Structural characterization of a homopolysaccharide with hypoglycemic activity from the roots of Pueraria lobata

The isolation, characterization and biological activities of the non-glucan polysaccharides from the high-starch-content plant Pueraria mirifica

The dried root of Pueraria mirifica (P. mirifica) is an edible foodstuff widely used in Asian countries. P. mirifica is known for its high starch content. The isolation of polysaccharides from high-starch plant parts is challenging due to the interference of starch. Therefore, this study aimed to develop a technique for isolating and investigating the structure and activity of non-glucan polysaccharides from P. mirifica (PMP). An effective starch removal process was developed using α-amylase hydrolysis and thorough membrane dialysis. Four non-glucan polysaccharides were isolated, and PMP-2 was subjected to structural elucidation. The results indicated that PMP-2 has a molecular weight of 124.4 kDa and that arabinose and galactose are the main components, accounting for 27.8 % and 58.5 %, respectively. Methylation and NMR analysis suggested that PMP-2 is an Arabinogalactan composed of 1,6-linked Galp and 1,4-linked Galp as the main chain, with arabinan and rhamnose as side chains. Furthermore, PMP-C and PMP-2 exhibited concentration-dependent antioxidant activities against DPPH, ABTS, and hydroxyl radicals and certain immunomodulatory activities related to the release of NO, TNF-α and IL-6. These findings suggest that PMP-2 has potential therapeutically active ingredient in functional foods. The developed method successfully removed starch and isolated non-glucan polysaccharides from the high-starch content plant P. mirifica and can be applied to other high-starch plants.

Recent advances in medicinal and edible homologous plant polysaccharides: Preparation, structure and prevention and treatment of diabetes

Medicinal and edible homologs (MEHs) can be used in medicine and food. The National Health Commission announced that a total of 103 kinds of medicinal and edible homologous plants (MEHPs) would be available by were available in 2023. Diabetes mellitus (DM) has become the third most common chronic metabolic disease that seriously threatens human health worldwide. Polysaccharides, the main component isolated from MEHPs, have significant antidiabetic effects with few side effects. Based on a literature search, this paper summarizes the preparation methods, structural characterization, and antidiabetic functions and mechanisms of MEHPs polysaccharides (MEHPPs). Specifically, MEHPPs mainly regulate PI3K/Akt, AMPK, cAMP/PKA, Nrf2/Keap1, NF-κB, MAPK and other signaling pathways to promote insulin secretion and release, improve glycolipid metabolism, inhibit the inflammatory response, decrease oxidative stress and regulate intestinal flora. Among them, 16 kinds of MEHPPs were found to have obvious anti-diabetic effects. This article reviews the prevention and treatment of diabetes and its complications by MEHPPs and provides a basis for the development of safe and effective MEHPP-derived health products and new drugs to prevent and treat diabetes.

Extraction, structural-activity relationships, bioactivities, and application prospects of Pueraria lobata polysaccharides as ingredients for functional products: A review

Pueraria lobata (Willd.) Ohwi is an important resource with dual functions in medicine and food since ancient times. Polysaccharides are the main bioactive component of P. lobata and have various bioactivities, such as antidiabetic, antioxidant, immunological activities, etc. Due to the distinctive bioactivity of P. lobata polysaccharides (PLPs), the research on PLPs is booming. Although a series of PLPs have been isolated and characterized, the chemical structure and mechanism are unclear and need further study. Here, we reviewed recent progress in isolation, identification, pharmacological properties, and possible therapeutic mechanisms of PLPs to update awareness of these value-added natural polysaccharides. Besides, the structure-activity relationships, application status, and toxic effects of PLPs are highlighted and discussed to afford a deeper understanding of PLPs. This article may provide theoretical insights and technical guidance for developing PLPs as novel functional foods.

An Acidic Heteropolysaccharide Isolated from Pueraria lobata and Its Bioactivities

A novel water-soluble acidic heteropolysaccharide, called PPL-1, was purified from Pueraria lobata. PPL-1 had an average molecular weight of 35 Kad, and it was composed of glucose, arabinose, galactose and galacturonic acid (6.3:0.8:0.8:2.1). In accordance with methylation and nuclear magnetic resonance analyses, PPL-1 primarily consisted of (1→2)-linked α-Araf, (1→4)-linked α-Glcp, (1→)-linked β-Glcp, (1→6)-linked α-Glcp, (1→3,6)-linked α-Galp, (1→)-linked β-GalpA and (1→4)-linked α-GalpA. In terms of bioactivities, PPL-1 exhibited remarkable scavenging ability towards DPPH (1,1-Diphenyl-2-picrylhydrazyl) radicals and moderate activity by enhancing the proliferation rate of RAW 264.7 cells by approximately 30% along with the secretion of NO. This work demonstrates that PPL-1 can be a potential source of immunoenhancers and antioxidants.

Structure of a Pueraria root polysaccharide and its immunoregulatory activity on T and B lymphocytes, macrophages, and immunosuppressive mice

In this experiment, the polysaccharide was extracted from Pueraria lobata (Willd.) Ohwi, and its structural characteristics and bioactivity were investigated. The results showed that Pueraria lobata polysaccharide (PLP) was composed of fucose, arabinose, galactose, glucose, xylose, mannose in a molar proportion of 0.09:1.25:2.19:95.74:0.43:0.30 with a number molar masses (Mn) weight of 14.463 kDa. Besides, FT-IR, Methylation, and NMR analysis revealed that PLP were mainly composed of the main chain →4)-α-Glcp (1→ and →4,6)-α-Glcp (1→, and the branched chain α-Glcp (1→. In vitro experiment, the results showed that PLP could stimulate the expression of surface molecules on RAW264.7 and (T and B) lymphocytes proliferation, simultaneously to stimulate their cytokines secretion. In vivo experiment, the immune organ index, cytokine content, and T lymphocyte subtype in cyclophosphamide-induced immunosuppressed mice could be improved by PLP. These data proved that PLP could be used as a useful immunomodulator to enhance the immune activity of RAW264.7, T, and B cells and improve the immune function of cyclophosphamide-treated mice.

Effects of 6-Shogaol on Glucose Uptake and Intestinal Barrier Integrity in Caco-2 Cells

As the main bioactive component in dried ginger, 6-shogaol has potential hypoglycemic activity, but its mechanism is still unclear. The process of carbohydrate digestion and glucose absorption is closely related to the enzymatic activity of epithelial brush cells, expression of glucose transporters, and permeability of intestinal epithelial cells. Therefore, this study explored the hypoglycemic mechanism of 6-shogaol from the perspective of glucose uptake, absorption transport, and protection of intestinal barrier function. Based on molecular docking, the binding energy of 6-shogaol and α-glucosidase is -6.24 kcal/mol, showing a high binding affinity. Moreover, a-glucosidase enzymatic activity was reduced (-78.96%) when the 6-shogaol concentration was 500 µg/mL. After 6-shogaol intervention, the glucose uptake was reduced; the relative expression of glucose transporters GLUT2 and SGLT1 were down regulated; and tight junction proteins ZO-1, Occludin and Claudin were up regulated in differentiated Caco-2 cells. This study confirmed that 6-shogaol effectively inhibits the activity of α-glucosidase and has beneficial effects on glucose uptake, protection of intestinal barrier function, and promotion of intestinal material absorption.

α-D-1,3-glucan from Radix Puerariae thomsonii improves NAFLD by regulating the intestinal flora and metabolites

Radix Puerariae thomsonii, the root of the botanical family Fabaceae species Pueraria montana var. thomsonii (Benth.) MR Almeida, can be used as food or medicine. Polysaccharides are important active constituents of this root. A low molecular weight polysaccharide, RPP-2 having α-D-1,3-glucan as the main chain, was isolated and purified. RPP-2 could promote the growth of probiotics in-vitro. Therefore, the effects of RPP-2 on a high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) C57/BL6J mouse models were investigated. RPP-2 could reduce HFD-induced liver injury by reducing inflammation, glucose metabolism, and steatosis, thereby improving NAFLD. RPP-2 regulated the abundances of intestinal floral genera Flintibacter, Butyricicoccus, and Oscillibacter, and their metabolites Lipopolysaccharide (LPS), bile acids, and short-chain fatty acids (SCFAs), thereby improving inflammation, lipid metabolism, and energy metabolism signaling pathways. These results confirmed that RPP-2 play a prebiotic role by regulating intestinal flora and microbial metabolites, playing a multi-pathway and multi-target role in improving NAFLD.

San Pian decoction can treat nitroglycerin-induced migraine in rats by inhibiting the PI3K/AKT and MAPK signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

San Pian decoction (SPD), a traditional Chinese medicine preparation composed of eight herbs, has been reported to alleviate migraine. However, its active ingredients and the potential mechanism of action remains unclear. The purpose of this study was to comprehensively analyze SPD for the treatment of chronic migraine based on pharmacological direction and to identify the active ingredients and pharmacological mechanism of SPD in the treatment of migraine.

MATERIALS AND METHODS

The active components in SPD were identified by AB SCIEX quadrupole time-of-flight mass spectrometer, and the prediction targets and pharmacological networks related to migraine were constructed. The mechanism of SPD in treating migraine was studied through network pharmacology, which was further verified using pharmacological experiments.

RESULTS

A total of 489 targets of 26 compounds were identified. Based on Venn analysis, we found 117 intersection targets between SPD and migraine, that is, these targets were related to the treatment of migraine. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that the treatment of migraine using SPD was related to the PI3K/AKT and MAPK signaling pathways. The effect of SPD on migraine was verified by measuring the levels of the inflammatory factors, nitric oxide (NO), interleukin (IL-6), endothelin (ET),5-hydroxytryptamine(5-HT), indoleamine 2,3-dioxygenas (IDO), tumor necrosis factor (TNF-α) and calcitonin gene-related peptide (CGRP). Lastly, real-time polymerase chain reaction and western blotting were used to verify gene and protein expression in the PI3K/AKT and MAPK signaling pathways. Expression of the genes P38, JNK, ERK, PI3K and AKT, and the protein expression of p-P38, p-JNK, p-ERK, p-AKT and p-PI3K were significantly downregulated. Our findings indicated that SPD could prevent inflammation by regulating the inflammatory cytokines and key genes and proteins in the PI3K/AKT and MAPK signaling pathways to treat migraine.

CONCLUSION

Our findings reveal that SPD could treat nitroglycerin-induced migraine by regulating p-AKT, p-pI3k, p-p38, p-ERK, p-JNK, IL-6, and TNF-α inflammatory factors in the PI3K/AKT and MAPK signaling pathways.

Assessment of Novel Oligopeptides from Rapeseed Napin (Brassica napus) in Protecting HepG2 Cells from Insulin Resistance and Oxidative Stress

Oligopeptides (Thr-His-Leu-Pro-Lys (THLPK), His-Pro-Leu-Lys (HPLK), Leu-Pro-Lys (LPK), His-Leu-Lys (HLK), and Leu-His-Lys (LHK)) are newly identified from rapeseed napin (Brassica napus) protein-derived hydrolysates with the capability of upregulating glucose transporter-4 (GLUT4) expression and translocation. However, whether each of them enhances GLUT4 expression and translocation and their specific mechanisms remain unclear. Here, we assess the effects of the oligopeptides against insulin resistance (IR) and oxidative stress in hepatocytes and screen out the most antidiabetic one. Specifically, compared with other oligopeptides, LPK not only remarkably elevated glucose consumption to 8.45 mmol/L protein; superoxide dismutase (SOD) activity to 319 U/mg protein; GLUT4 expression and translocation; and phosphorylated level of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (Akt) (P < 0.05) but also remarkably attenuated the reactive oxygen species (ROS) level to 2255, lactate dehydrogenase (LDH) activity to 20.5 U/mg protein, malondialdehyde (MDA) content to 241 nmol/mg protein, and NO content to 1302 μmol/mL protein (P < 0.05). These findings demonstrated that antidiabetic oligopeptide LPK possessed the most potential to protect HepG2 cells from IR and oxidative stress via activating IRS-1/PI3K/Akt/GLUT4 and regulating common oxidative markers in vitro.

Efficacy and Mechanism of Pueraria lobata and Pueraria thomsonii Polysaccharides in the Treatment of Type 2 Diabetes

Diabetes is called a “wasting and thirsting disorder” in Chinese traditional medicine because there is a depletion of vital substances in the body independent of the intake of food or water and an inability to reintroduce fluids through drinking. Pueraria lobata (Willd.) Ohwi (GG) and Pueraria thomsonii Benth. (FG) are traditional Chinese herbal medicines used in the treatment of wasting-thirst that reduce blood glucose levels. Flavonoids are the main pharmacodynamic components of GG and FG, and they are also the most studied components at present, but polysaccharides are also active components of GG and FG, which, however, are less studied. Therefore, this study aimed to investigate the effect of Pueraria polysaccharides (GG and FG polysaccharides) on type 2 diabetes (T2D), as well as their related mechanisms of action in terms of both intestinal flora and metabolomics. The C57BL/KsJ-db/db mouse model, a well-established model of obesity-induced T2D, was used in this study. The metabolomic analysis showed that Pueraria polysaccharides improved the metabolic profile of diabetic mice and significantly regulated metabolites and metabolic pathways. Both GG and FG polysaccharides regulated insulin resistance in mice by regulating PPAR signaling pathway so as to treat T2D. Additionally, Pueraria polysaccharides regulated the structure of gut microbiota and improved the diabetes-related metabolic pathway. Therefore, this study discovered the antidiabetic effects and potential mechanisms of Pueraria polysaccharides through multiple pathways involving gut microbiota and metabolites, providing a theoretical basis for further studies on their effects in the treatment of T2D.

A diarylheptanoid compound from Alpinia officinarum Hance ameliorates high glucose-induced insulin resistance by regulating PI3K/AKT-Nrf2-GSK3β signaling pathways in HepG2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Alpinia officinarum Hance, a perennial natural medicine-food herb, has been traditionally used to treat colds, stomachache, and diabetes for thousands of years. 1,7-Diphenyl-4E-en-3-heptanone (DPH5), a diarylheptanoid isolated from the rhizome of A. officinarum has been reported to be safe and to have antioxidant and hypoglycemic effects, suggesting its potential in the treatment of insulin resistance (IR).

AIM OF THE STUDY

Aim of to investigate the protective effect of DPH5 on IR and elucidate its underlying mechanism of action.

MATERIALS AND METHODS

HepG2 cells were used as the research objects. Glucose uptake and reactive oxygen species (ROS) levels in high glucose-induced insulin-resistant HepG2 cells were assessed using flow cytometry. Glucose consumption and the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were analyzed using the corresponding assay kits. The expression of mRNA and proteins related to insulin signaling, glucose metabolism, and antioxidant factor, including insulin receptor substrate-1 (IRS1), phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), translocation of glucose transporter-4, glycogen synthase kinase-3β (GSK3β), glucokinase (GCK), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), nuclear factor-erythroid 2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NADPH quinoneoxidoreductase (NQO1), and glutathione peroxidase (GSH-Px) was determined using real-time quantitative polymerase chain reaction and western blotting. Furthermore, molecular docking was performed to determine the spatial mechanism of DPH5 on the key targets PI3K, AKT, Nrf2, and GSK3β.

RESULTS

DPH5 could improve IR that manifested as increased glucose uptake and glucose consumption in insulin-resistant HepG2 cells. Moreover, DPH5 could enhance antioxidant capacity by activating Nrf2/HO-1 elements, including increasing Nrf2, HO-1, SOD, NQO1, and GSH-Px expression and reducing MDA, ROS, and JNK levels, thereby improving oxidative stress and ultimately alleviating IR. Additionally, DPH5 could promote the expression of IRS1, PI3K, AKT, GSK3β, GCK, and PK, and downregulate the expression of PEPCK and G6pase, thereby accelerating glucose utilization and enhancing insulin sensitivity. The mechanism underlying the effect of DPH5 in alleviating IR was related to the PI3K/AKT- and Nrf2/HO-1-mediated regulation of the GSK3β signaling pathway, and the results were further confirmed using the specific inhibitors LY294002 and ML385. Results from molecular docking indicated that there were different regulatory sites and interacting forces between DPH5 and PI3K, AKT, Nrf2, and GSK3β; however, the binding force was relatively strong.

CONCLUSIONS

DPH5 improved oxidative stress and glucose metabolism via modulating the PI3K/AKT-Nrf2-GSK3β pathway, thereby ameliorating IR. Overall, our findings suggest the potential of DPH5 as a natural medicine to treat type-2 diabetes mellitus.

Extraction, purification, structure, modification, and biological activity of traditional Chinese medicine polysaccharides: A review

Traditional Chinese medicines (TCM), as the unique natural resource, are rich in polysaccharides, polyphenols, proteins, amino acid, fats, vitamins, and other components. Hence, TCM have high medical and nutritional values. Polysaccharides are one of the most important active components in TCM. Growing reports have indicated that TCM polysaccharides (TCMPs) have various biological activities, such as antioxidant, anti-aging, immunomodulatory, hypoglycemic, hypolipidemic, anti-tumor, anti-inflammatory, and other activities. Hence, the research progresses and future prospects of TCMPs must be systematically reviewed to promote their better understanding. The aim of this review is to provide comprehensive and systematic recombinant information on the extraction, purification, structure, chemical modification, biological activities, and potential mechanism of TCMPs to support their therapeutic effects and health functions. The findings provide new valuable insights and theoretical basis for future research and development of TCMPs.

Daphnetin, a Coumarin in Genus Stellera Chamaejasme Linn: Chemistry, Bioactivity and Therapeutic Potential

Coumarins is a huge family of phenolic compounds containing a common structure of 2 H -1-benzopyran-2-one. Nowadays, more than 1,300 natural-based coumarins have been identified in a variety of plants, bacteria and fungi, many of them exhibited promising biomedical performance. Daphnetin (7,8-dihydroxycoumarin) is a typical coumarin associated with a couple of bioactivities such as anti-cancer, antibacterial, anti-inflammatory and anti-arthritis. In the treatment of diseases, it has been verified that daphnetin has outstanding therapeutic effects on diabetes, arthritis, transplant rejection, cancer and even on central nervous system diseases. Herein, we summarized the chemical synthetic methodologies, bioactivities, therapeutic potentials and structure-activity relationships of daphnetin and its derivatives. Hopefully, this review would be beneficial for the discovery of new coumarin-based biomedicine in the near future.

Isolation, purification and characterization of Pueraria lobata polysaccharide and its effects on intestinal function in cyclophosphamide-treated mice

This study investigated the structure of acidic Pueraria lobata polysaccharide (a-PLP) and its bioactive effects on intestinal function in cyclophosphamide (CY)-treated mice. The structure of a-PLP was preliminarily analyzed, and the results showed that it is composed of fucose, arabinose, rhamnose, galactose, glucose, xylose, mannose, galacturonic acid, and glucuronic acid in a molar proportion of 2.54:16.52: 6.14: 16.60: 4.05: 4.75: 0.48: 47.44: 1.47 with a weight average molecular weight of 22.675 kDa. In addition, the methylation analysis suggested that 4-Gal(p)-UA may be the main backbone of a-PLP. Furthermore, a-PLP (1.2 g/kg, 0.8 g/kg, and 0.4 g/kg) was administered orally for the treatment of CY-treated mice. The results showed that a-PLP could remarkably relieved weight loss and intestinal villous atrophy in CY-treated mice. Meanwhile, the secretion levels of sIgA, β-defensin, cytokines, Mucin-2, and tight junction proteins increased significantly. Moreover, the ratio of T (CD4⁺ and CD8⁺) cells in the Peyer's patches and mesenteric lymph nodes also increased remarkably, along with the number of goblet cells. Furthermore, a-PLP decreased the levels of diamino oxidase and malondialdehyde, but up-regulated the activity of superoxide dismutase. In summary, a-PLP exhibited great benefits by attenuating CY side effects, opening a potential avenue to effectively treat cancer and reduce the suffering of chemotherapy patients.

Radix Puerariae thomsonii polysaccharide (RPP) improves inflammation and lipid peroxidation in alcohol and high-fat diet mice by regulating gut microbiota

Polysaccharides are the important active constituents of Radix Puerariae thomsonii. Numerous studies have shown that polysaccharides can regulate gut microbiota, repair intestinal barrier, and affect the microbiota-intestine-liver axis, thereby showing therapeutic effects on metabolic disorders. In this study, Radix Puerariae thomsonii polysaccharide (RPP) was extracted from Radix Puerariae thomsonii. The average Mw of RPP was determined to be 1.09 × 10⁵ Da and the monosaccharide composition showed it consisted of glucose. The effects and underlying mechanisms of RPP on fatty liver were studied using C57/BL6J mice induced by alcohol and high-fat diet. The results showed that the oral supplementation of RPP could alleviate alcohol and high-fat diet-induced hepatic injury and steatosis. RPP also promoted intestinal barrier integrity and reduced inflammation through NF-κB signaling pathway. RPP could ameliorate the lipid peroxidation by AMPK/NADPH oxidase signaling pathway. Additionally, these improvements might be related to the enrichment of intestinal bacteria Parabacteroides (promote intestinal barrier integrity) and Prevotellaceae UCG 001 (activation of AMPK signaling pathway). These results demonstrated that RPP could improve inflammation and lipid peroxidation in the alcohol and high-fat diet mouse by restoring the intestinal barrier integrity and regulating the gut microbiota. This suggested that RPP was a potential food supplement for the treatment of fatty liver disease.

Modulatory effects of polysaccharides from plants, marine algae and edible mushrooms on gut microbiota and related health benefits: A review

Naturally occurring carbohydrate polymers containing non-starch polysaccharides (NPs) are a class of biomacromolecules isolated from plants, marine algae, and edible mushrooms, and their biological activities has shown potential uses in the prevention and treatment of human diseases. Importantly, NPs serve as prebiotics to provide health benefits to the host through stimulating the proliferation of beneficial gut microbiota (GM) and enhancing the production of short-chain fatty acids (SCFAs). The composition and diversity of GM play a critical role in regulating host health and have been extensively studied in recent years. In this review, the extraction, isolation, purification, and structural characterization of NPs derived from plants, marine algae, and edible mushrooms are outlined. Importantly, the degradation and metabolism of these NPs in the intestinal tract, the effects of NPs on the microbial community and SCFAs generation, and the beneficial effects of NPs on host health by modulating GM are systematically highlighted. Overall, we hope that this review can provide some theoretical references and a new perspective for applications of NPs as prebiotics in functional food and drug development.

Structural characterization, anti-inflammatory and glycosidase inhibitory activities of two new polysaccharides from the root of Pueraria lobata

Diabetes seriously endangers public health and brings a heavy economic burden to the country. Inflammation is one of the main inducing factors of type-2 diabetes (T2D) and may cause some complications of diabetes, such as diabetic encephalopathy and peripheral neuropathy. In-depth research and development of drugs to cure diabetes and complications are of great significance. Pueraria lobate is a medicinal herb used in several countries to treat many diseases. Here, two new polysaccharides (PLB-1-1 and PLB-1-2) were isolated and purified from the root of Pueraria lobata with molecular weights of 9.1 × 10³ Da and 3.8 × 10³ Da, respectively. The structure was evaluated by monosaccharide composition, GC-MS and NMR spectroscopy. It was determined that PLB-1-1 comprised →4)-α-d-Glcp-(1→, α-d-Glcp-(1→, →6)-β-d-Galp-(1→, →3)-α-l-Araf-(1→, →3,6)-β-d-Manp-(1→ and →4,6)-β-d-Manp-(1→, and PLB-1-2 consisted of →4)-α-d-Glcp-(1→, β-d-Glcp-(1→, →4,6)-β-d-Glcp-(1→, →3,6)-β-d-Manp-(1→ and α-l-Fucp-(1→. Furthermore, both PLB-1-1 and PLB-1-2 showed anti-inflammatory and inhibitory activities of α-glucosidase and α-amylase in vitro. Therefore, the new polysaccharides, i.e., PLB-1-1 and PLB-1-2, may be considered candidates for the treatment of diabetes and its related complications.

Through the extraction, isolation and purification of Pueraria lobata, we identified two new polysaccharides with molecular weights of 9.1 × 10³ Da and 3.8 × 10³ Da, and found that they have excellent anti-inflammatory and glycosidase inhibitory effects.

Metabolic Profiling of Carbonyl Compounds for Unveiling Protective Mechanisms of Pueraria lobata against Diabetic Nephropathy by UPLC-Q-Orbitrap HRMS/MS Analysis

Carbonyl compounds play a critical role in the pathogenesis of diabetic nephropathy (DN). Pueraria lobata (PL), also known as "Kudzu", is a widely consumed functional food or nutraceutical and has shown promise in the prevention of diabetes and complications such as DN. To explore the beneficial effects and the underlying mechanisms of PL against DN, a new strategy for in-depth metabolic profiling of carbonyl compounds in DN mice plasma by chemical derivatization combined with UPLC-Q-Orbitrap high-resolution mass spectrometry (HRMS)/MS analysis was developed for the first time. Pharmacological evaluation revealed that PL extracts containing a total of 73 identified compounds could ameliorate kidney injury and regulate abnormal glycolipid metabolism. In metabolomics analysis, 19 carbonyl compounds with significant differences were identified between DN mice and normal mice. Moreover, 12 metabolites had a tendency to return to normal levels after PL treatment. Overall, PL exerts beneficial effects on DN by regulating abnormal glycolipid metabolism and carbonyl stress, and endogenous carbonyl compounds might serve as potential biomarkers for DN.

Based on Plasma Metabonomics and Network Pharmacology Exploring the Therapeutic Mechanism of Gynura procumbens on Type 2 Diabetes

Gynura procumbens (GP) is a perennial herbal medicine and food homologous plant, which has been reported to have a good hypoglycemic effect. However, its active components and underlying mechanism of action are not clear. Here, we aimed to confirm the effects of GP on type 2 diabetes (T2DM) from several different aspects. We used UPLC/Q-TOF MS to analyze the metabolic patterns, which included blood samples of clinical subjects and db/db mice to screen for serum metabolic markers and metabolic pathways. We also used network pharmacology to study GP targets in the treatment of T2DM. Data from endogenous metabolites in plasma showed that two common pathways, including glycerol phosphate metabolism and retinol metabolism, were identified in plasma samples of the groups. Finally, Western blot analysis was used to verify the expression of proteins in the PI3K/AKT and AGE–RAGE signaling pathways. The protein expression of AKT, eNOS, iNS, and MAPK was significantly upregulated, and the expression of caspase-8 and caspase-3 was significantly downregulated. Thus, our findings indicated that GP could alleviate insulin resistance by regulating biometabolic markers and key proteins in the PI3K/AKT and AGE–RAGE signaling pathways to treat T2DM.

Effect of Sleeve Gastrectomy on Glycometabolism via Forkhead Box O1 (FoxO1)/Lipocalin-2 (LCN2) Pathway

BACKGROUND The mechanism by which sleeve gastrectomy (SG) improves glycometabolism has remained unclear so far. Increasing evidence has demonstrated that bone is a regulator of glucose metabolism, and osteoblast-derived forkhead box O1 (FoxO1) and lipocalin-2 (LCN2) are regulators of energy metabolism. The aim of this study was to investigate whether the FOXO1/LCN2 signaling pathway is involved in the anti-diabetic effect of SG. MATERIAL AND METHODS Insulin resistance was induced in Wistar rats, which were then intraperitoneally injected with streptozotocin to induce a type 2 diabetic state. Levels of fasting blood glucose, serum insulin, HbA1c, and LCN2 were analyzed at corresponding time points after SG and sham surgeries. The expressions of FOXO1, LCN2, and the melanocortin 4 receptor (MC4R) in bone and hypothalamus were detected by immunofluorescence. FOXO1 siRNA was applied to downregulate FOXO1 expression in osteoblasts of rats. The influence of FOXO1 gene on expression of LCN2 was investigated in cultured osteoblasts by western blot and PCR. RESULTS Glucose metabolism in the SG group was significantly improved. The LCN2 expression in bone in the SG group was higher than that in the sham group, whereas FOXO1 expression in the SG group was lower than that in the sham group. The binding rate of LCN2 and MC4R in the hypothalamus was also higher in the SG group compared with that in the sham group. The downregulation of FOXO1 expression in osteoblasts was accompanied by upregulation of LCN2 expression. CONCLUSIONS These results suggest that the FOXO1/LCN2 signaling pathway participates in the anti-diabetic effect of SG.