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

Lipid metabolism regulation by dietary polysaccharides with different structural properties

Lipid metabolism plays an important role in energy homeostasis maintenance in response to stress. Nowadays, hyperlipidemia-related chronic diseases such as obesity, diabetes, atherosclerosis, and fatty liver pose significant health challenges. Dietary polysaccharides (DPs) have gained attention for their effective lipid-lowering properties. This review examines the multifaceted mechanisms that DPs employ to lower lipid levels in subjects with hyperlipidemia. DPs could directly inhibit lipid intake and absorption, promote lipid excretion, and regulate key enzymes involved in lipid metabolism pathways, including triglyceride and cholesterol anabolism and catabolism, fatty acid oxidation, and bile acid synthesis. Additionally, DPs indirectly improve lipid homeostasis by modulating gut microbiota composition and alleviating oxidative stress. Moreover, the lipid-lowering mechanisms of particular structural DPs (including β-glucan, pectin, glucomannan, inulin, arabinoxylan, and fucoidan) are summarized. The relationship between the structure and lipid-lowering activity of DPs is also discussed based on current researches. Finally, potential breakthroughs and future directions in the development of DPs in lipid-lowering activity are discussed. The paper could provide a reference for further exploring the mechanism of DPs for lipid regulations and utilizing DPs as lipid-lowering dietary ingredients.

Subcritical water extraction of polysaccharides from Gastrodiae Rhizoma: optimization, characterization and in vitro hepatoprotective activity

Subcritical water extraction (SWE) is an efficient and eco-friendly technology that rapidly extracts valuable compounds from natural materials. In this study, response surface methodology (RSM) was utilized to determine the optimal extraction conditions for Gastrodiae Rhizoma using SWE (GRP-S). The optimum conditions were found to be 161 °C extraction temperature, 41 min extraction time, and a solid-to-liquid ratio of 1.55 mg/mL. Under these optimal conditions, the experimental yield of GRP-S was 66.32% ± 0.10% (n = 3), demonstrating a significant increase compared to hot water reflux extraction (HWE) in the extraction yield of polysaccharides. Characterization studies employing SEM, FT-IR, and HPAEC-PAD confirmed the differences between GRP-S and GRP-H (GRP obtained by HWE). Furthermore, both GRP-S and GRP-H exhibited a significant ability to protect HepG2 cells from ethanol-induced damage, with GRP-S showcasing a superior effect. The widespread adoption of SWE technology can lead to high GRP content in extracts and promote the green and sustainable development of natural products extraction processes.

Effect of subcritical water temperature on the chain conformation and immune activity of ginger polysaccharides

In this study, the ginger polysaccharides extracted from hot water (HW-G) were modified with subcritical water (SW-G) to effectively regulate their immune activity, and the relationship between polysaccharide chain conformation and immune activity at different subcritical water temperatures was investigated. The results indicated that, compared with HW-G, the xylose and mannose were degraded at high temperatures. The molecular weight of ginger polysaccharide decreased from 1.083 × 106 g/mol to 3.113 × 105 g/mol after subcritical water modification (100-160 °C). The chain conformation transitioned from rigid rod chain to semi-rigid chain and eventually to random coil. The degree of relaxation of the polysaccharide chains showed a continuous increase trend. Additionally, ginger polysaccharide modified by subcritical water at 130 °C was found to promote the proliferation and phagocytosis of 264.7 cells more obviously and signally increase the secretion levels of NO, IL-6, TNF-α and IL-1β. When the subcritical water temperature exceeds 130 °C, the activity of ginger polysaccharide begins to decline rapidly. These findings demonstrate a close correlation between polysaccharide chain conformation and immunomodulatory activity, confirming the feasibility of the subcritical water temperature effect as a means of immune activity regulation, which opens up a new approach to obtaining highly active polysaccharides.

Research progress in the preparation, structural characterization, and biological activities of polysaccharides from traditional Chinese medicine

Traditional Chinese medicines are tremendous sources of polysaccharides, which are of great interest in the human welfare system as natural medicines, food, and cosmetics. This review aims to highlight the recent trends in extraction (conventional and non-conventional), purification and analytic techniques of traditional Chinese medicine polysaccharides (TCMPs), and the chemical structure, biological activities (anti-tumor, hypoglycemic, antioxidant, intestinal flora regulation, immunomodulatory, anti-inflammatory, anti-aging, hypolipidemic, hepatoprotective, and other activities), and the underlying mechanisms of polysaccharides extracted from 76 diverse traditional Chinese medicines were compared and discussed. With this wide coverage, a total of 164 scientific articles were searched from the database including Google Scholar, PubMed, Web of Science, and China Knowledge Network. This comprehensive survey from previous reports indicates that TCMPs are non-toxic, highly biocompatible, and good biodegradability. Besides, this review highlights that TCMPs may be excellent functional factors and effective therapeutic drugs. Finally, the current problems and future research advances of TCMPs are also introduced. New valuable insights for the future researches regarding TCMPs are also proposed in the fields of therapeutic agents and functional foods.

Preparation, characterization and immune response of chitosan‑gold loaded Myricaria germanica polysaccharide

In this study, a novel nano-drug delivery system (CS-Au NPs) based on gold nanoparticles (Au NPs) and chitosan (CS) that modified Myricaria germanica polysaccharide (MGP) was developed to enhance immune responses. At a MGP to CS Au ratio of 5:1, CS-Au-MGP NPs had a loading capacity of 78.27 %. The structure of CS-Au-MGP NPs were characterized by Transmission electron microscope, TEM-energy dispersive spectroscopy mapping, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, particle size and zeta-potential distribution analysis. Under weakly acidic conditions, in vitro CS-Au-MGP NPs release was most effective. In vivo showed that co-immunization with CS-Au-MGP NPs and PCV2 significantly increased the organ index of the thymus, spleen, and liver in mice. Additionally, CS-Au-MGP NPs significantly increased the levels of IgG, IgG1, and IgG2a antibodies, as well as IFN-γ and IL-6 levels. Furthermore, the CS-Au-MGP NPs promoted proliferation of spleen T and B lymphocytes, increased the number of CD3+, CD4+, and CD8+ cells, and increased the CD4+/CD8+ T cell ratio. Meanwhile, CS-Au-MGP NPs remarkably TLR2/IRAK4 pathway activation and mRNA levels of cytokines (IFN-γ and IL-6). These results indicated that CS-Au-MGP NPs could enhance the immune activity, and it could be potentially used as an MGP delivery system for the induction of strong immune responses.

Natural polysaccharides protect against diet-induced obesity by improving lipid metabolism and regulating the immune system

Unhealthy dietary patterns-induced obesity and obesity-related complications pose a great threat to human health all over the world. Accumulating evidence suggests that the pathophysiology of obesity and obesity-associated metabolic disorders is closely associated with dysregulation of lipid and energy metabolism, and metabolic inflammation. In this review, three potential anti-obesity mechanisms of natural polysaccharides are introduced. Firstly, natural polysaccharides protect against diet-induced obesity directly by improving lipid and cholesterol metabolism. Since the immunity also affects lipid and energy metabolism, natural polysaccharides improve lipid and energy metabolism by regulating host immunity. Moreover, diet-induced mitochondrial dysfunction, prolonged endoplasmic reticulum stress, defective autophagy and microbial dysbiosis can disrupt lipid and/or energy metabolism in a direct and/or inflammation-induced manner. Therefore, natural polysaccharides also improve lipid and energy metabolism and suppress inflammation by alleviating mitochondrial dysfunction and endoplasmic reticulum stress, promoting autophagy and regulating gut microbiota composition. Specifically, this review comprehensively summarizes underlying anti-obesity mechanisms of natural polysaccharides and provides a theoretical basis for the development of functional foods. For the first time, this review elucidates anti-obesity mechanisms of natural polysaccharides from the perspectives of their hypolipidemic, energy-regulating and immune-regulating mechanisms.

Gut Microbiota Combined with Serum Metabolomics to Investigate the Hypoglycemic Effect of Actinidia arguta Leaves

Actinidia arguta leaves (AAL) are an excellent source of bioactive components for the food industry and possess many functional properties. However, the hypoglycemic effect and mechanism of AAL remain unclear. The aim of this work was to investigate the potential hypoglycemic effect of AAL and explore its possible mechanism using 16S rRNA sequencing and serum metabolomics in diabetic mice induced by high-fat feeding in combination with streptozotocin injection. A total of 25 flavonoids from AAL were isolated and characterized, and the contents of the extract from the AAL ranged from 0.14 mg/g DW to 8.97 mg/g DW. The compound quercetin (2) had the highest content of 8.97 ± 0.09 mg/g DW, and the compound kaempferol-3-O-(2'-O-D-glucopyl)-β-D-rutinoside (12) had the lowest content of 0.14 ± 0.01 mg/g DW. In vivo experimental studies showed that AAL reduced blood glucose and cholesterol levels, improved insulin sensitivity, and ameliorated oxidative stress and liver and kidney pathological damage. In addition, gut microbiota analysis found that AAL significantly reduced the F/B ratio, enriched the beneficial bacteria Bacteroides and Bifidobacterium, and inhibited the harmful bacteria Lactobacillus and Desulfovibrio, thereby playing an active role in intestinal imbalance. In addition, metabolomics analysis showed that AAL could improve amino acid metabolism and arachidonic acid metabolism, thereby exerting a hypoglycemic effect. This study confirmed that AAL can alleviate type 2 diabetes mellitus (T2DM) by regulating intestinal flora and interfering with related metabolic pathways, providing a scientific basis for its use as a dietary supplement and for further exploration of the mechanism of AAL against T2DM.

Freeze-dried powder of daylily bud improves bromocriptine-induced lactation disorder in rats via JAK2/STAT5 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Milk deficiency is a prevalent problem in the world. Daylily (Hemerocallis citrina Borani), called the Chinese mother flower, is a traditional vegetable and is believed to possess a galactagogue effect in China. Flavonoids and phenols are considered as the active ingredients of daylily to promote lactation and improve depression.

AIM OF THE STUDY

The aim of this study was to investigate the prolactin effects of freeze-dried powder of flower buds of H. citrina Baroni in rat and its action mechanisms.

MATERIALS AND METHODS

The chemical constituents of flower buds of H. citrina Baroni treated by different drying techniques were analyzed by ultrahigh pressure liquid chromatography-mass spectrometry. Sprague-Dawley (SD) rat model induced by bromocriptine was used to evaluate the effect of freeze-dried powder of daylily buds on promoting lactation. Network pharmacology method, ELISA, qPCR, and Western blot were used to clarify the action mechanisms.

RESULTS

We detected 657 compounds in daylily buds. The relative contents of total flavonoids and phenols in freeze-dried samples were higher than those in dried ones. Bromocriptine, as a dopamine receptor agonist, can significantly inhibit prolactin in rats. Daylily buds can restore the levels of prolactin, progesterone and estradiol depressed by bromocriptine, effectively improve the milk production of the rat, and promote the repair of rat mammary gland tissue. We analyzed the relationship between the chemical components of daylily buds and the genes related to lactation with network pharmacology method, revealing that flavonoids and phenols may be the active components that promoted milk production via JAK2/STAT5 pathway, which was confirmed by the results of qPCR and Western blot. Daylily buds can increase the mRNA expression of PRLR, CSN2, LALBA and FASN and the protein expression of PRLR, JAK2 and STAT5.

CONCLUSION

Daylily buds can improve the insufficient lactation of rats induced by bromocriptine through PRLR/JAK2/STAT5 pathway, and the freeze-dried processing method may better retain the active components of flavonoids and phenols that promote milk in daylily.

Study on Anti-Constipation Effects of Hemerocallis citrina Baroni through a Novel Strategy of Network Pharmacology Screening

Daylily (Hemerocallis citrina Baroni) is an edible plant widely distributed worldwide, especially in Asia. It has traditionally been considered a potential anti-constipation vegetable. This study aimed to investigate the anti-constipation effects of daylily from the perspective of gastro-intestinal transit, defecation parameters, short-chain organic acids, gut microbiome, transcriptomes and network pharmacology. The results show that dried daylily (DHC) intake accelerated the defecation frequency of mice, while it did not significantly alter the levels of short-chain organic acids in the cecum. The 16S rRNA sequencing showed that DHC elevated the abundance of Akkermansia, Bifidobacterium and Flavonifractor, while it reduced the level of pathogens (such as Helicobacter and Vibrio). Furthermore, a transcriptomics analysis revealed 736 differentially expressed genes (DEGs) after DHC treatment, which are mainly enriched in the olfactory transduction pathway. The integration of transcriptomes and network pharmacology revealed seven overlapping targets (Alb, Drd2, Igf2, Pon1, Tshr, Mc2r and Nalcn). A qPCR analysis further showed that DHC reduced the expression of Alb, Pon1 and Cnr1 in the colon of constipated mice. Our findings provide a novel insight into the anti-constipation effects of DHC.

Onchidium struma polysaccharides exhibit hypoglycemic activity and modulate the gut microbiota in mice with type 2 diabetes mellitus

Onchidium struma polysaccharides (OsPs) are natural biologically active compounds, and our previous work showed that they can inhibit the activity of α-glucosidase in vitro, showing potential hypoglycemic activity. However, the effects of OsPs on type 2 diabetes mellitus (T2DM) in vivo remain unknown. Thus, the anti-diabetic activity of OsPs was evaluated in the present study in diabetic mice. The results showed that OsPs can significantly ameliorate the features of T2DM in mice by improving the levels of fasting blood glucose (FBG), oral glucose tolerance test (OGTT), and pro-inflammatory factors, and ameliorating insulin resistance. Furthermore, OsPs can significantly improve biochemical indicators, decrease the contents of total cholesterol (TC) and triglyceride (TG), and reduce lipid accumulation in the liver. The possible mechanism of the prevention and treatment of T2DM by OsPs may involve the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT-1) signaling pathway. OsPs can regulate the dysbiosis of gut microbiota and reverse the abundance of Lactobacillus in mice with T2DM. Moreover, OsPs significantly increased the concentration of short-chain fatty acids (SCFAs) in mice with T2DM. Our results indicate that OsPs can be used as a novel food supplement for the prevention and treatment of T2DM.

Pumpkin Polysaccharide Extracted by Subcritical Water: Physicochemical Characterization and Anti-Diabetic Effects in T2DM Rats

SCOPE

This study aims to optimize the extraction of pumpkin polysaccharide by subcritical water, investigates the physicochemical properties and biological activities of pumpkin polysaccharide.

METHODS AND RESULTS

Subcritical water is used to extract pumpkin polysaccharide. The structure and composition of pumpkin polysaccharide are analyzed by infrared spectroscopy, gel filtration chromatography, and high-performance liquid chromatography. The hypoglycemic and hypolipidemic potential of pumpkin polysaccharide aere determined by the physicochemical indexes, pathological, and immunohistochemical analysis in T2DM rats induced by STZ + high-fat diet. The optimal conditions for subcritical water are 1:15, 150°C, and 10 min. Pumpkin polysaccharide has α-configurations and are mainly composed of seven different monosaccharides, and it exhibits good free-radical scavenging ability and inhibition of α-amylase, α-glucosidase, and pancreatic lipase activities. Pumpkin polysaccharide treatment in T2DM rats significantly decreases the concentrations of blood glucose, insulin, TC, TG, LDL-C, and MDA; increases the levels of HDL-C; and enhances the antioxidant enzymes activities (SOD and CAT). Histopathology and immunohistochemical analyses reveal that pumpkin polysaccharide has protective effects on kidney and pancreatic organs in T2DM rats.

CONCLUSION

Pumpkin polysaccharide extracted by SWE shows great potential as functional food ingredients and candidates for T2DM treatment.

Hypoglycemic activity in vitro and vivo of a water-soluble polysaccharide from Astragalus membranaceus

The polysaccharide AMP as one main bioactive component of Astragalus membranaceus (Fisch.) Bunge was separated and characterized. The results showed that AMP was a typical acidic heteropolysaccharide dominated by glucose, galacturonic acid and arabinose with typical shear-thinning and fluid-like behavior. Scanning electron microscopy images showed that AMP existed in the state of lamellar aggregates with a smooth compact surface. In addition, AMP exhibited strong antioxidant activity with an oxygen radical absorption capacity value of 278.68 ± 9.31 μM TE per g, and excellent α-glucosidase inhibitory activity and cholate binding ability. Furthermore, in vivo, AMP treatment significantly decreased blood glucose and serum insulin levels, improved glucose intolerance and insulin resistance, regulated the blood lipid profile, alleviated oxidative stress, and relieved liver damage in type 2 diabetes mellitus (T2DM) mice. Pearson correlation analysis suggested that the mitigation of oxidative stress contributed to the hypoglycemic effect of AMP, indicating that it is a beneficial functional food ingredient for T2DM.

Systematic evaluation on the physicochemical characteristics of a series polysaccharides extracted from different edible lilies by ultrasound and subcritical water

A series polysaccharide samples extracted from three edible lilies (Lilium davidii var. willmottiae, Lilium brownii var. viridulum, and Lilium lancifolium) by subcritical water and ultrasound-assisted extraction were systematically compared. The results showed that extraction method was a more important factor than lily species. Subcritical water extracted lily polysaccharides (S-LP) with higher yield, molecular weight, neutral glucose and uronic acid content as well as apparent viscosity. Ultrasound-assisted extracted lily polysaccharides (U-LP) with higher reducing sugars and protein content. Moreover, due to the degradation of glycosidic bonds, ultrasonic extraction was easier to obtain lower molecular weight polysaccharides. In addition, the extraction method significantly affected the monosaccharide proportion of polysaccharides, but had no effect on type. Glucose was the main component in S-LP, and glucose and mannose were the main components in U-LP. The micromorphology of different polysaccharide samples was similar, and the scanning electron microscope (SEM) images showed regular/irregular particle clusters with different particle sizes. Overall, the relationships between extraction methods, lily species and polysaccharide properties were preliminarily elucidated, providing a reference for the targeted extraction of specific lily polysaccharides (LP).

Polysaccharide from Hemerocallis citrina Borani by subcritical water with different temperatures and investigation of its physicochemical properties and antioxidant activity

Hemerocallis citrina Borani as a low-cost vegetable, has various health benefits. However, the industry of H. citrina Borani is in the state of primary processing, with poor economic benefits. This study aimed to investigate the physicochemical properties, and the antioxidant activity of H. citrina Borani polysaccharide (HCBP) using subcritical water extraction (SWE) at different temperatures, to expand the value of H. citrina Borani. HCBP mainly composed of nine monosaccharides (glucose, galactose, rhamnose, fucose, mannose, arabinose, xylose, galacturonic acid, and glucuronic acid), among which the content of neutral sugar was higher and uronic acid was lower. HCBP contained glycosidic bond of β-configurations and trace quantities protein. The molecular weight of HCBP decreased with increasing temperature. Shear thinning occurred in HCBP with the increase of shear rate (0.01-1 s^-1), and the apparent viscosity of HCBP decreased at higher temperature (150-160°C) with the increase continuously of shear rate (1-10 s^-1), but almost remained constant at lower temperature (130-140°C). Scanning electron microscope showed that HCBP had rough surface, loose structure, obvious particle gap, and irregular shape. In addition, HCBP extracted at 160°C had strong FRAP activity, and HCBP extracted at 130 and 140°C had better ABTS radical scavenging activity. This study suggests that HCBP extracted by SWE could provide a cheap raw material as food thickening agent and natural antioxidants.