach, and promoting fluid production. The stem is its medicinal part and is rich in active polysaccharide glucomannan. As an excellent dietary fiber, glucomannan has been experimentally confirmed to be involved in anti-cancer, enhancing immunity, lowering blood sugar and blood lipids, etc. Here, the status quo of the D. catenatum industry, the structure, bioactivities, biosynthesis pathway and key genes of glucomannan are systematically described to provide a crucial foundation and theoretical basis for understanding the value of D. catenatum and the potential application of glucomannan in crop biofortification.

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.

Unravelling the key aroma compounds in the characteristic fragrance of Dendrobium officinale flowers for potential industrial application

Dendrobium officinale Kimura et Migo, one of the most important orchids because of its medicinal and edible value, has a typical Dendrobium Sw. flora scent, which has great application potential and commercial value to be characterized. The aroma-active compounds originating from D. officinale fresh flowers (DFF) were investigated using a sensomics approach. A combined solid phase microextraction and solvent-assisted flavor evaporation method were used to accurately capture the overall aromatic profile. Exactly 34 odorants were detected and identified by aroma extract dilution analysis (AEDA) coupled with gas chromatography/olfactometry-mass spectrometry (GC/O-MS) in DFF, of which nine odorants had a flavor dilution (FD) factor ≥27. All 34 odorants were further quantified. The odor activity values (OAVs) were calculated with the highest value of 7444, in which 18 compounds were confirmed to be key odorants, including 1-octen-3-ol, hexanal, nonanal, phenylacetaldehyde, linalool, 4-oxoisophorone, theaspirane, methyl salicylate, etc. Among the studies above, 42 out of 78 volatiles and 14 out of 34 odorants were identified in DFF for the first time. Then, the aroma profile of the DFF was simulated successfully by aroma recombination experiments based on the quantitation results, and the omission test suggested that alcohols are the decisive type of compounds in the DFF key odorants. In addition, a progressive addition test showed that the aroma recombinate prepared with 18 reference key odorants was able to reconstruct the characteristic aroma of DFF. In comparison, the recombinate constituted by mixing all 34 reference odorants in the same concentrations as determined in the DDF sample could mimic the flower scent and closely match the sensory attributes of the original D. officinale fresh flower.

Research progress on extraction, purification, structure and biological activity of Dendrobium officinale polysaccharides

Dendrobium officinale Kimura et Migo (D. officinale) is a traditional medicinal and food homologous plant that has been used for thousands of years in folk medicine and nutritious food. Recent studies have shown that polysaccharide is one of the main biologically active components in D. officinale. D. officinale polysaccharides possess several biological activities, such as anti-oxidant, heptatoprotective, immunomodulatory, gastrointestinal protection, hypoglycemic, and anti-tumor activities. In the past decade, polysaccharides have been isolated from D. officinale by physical and enzymatic methods and have been subjected to structural characterization and activity studies. Progress in extraction, purification, structural characterization, bioactivity, structure-activity relationship, and possible bioactivity mechanism of polysaccharides D. officinale were reviewed. In order to provide reference for the in-depth study of D. officinale polysaccharides and the application in functional food and biomedical research.

Polysaccharide from Hemerocallis citrina Borani by subcritical water: Bioactivity, purification, characterization, and anti-diabetic effects in T2DM rats

Hemerocallis citrina Borani (daylily) has various health benefits. However, the structural characterization and hypoglycemic effects of its polysaccharide remain unclear. Here, we first report for the first time, the effects of subcritical water extraction temperature on bioactivity of Hemerocallis citrina Borani polysaccharide (HCBP). HCBP extracted at 160 °C had better scavenging ability of free-radical and pancreatic lipase inhibition. This study aimed to investigate the structural characterization and anti-diabetic effects of aforementioned HCBP. HCBP was separated into three fractions using a DEAE-Sepharose Fast Flow. HCBP-1 was the major component with lower molecular weight, HCBP-2 was the least abundant component, HCBP-3 was the component with higher uronic acid and molecular weight. HCBP treatment significantly decreased the concentrations of fasting blood glucose, insulin, total cholesterol, triglyceride, and low density lipoprotein, as well as improved glucose intolerance and insulin resistance in type 2 diabetes mellitus (T2DM) rats. HCBP also protected the kidneys and pancreatic organs by histopathology and immunohistochemical analyses in T2DM rats. In addition, HCBP significantly increased the antioxidant enzymes activities and decreased the level of malonaldehyde to alleviated the oxidative stress injury. The results indicate HCBP extracted by subcritical water is promising functional food ingredients and could be used in T2DM treatment.

A Systematic Review on Polysaccharides from Dendrobium Genus: Recent Advances in the Preparation, Structural Characterization, Bioactive Molecular Mechanisms, and Applications

Dendrobium polysaccharides (DPSs) have aroused people's increasing attention in recent years as a result of their outstanding edible and medicinal values and non-toxic property. This review systematically summarized recent progress in the different preparation techniques, structural characteristics, modification, various pharmacological activities and molecular mechanisms, structure-activity relationships, and current industrial applications in the medicinal, food, and cosmetics fields of DPSs. Additionally, some recommendations for future investigations were provided. A variety of methods were applied for the extraction and purification of DPSs. They possessed primary structures (e.g., glucomannan, rhamnogalacturonan I type pectin, heteroxylan, and galactoglucan) and conformational structures (e.g., random coil, rod, globular, and a slight triple-helical). And different molecular weights, monosaccharide compositions, linkage types, and modifications could largely affect DPSs' bioactivities (e.g., immunomodulatory, anti-diabetic, hepatoprotective, gastrointestinal protective, antitumor, anti-inflammatory, and anti-oxidant activities). It was worth mentioning that DPSs were significant pharmaceutical remedies and therapeutic supplements especially due to their strong immunity enhancement abilities. We hope that this review will lay a solid foundation for further development and applications of Dendrobium polysaccharides.

Noni (Morinda citrifolia L.) Fruit Polysaccharides Regulated IBD Mice Via Targeting Gut Microbiota: Association of JNK/ERK/NF-κB Signaling Pathways

Inflammatory bowel disease (IBD) is a disease characterized by intestinal inflammation with immune dysregulation and intestinal microecological imbalance. In a dextran sulfate sodium salt (DSS)-induced IBD mouse model, noni (Morinda citrifolia L.) fruit polysaccharides (NFP) with homogalacturonan and rhamnogalacturonan-I domain decreased the concentration of serum LPS, TNF-α, and IL-17 by 84, 42, and 65%, respectively. It was abolished when intestinal microbiota were depleted by antibiotics. Sequencing analysis of gut microbiota showed an attenuated disruption of the microbial composition in the DSS+NFP group. Targeted metabolomic analysis revealed that NFP upregulated the content of acetic acid, propionic acid, and butyric acid by onefold but reduced isobutyric acid and isovaleric acid contents. NFP also inhibited JNK, ERK, and NF-κB phosphorylation of IBD mice. Taken together, the mechanism of NFP alleviating IBD is related to the intestinal microecological balance to inhibit inflammatory signaling pathways. This study provides a basis for NFP as a cheap intervention for the prevention and treatment of IBD patients.

Isolation, structural properties, bioactivities of polysaccharides from Dendrobium officinale Kimura et. Migo: A review

Dendrobium officinale Kimura et Migo (D. officinale) is used as herbal medicine and new food resource in China, which is nontoxic and harmless, and can be used as common food. Polysaccharide as one of the main bioactive components in D. officinale, mainly composed of glucose and mannose (Manp: Glcp = 2.01:1.00-8.82:1.00), along with galactose, xylose, arabinose, and rhamnose in different molar ratios and types of glycosidic bonds. Polysaccharides of D. officinale exhibit a variety of biological effects, including immunomodulatory, anti-tumor, gastro-protective, hypoglycemic, anti-inflammatory, hepatoprotective, and vasodilating effects. This paper presents the extraction, purification, structural characteristics, bioactivities, structure-activity relationships and analyzes gaps in the current research on D. officinale polysaccharides. In addition, based on in vitro and in vivo experiments, the possible mechanisms of bioactivities of D. officinale polysaccharides were summarized. We hope that this work may provide helpful references and promising directions for further study and development of D. officinale polysaccharides.

Polysaccharides from fermented Asparagus officinalis with Lactobacillus plantarum NCU116 alleviated liver injury via modulation of glutathione homeostasis, bile acid metabolism, and SCFA production

Lactic acid bacteria strain (LAB) NCU116 fermented Asparagus officinalis polysaccharides (FAOP) have been proven to cause substantial changes in physicochemical properties such as monosaccharide composition and molecular weight, accounting for their enhanced immune activity than unprocessed Asparagus officinalis polysaccharides (AOP). In the current study, the hepatoprotective effects of FAOP in mice with cyclophosphamide (CTX)-induced hepatotoxicity were investigated. FAOP were more effective than AOP in alleviating CTX-induced hepatic damage, including inhibition of hepatic biochemical markers (ALT, AST, AKP and LDH) and pro-inflammatory cytokines (TNF-α and IL-1β) as well as reinforcement of antioxidant systems (T-AOC, SOD, CAT, and MDA). In particular, compared with AOP, FAOP showed superior performance by promoting GSH biosynthesis, and normalizing the expression level of bile acid receptors (FXR and SHP) and key enzymes in bile acid synthesis (CYP7A1, CYP8B1 and CYP27A1). Modulation of disordered homeostasis of bile acids by FAOP can be attributed to the upregulation of hepatic short chain fatty acid (SCFA) receptors GPR41 and GPR109A as well as intestinal SCFA production. Furthermore, serum metabolomics study validated the hepatoprotective superiority of FAOP than AOP with evidence from variations in bile acid compositions and the construction of related metabolic pathways. Therefore, LAB NCU116 fermentation of Asparagus officinalis was practical and effective to obtain promising hepatoprotective polysaccharides, which might arise from enhanced SCFA production than unprocessed AOP.

Polysaccharides from fermented Momordica charantia L. with Lactobacillus plantarum NCU116 ameliorate metabolic disorders and gut microbiota change in obese rats

Obesity is a chronic disease characterized by overweight resulting from fat accumulation, along with disturbance of metabolism and gut microbiota. Fermentation, as a green processing method, is beneficial for improving the nutrition capacity of food components. Polysaccharides are considered as one of the important components in food and are also potential supplements for anti-obesity treatment. This study aimed to investigate the anti-obesity effects of polysaccharides from fermented and non-fermented Momordica charantia L. with Lactobacillus plantarum NCU116 (FP and NFP) on obese rats by serum metabolomics and gut microbiota analysis. Metabolomics results revealed that abnormal lipid metabolism was formed due to obesity. The supplement of FP and NFP improved the glycerophospholipids, glycosphingolipids, and amino acid metabolism of the obese rats, which alleviated the hypercholesterolemia and overweight in rats. Furthermore, the disorder of gut microbiota was ameliorated by FP and NFP. FP promoted the growth of beneficial bacteria, such as phylum Firmicutes, Actinobacteria, and genera Anaerostipes, Coprococcus, Lactobacillus, and Bifidobacterium. FP also reduced several harmful bacteria belonging to the phylum Proteobacteria and genera Helicobacter. The positive correlation of the weight loss and lowering of serum lipids with the increased beneficial bacteria further elucidated that the anti-obesity effect of FP in obese rats is associated with the regulation of gut microbiota and serum metabolites. The results of this study could provide information for developing probiotic products in the future that may have beneficial effects on the prevention or treatment of obesity.