Structural Characterization and Hypoglycemic Activity of a Novel Pumpkin Peel Polysaccharide-Chromium(III) Complex

From structure to function: Stellariae Radix polysaccharides as innovative edible coatings with antioxidant and hypoglycemic properties

Stellariae Radix Polysaccharides (SRP, extracted from roots of Stellaria dichotoma var. lanceolata Bge.) was structurally characterized and its potential as both a fruit preservation agent and a hypoglycemic bioactive compound was explored. SRP, containing 73.23 ± 1.02 % total sugar, was separated into two main fractions, SRP-1 (neutral) and SRP-2 (acidic), using DEAE-52 cellulose chromatography, with respective yields of 74.07 ± 0.90 % and 2.93 ± 0.12 %. SRP and its fractions were then analyzed in detail by GPC, HPLC, FT-IR, and NMR, which revealed their key structural features and bioactive potential. In vitro assays indicated SRP has high antioxidant capacity, with DPPH• and ABTS•+ scavenging activities of 70.43 ± 0.09 % and 96.82 ± 0.05 % at 8 mg/mL, respectively. SRP inhibited α-glucosidase (88.60 ± 1.84 %) and α-amylase (75.76 ± 1.74 %) in a dose-dependent manner, underscoring its hypoglycemic properties. Applied as an edible coating for fresh-cut apple, SRP enhanced preservation, reduced weight loss, maintained firmness, and conserved ascorbic acid over 96 h. It also limited malondialdehyde production, reduced electrolyte leakage, protected cell membrane integrity, and mitigated oxidative damage. These findings position SRP as a novel, multifunctional component in food preservation technologies that align with both environmental sustainability and diabetic dietary needs.

Steam explosion improved the physicochemical properties, hypoglycemic effects of polysaccharides from Clerodendranthus spicatus leaf via regulating IRS1/PI3K/AKT/GSK-3β signaling pathway in IR-HepG2 cells

Clerodendranthus spicatus (C. spicatus) leaf is a kind of functional tea and traditional Chinese folk medicine and it is famous for hypoglycemic value. The effects of steam explosion (SE) pretreatment on structural characteristics, α-glucosidase inhibition activity and hypoglycemic effects of C. spicatus leaf polysaccharides (CSP) were investigated. Two polysaccharides fractions from the untreated C. spicatus leaf (NTCSP-A) and SE treated C. spicatus leaf (SECSP-C) were obtained after the purification by DEAE Sepharose Fast Flow column chromatography. Results showed that SE pretreatment obviously increased the yields of CSP from 10.17 % to 13.43 % and decreased the molecular weight distribution. Monosaccharide composition analysis indicated that the main compositional modification by SE pretreatment was the increase in the proportion of mannose, glucuronic acid and arabinose. And SE pretreatment changed the inhibition type against α-glucosidase from competitive inhibition (NTCSP-A) to uncompetitive inhibition (SECSP-C). In addition, SE pretreatment increased the anti-diabetic activity on IR-HepG2 cells by increasing the glucose consumption and glycogen synthesis and regulating IRS1/PI3K/AKT/GSK-3β signaling pathway. This study indicated that SE technology modified the physiochemical properties and increased the hypoglycemic activity of CSP. It also provided helpful information on the application of SE in the efficient preparation and utilization of bioactive polysaccharides.

Structural characteristics and hypoglycemic activity of a polysaccharide from an edible bolete Phlebopus portentosus

Phlebopus portentosus, a bolete renowned for its exceptional flavor, delightful taste, and pleasant texture, has been reported to exhibit hypoglycemic activity attributed to its polysaccharides. However, the structural characteristics of these polysaccharides and the mechanisms of action remain unclear. In this study, a neutral polysaccharide (PPP-0A) was isolated and purified from its fruiting bodies using DEAE-52 cellulose and Sephacryl S-400 HR propylene dextran gel column chromatography. The structural characteristics of PPP-0A were elucidated at multiple levels, employing SEC-MALLS-RI, GC-MS, IR, methylation analysis, NMR, SEM, and CD. PPP-0A is identified as an α-pyranoside with a molecular weight of 13.2 kDa, comprising galactose, fucose, glucose, mannose, and xylose in the ratios of 62.26:16.96:15.23:4.68:0.87. Methylation and NMR analyses suggest that the backbone of PPP-0A mainly consists of →6)-α-D-Galp-(1→, →2,6)-α-D-Galp-(1→, and →3)-α-D-Glcp-(1→. The branches are formed by α-L-Fucp-(1→ linked to the sugar residue at the O-2 position of →2,6)-α-D-Galp-(1→. Furthermore, we confirmed the potent hypoglycemic activity of PPP-0A through enzyme activity assays, inhibition kinetics, and in vitro insulin resistance experiments using HepG2 cells. This study clearly outlines the structural features of purified polysaccharides from P. portentosus under specific processing conditions, establishing a foundation for further investigation into the structure-activity relationship of these bolete polysaccharides.

Anti-Inflammatory, Anti-Hyperglycemic, and Anti-Aging Activities of Aqueous and Methanolic Fractions Obtained from Cucurbita ficifolia Bouché Fruit Pulp and Peel Extracts

The Cucurbita genus comprises various species that are globally consumed and that are commonly used for their nutritional value but also for medicinal applications. Within the Cucurbita genus can be found Cucurbita ficifolia Bouché, a species that is understudied regarding its potential value for the food industry, as a functional food, and for the pharmaceutical industry, as a source of nutraceuticals. Therefore, in this study we investigated the phytochemical composition and bioactivities of aqueous (AF) and methanolic (MF) fractions of C. ficifolia pulp and peel hydroethanolic (HE) extracts. HPLC-DAD-MSn and HPAEC-PAD analyses of extracts' fractions revealed a low content of polyphenols and a significant content of sugars. Through in vitro inhibition assays of the enzymes alpha-amylase, acetylcholinesterase (AChE), and elastase, all fractions showed, respectively, antidiabetic, neuroprotective, and anti-aging activities. The safety profile and anti-tumoral activities were evaluated in various cell models (Caco-2, HaCaT, HepG2, and RAW 264.7), and results showed that the fractions obtained from pulp extract induce no/low cytotoxicity, while the methanolic fraction of peel induced cytotoxicity in all cell lines. At non-cytotoxic concentrations, aqueous and methanolic fractions of both extracts significantly inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, revealing anti-inflammatory activity. Flow cytometry analysis showed that both aqueous fractions increased basal levels of glutathione (GSH) in Caco-2 cells, while not inducing oxidative stress, revealing potential as antioxidant dietary agents. However, the MF of peel HE extract induced oxidative stress in Caco-2 cells, as it increased reactive oxygen species (ROS) and lipid peroxidation. AF fraction of peel extract induced cell cycle arrest in the G0/G1 phase, while the other fractions induced cell cycle arrest in the S phase. In conclusion, Cucurbita ficifolia fruit presents potential as a functional food but also as a potential source of nutraceuticals, and peel waste products can be valorized by pharmaceutical and cosmeceutical industries as sources of bioactive molecules.

Bioactivity and application potential of O/W emulsions derived from carboxylic acid-based NADES-extracted total saponins from Polygonatum cyrtonema Hua

This study focuses on evaluating new methods for the green extraction of saponin compounds from Polygonatum cyrtonema Hua (PCH). This study utilized a combination of carboxylic acid-based natural deep eutectic solvents (NADES) and various extraction techniques including conventional heat reflux-, ultrasound-, and microwave-assisted extraction. The primary objectives were to assess total saponin yield, antioxidant capacity, and enzyme inhibition efficiency. Additionally, the solvents and extracts were evaluated for their antibacterial activity. Oil-in-water (O/W) emulsions of NADES extracts were also characterized and analyzed for stability. Results indicated that three NADES systems were effective in extracting saponins, with choline chloride and lactic acid (ChCl-LA) system being the most efficient. The ChCl:LA extract exhibited antimicrobial and antioxidant activities superior to conventional organic solvent extracts. Additionally, it demonstrated maximum inhibitory activity (IC50 values: 0.98 ± 0.03 and 1.46 ± 0.07 mg/mL, respectively) against α-glucosidase and α-amylase. The NADES extract as an aqueous phase significantly improved the stationarity of the O/W emulsion. Collectively, the study highlights the antimicrobial and technological advantages of NADES as a potential solvent for extracting saponin compounds from PCH.

In Vitro Studies of Pumpkin (Cucurbita moschata var. Kashi Harit) Seed Protein Fraction(s) to Evaluate Anticancer and Antidiabetic Properties

Chronic diseases like cancer and diabetes are the major public health concerns of India and worldwide. Nowadays, plant-derived products are in great demand for the treatment of these diseases. Pumpkin seeds are traditionally implicated for their pharmacological properties, as exemplified by benign prostatic hyperplasia. Earlier, pumpkin seed proteins were extracted by the Osborne method, and their functional and nutritional qualities were evaluated. Here, the aim is to assess in vitro, the anticancer and antidiabetic properties of seed protein fractions. HepG2, MDA-MB-231, and MCF-7 cell lines were treated with water-soluble (WF) and alkali-soluble fractions (AF) to assess cytotoxicity, while pancreatic β-cells and insulin resistance (IR) - HepG2 cell lines were treated with WF to evaluate the antidiabetic potential. WF and AF showed cytotoxic effects towards HepG2 and MDA-MB-231 cell lines, suggesting apoptosis-mediated anticancerous activity. WF potentiates glucose-stimulated insulin secretion in pancreatic β-cells, in a dose-dependent manner. In IR-HepG2 cell line studies, control, metformin, and WF-treated groups showed uptake of glucose, when compared to the diabetic group, which is well-correlated with the upregulated expressions of GLUT2 and GLUT4 transporters in these groups. These results indicate that proteins from WF and AF may have anticancerous and antidiabetic properties and thus have the potential to utilize pumpkin proteins in the management of cancer and diabetes.

Biosorption of Remazol Brilliant Blue R textile dye using Clostridium beijerinckii by biorefinery approach

The current study proposes RBBR biosorption by Clostridium beijerinckii DSMZ 6422 biomass remaining after biobutanol production from pumpkin peel (PP) by a zero-waste approach. Efficient biobutanol production was achieved by investigating initial PP concentrations (5-20% without or with enzymatic hydrolysis) and fermentation time. According to this, the highest concentrations of biobutanol and total ABE were obtained as 4.87 g/L and 8.13 g/L in the presence of 10% PP without enzymatic hydrolysis at 96 h. Furthermore, based on the zero-waste approach, C. beijerinckii DSMZ 6422 biomass obtained after biofuel production was used as a biosorbent for the removal of RBBR dye. Response surface methodology (RSM), commonly utilized for the experimental design, was used to specify the optimized biosorption conditions of RBBR, including initial dye concentration (50-200 mg/L), initial pH (2-6), biosorbent concentration (1-3 g/L), and contact time (0-240 min). The highest biosorption under optimized conditions with RSM was 98% in the presence of 194.36 mg/L RBBR and 2.65 g/L biosorbent at pH 2 and 15 min. This is the first report in the literature about the biosorption of RBBR dye by anaerobic C. beijerinckii biomass after the biobutanol production process. This study also shows the efficient usage of agricultural and microbial wastes in different areas based on zero-waste applications.

Progress of plant-derived non-starch polysaccharides and their challenges and applications in future foods

The development of future food is devoted not only to obtaining a sustainable food supply but also to providing high-quality foods for humans. Plant-derived non-starch polysaccharides (PNPs) are widely available, biocompatible, and nontoxic and have been largely applied to the food industry owing to their mechanical properties and biological activities. PNPs are considered excellent biomaterials and food ingredients contributing to future food development. However, a comprehensive review of the potential applications of PNPs in future food has not been reported. This review summarized the physicochemical and biological activities of PNPs and then discussed the structure-activity relationships of PNPs. Latest studies of PNPs on future foods including cell-cultured meat, food for special medical purposes (FSMPs), and three-dimensional-printed foods were reviewed. The challenges and prospects of PNPs applied to future food were critically proposed. PNPs with strong thermal stability are considered good thickeners, emulsifiers, and gelatinizers that greatly improve the processing adaptability of foods. The mechanical properties of PNPs and decellularized plant-based PNPs make them desirable scaffolds for cultured meat manufacturing. In addition, the biological activities of PNPs exhibit multiple health-promoting effects; therefore, PNPs can act as food ingredients producing FSMP to promote human health. Three-dimensional printing technology enhances food structures and biological activities of functional foods, which is in favor of expanding the application scopes of PNPs in future food. PNPs are promising in future food manufacturing, and more efforts need to be made to realize their commercial applications.

Arctium Lappa L

Arctium lappa L. is widely consumed for its various biological effects, and polysaccharides are its main functional components. The present study aimed to evaluate the immunoregulatory effects of the main polysaccharides from burdock (ALP-1) and reveal the underlying mechanisms. ALP-1 consisted of fructose and glucose (14.57:1) and had a molecular weight of 2757 Da, with typical characteristics of (1 → 2)-linked linear fructans. Oral intake of ALP-1 significantly increased the number of colonic goblet cells, serum immunoglobulin A and immunoglobulin G levels, and fecal secretory immunoglobulin A content as well as up-regulated antioxidant enzymes and increased short chain fatty acid production. In addition, ALP-1 administration regulated pro/anti-inflammatory cytokines (i.e., interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon-γ, and IL-10), intestinal microbiota structure, and the spatial information on key metabolites. Some gut-microbiota-mediated metabolic processes were also significantly altered. These results indicated that ALP-1 could exert beneficial effects on immune responses and intestinal health in healthy mice.

Preparation of a Novel Oat β-Glucan-Chromium(III) Complex and Its Hypoglycemic Effect and Mechanism

This study synthesized a novel oat β-glucan (OBG)-Cr(III) complex (OBG-Cr(III)) and explored its structure, inhibitory effects on α-amylase and α-glucosidase, and hypoglycemic activities and mechanism in vitro using an insulin-resistant HepG2 (IR-HepG2) cell model. The Cr(III) content in the complex was found to be 10.87%. The molecular weight of OBG-Cr(III) was determined to be 7.736 × 104 Da with chromium ions binding to the hydroxyl groups of OBG. This binding resulted in the increased asymmetry and altered spatial conformation of the complex along with significant changes in morphology and crystallinity. Our findings demonstrated that OBG-Cr(III) exhibited inhibitory effects on α-amylase and α-glucosidase. Furthermore, OBG-Cr(III) enhanced the insulin sensitivity of IR-HepG2 cells, promoting glucose uptake and metabolism more efficiently than OBG alone. The underlying mechanism of its hypoglycemic effect involved the modulation of the c-Cbl/PI3K/AKT/GLUT4 signaling pathway, as revealed by Western blot analysis. This research not only broadened the applications of OBG but also positioned OBG-Cr(III) as a promising Cr(III) supplement with enhanced hypoglycemic benefits.

Understanding Cr(III) Action on Mitochondrial ATP Synthase and AMPK Efficacy: Insights from Previous Studies-a Review

Chromium supplementation has been notably recognized for its potential health benefits, especially in enhancing insulin sensitivity and managing glucose metabolism. However, recent studies have begun to shed light on additional mechanisms of action for chromium, expanding our understanding beyond its classical effects on the insulin-signaling pathway. The beta subunit of mitochondrial ATP synthase is considered a novel site for Cr(III) action, influencing physiological effects apart from insulin signaling. The physiological effects of chromium supplementation have been extensively studied, particularly in its role in anti-oxidative efficacy and glucose metabolism. However, recent advancements have prompted a re-evaluation of chromium's mechanisms of action beyond the insulin signaling pathway. The discovery of the beta subunit of mitochondrial ATP synthase as a potential target for chromium action is discussed, emphasizing its crucial role in cellular energy production and metabolic regulation. A meticulous analysis of relevant studies that were earlier carried out could shed light on the relationship between chromium supplementation and mitochondrial ATP synthase. This review categorizes studies based on their primary investigations, encompassing areas such as muscle protein synthesis, glucose and lipid metabolism, and antioxidant properties. Findings from these studies are scrutinized to distinguish patterns aligning with the new hypothesis. Central to this exploration is the presentation of studies highlighting the physiological effects of chromium that extend beyond the insulin signaling pathway. Evaluating the various independent mechanisms of action that chromium impacts cellular energy metabolism and overall metabolic balance has become more important. In conclusion, this review is a paradigm shift in understanding chromium supplementation, paving the way for future investigations that leverage the intricate interplay between chromium and mitochondrial ATP synthase.

Isolation, characterization, trypsin inhibition, liver protective and antioxidant activities of arabinoxylan from Massa Medicata Fermentata and its processed products

Massa Medicata Fermentata (MMF) is a traditional Chinese medicine widely used in feed additives and human medicine. In this study, two neutral polysaccharides (SMMFP-1 and CMMFP-1) were isolated from two forms of MMF (sheng and chao MMF), and their structural characteristics and bioactivities were studied. The results showed that CMMFP-1 had higher average Mw compared with that of SMMFP-1. SMMFP-1 had a lower proportion of Ara, Xyl, GalA, and GlcA, but higher levels of Fuc, Gal, Man, and GulA. Compared with CMMFP-1, SMMFP-1 had a triple helix structure. SMMFP-1 had a layered structure, whereas CMMFP-1 had a curly layered structure. More glycosidic linkage types were found in SMMFP-1 than in CMMFP-1, and SMMFP-1 had a greater number of side chains. More importantly, SMMFP-1 showed better trypsin inhibition activity in vitro, liver-protective activity in vivo, and stronger antioxidant activity in vivo than CMMFP-1. Thus, arabinoxylans may be one of the active substances for different efficacies between MMF and its processed product. The results of this study facilitate the exploration of the correlation between the structural characteristics and biological functionalities of MMF arabinoxylans. Moreover, a theoretical basis is established for further study of the unique properties of arabinoxylans and their applications.

Research Advances of Modification and Nutraceutical Properties of Polysaccharide

As a group of important biopolymers, polysaccharides exist widely in living organisms and play many known and unknown biological roles in life activities via different pathways [...].

Preparation and Characterization of Ginger Peel Polysaccharide-Zn (II) Complexes and Evaluation of Anti-Inflammatory Activity

The present study aimed to explore the improvement of the bioactivity of ginger peel polysaccharides (GPs) by the modification of zinc after structural characterization. The obtained GP-Zn (II) complexes consisted dominantly of glucose and galactose in a mass proportion of 95.10:2.10, with a molecular weight of 4.90 × 10⁵ Da and a Zn content of 21.17 mg/g. The chelation of GPs and Zn (II) was mainly involved in the O-H of hydroxyl groups, and this interaction reduced the crystallinity and decreased the asymmetry of GPs, with a slight effect on the thermal stability. The administration of GPs and their Zn (II) complexes effectively alleviated CuSO₄-induced inflammatory response in zebrafish (Tg: zlyz-EGFP) via down-regulating the mRNA expression levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-12 and TNF-α) and upregulating the expression of anti-inflammatory cytokine (IL-10). Furthermore, the modification of Zn (II) enhanced the inflammation-inhibiting effect of polysaccharides. Therefore, GP-Zn (II) complexes could be applied as a candidate anti-inflammatory agent for the treatment of chronic inflammation-related diseases.