Preparation and characterization of garlic polysaccharide-Zn (II) complexes and their bioactivities as a zinc supplement in Zn-deficient mice

Research progress of edible mushroom polysaccharide-metal trace element complexes

Metal trace elements are crucial for human health, and the complexes of edible mushroom polysaccharides with metal trace elements are currently a research hotspot in the field of food science. This article reviews the preparation methods, structural characterization, and physiological activities of edible mushroom polysaccharide-metal trace element complexes, including iron, selenium, and zinc. Research has shown that iron complexes obtained through Co-thermal synthesis of the FeCl3 method exhibit excellent antioxidant and anti-anemia functions; selenium complexes prepared via selenium-enriched cultivation significantly enhance immunological and anti-cancer properties; zinc complexes improve lipid-lowering, liver protection, and antioxidant capabilities. However, there is an imbalance in research among different metal elements, particularly with a high density of studies on selenium complexes. These studies provide a foundation for the future development of edible mushroom polysaccharide-metal trace element complexes.

A glucose-rich heteropolysaccharide from Marsdenia tenacissima (Roxb.) Wight et Arn. and its zinc-modified complex enhance immunoregulation by regulating TLR4-Myd88-NF-κB pathway

A previously unreported immunological polysaccharide (MTP70-1) was obtained from Marsdenia tenacissima (Roxb.) Wight et Arn. MTP70-1 (2738 Da) is a heteropolysaccharide that mainly consists of (1 → 5)-linked-L-Araf, t-D-Glcp, (1 → 3,5)-linked-L-Araf, (1 → 4)-linked-D-Galp, (1 → 6)-linked-D-Glcp, and (1 → 3,6)-linked-D-Manp. In vitro cell assays revealed that MTP70-1 exhibits moderate immunomodulatory effects at the cellular level, and MTP70-1 was further modified with zinc to improve these effects. These modifications enhanced the immunomodulatory effects of MTP70-1, as phagocytosis was enhanced, the secretion of cytokines (TNF-α, IL-6, IL-1β, and IL-18) was increased, and the generation of chemokines (NO and ROS) in macrophages was enhanced. The intracellular mechanism by which MTP70-1 and MTP70-Zn activate macrophages was further revealed to be closely related to the TLR4-Myd88-NF-κB signaling pathway. In addition, a microscale thermophoresis binding (MST) assay confirmed that Zn modification can effectively enhance the binding affinity of MTP70-1 for TLR4. Ultimately, better immune-enhancing activity was attained with MTP70-Zn than MTP70-1. The immune-enhancing activity of MTP70-Zn was further demonstrated through zebrafish assays, which revealed that MTP70-Zn can effectively enhance the proliferation of macrophages and neutrophils.

Preparation, Structural Analysis, and Growth-Promoting Effects of Amomum longiligulare Polysaccharide 1-Mg (II) Complex

In this study, Amomum longiligulare polysaccharide 1 (ALP1) is used to chelate with magnesium (Mg) to synthesize the ALP1-Mg (II) complex (ALP1-Mg). Based on Box-Behnken response surface design, the optimum technological conditions are 22 mg mL-1 trisodium citrate, 2.10 mol L-1 MgCl2, reaction at 70 °C for 2.9 h, resulting in a maximum Mg content of 2.13%. Next, the physicochemical properties and structural characteristics of ALP1 and ALP1-Mg are characterized, and the results show that the morphology, conformation, crystallinity, and thermal stability of ALP1-Mg are changed. In addition, dietary supplementation of 500 mg kg-1 ALP1-Mg significantly reduces the feed conversion ratio during the grower (15-35 d). Meanwhile, the villus height/crypt depth of the duodenum and ileum are significantly increased, and the relative abundance of Lactobacillus is significantly elevated. Taken together, the results suggest that ALP1-Mg is a potential growth-promoting feed additive.

Sustainable production of extracellular polymeric substances and iron or copper complex from glutinous rice processing wastewater

Essential trace minerals play vital roles in maintaining human and animal health. However, an overdose of the existing inorganic trace minerals is prone to induce detrimental effects that outweigh positive benefits. In this study, an extracellular polymeric substances (EPS)-producing bacterium, identified as Bacillus licheniformis CCTCC M2020298, was isolated from marine using glutinous rice processing wastewater as enrichment medium. The EPS yield of Bacillus licheniformis CCTCC M2020298 could reach 8.62 g/L by using glutinous rice-processing wastewater containing medium. Furthermore, the potential of the EPS as a carrier for synthesizing EPS-iron (Fe) and EPS-copper (Cu) complex was explored. The results showed that the optimum condition for the synthesis EPS-Fe were the reaction temperature 70°C, pH 8.5–9.0 and mass ratio of EPS to trisodium citrate 2:1. The iron content of EPS-Fe reached 77.4 mg/g. Under the same condition, the copper content of EPS-Cu reached 90.7 mg/g. The elemental composition, functional groups and valence state of the mineral elements of EPS-Fe and EPS-Cu were well characterized. The EPS-Fe and EPS-Cu exhibited antioxidant activity in scavenging ·OH, DPPH and ·O2− free radicals, thereby leading to reduced oxidative stress and apoptosis levels in human colonic epithelial cells in vitro. They also inhibited the proliferation of mouse hepatocellular carcinoma H22 and the growth of intestinal pathogens in vitro. This study provided an effective avenue for EPS production from glutinous rice processing wastewater and proved the potential of EPS-Fe and EPS-Cu complexes as a new-type comprehensive essential trace mineral supplement.

Physicochemical, Structural, and Functional Properties of Fructans from Single-Clove Garlic and Multiclove Garlic: A Comparison

This study aimed to compare the structural features and functional properties of polysaccharides from single-clove garlic (SGPs) and multiclove garlic (MGPs) and to establish their structure-function relationships. Both SGPs and MGPs were identified as fructans consisting mainly of →1)-β-d-Fruf (2→ and →6)-β-d-Fruf (2→ residues but differed in average molecular weights (6.76 and 5.40 kDa, respectively). They shared similar thermodynamic properties, X-ray diffraction patterns, and high gastrointestinal digestive stability. These two purified fructans could dose-dependently scavenge free radicals, reduce oxidized metals, and effectively alleviate metronidazole-induced oxidative stress and CuSO4-induced inflammation in zebrafish via inhibiting the overexpression of inflammation-related proteins and cytokines. SGPs showed lower free radical scavenging activity in vitro than MGPs but higher antioxidant and anti-inflammatory activities in vivo. Taken together, the molecular weight was the main structural difference between the two garlic fructans of different varieties, which is a potential reason for their differences in biological activities.

Regulatory Effects Mediated by Enteromorpha prolifera Polysaccharide and Its Zn(II) Complex on Hypoglycemic Activity in High-Sugar High-Fat Diet-Fed Mice

In order to investigate and develop functional foods of marine origin with hypoglycemic activity, Enteromorpha prolifera polysaccharide-Zn(II) (EZ) complex was first prepared by marine resourced E. prolifera polysaccharide (EP) and ZnSO4 and their anti-diabetes activities against high-sugar and high-fat-induced diabetic mice were evaluated. The detailed structural characterization of EZ was elucidated by UV-Vis spectroscopy, infrared spectroscopy, and monosaccharide composition determination. The pharmacological research suggests that EZ has a potent hypoglycemic effect on high-sugar and high-fat-induced diabetic mice by inhibiting insulin resistance, improving dyslipidemia, decreasing inflammatory status, repairing pancreas damage, as well as activating the IRS/PI3K/AKT signaling pathway and regulating GLUT2 gene expression. At the same time, microbiota analysis indicates that a high dose of EZ could enhance the abundance of dominant species, such as Staphylococcaceae, Planococcaceae, Muribaculaceae, Aerococcaceae, and Lacrobacillaceae, in intestinal microbiota distribution. Thus, EZ could be considered as a potential candidate for developing an ingredient of functional foods for Zn(II) supplements with hypoglycemic activity.

Preparation of quinoa bran dietary fiber-based zinc complex and investigation of its antioxidant capacity in vitro

In order to improve the economic utilization of quinoa bran and develop a safe and highly available zinc ion biological supplement. In this study, a four-factor, three-level response surface optimization of quinoa bran soluble dietary fiber (SDF) complexation of zinc was studied. The effect used four factors on the chelation rate was investigated: (A) mass ratio of SDF to ZnSO₄.7H₂O, (B) chelation temperature, (C) chelation time, and (D) pH. Based on the results of the single-factor test, the four-factor three-level response surface method was used to optimize the reaction conditions. The optimal reaction conditions were observed as mentioned here: the mass ratio of quinoa bran SDF to ZnSO₄.7H₂O was 1, the reaction temperature was 65°C, the reaction time was 120 min, and the pH of the reaction system was 8.0. The average chelation rate was 25.18%, and zinc content is 465.2 μg/g under optimal conditions. The hydration method rendered a fluffy quinoa bran SDF structure. The intramolecular functional groups were less stable which made the formation of the lone pairs of electrons feasible to complex with the added divalent zinc ions to form a quinoa bran soluble dietary fiber-zinc complex [SDF-Zn(II)]. The SDF-Zn(II) chelate had higher 2,2-diphenylpicrylhydrazyl (DPPH), ABTS⁺, hydroxyl radical scavenging ability, and total antioxidant capacity. Therefore, metal ion chelation in dietary fiber is of biological importance.

Improving Dietary Zinc Bioavailability Using New Food Fortification Approaches: A Promising Tool to Boost Immunity in the Light of COVID-19

Zinc is a powerful immunomodulatory trace element, and its deficiency in the body is closely associated with changes in immune functions and viral infections, including SARS-CoV-2, the virus responsible for COVID-19. The creation of new forms of zinc delivery to target cells can make it possible to obtain smart chains of food ingredients. Recent evidence supports the idea that the optimal intake of zinc or bioactive compounds in appropriate supplements should be considered as part of a strategy to generate an immune response in the human body. Therefore, controlling the amount of this element in the diet is especially important for populations at risk of zinc deficiency, who are more susceptible to the severe progression of viral infection and disease, such as COVID-19. Convergent approaches such as micro- and nano-encapsulation develop new ways to treat zinc deficiency and make zinc more bioavailable.

Garlic polysaccharide-Cr (III) complexes with enhanced in vitro and in vivo hypoglycemic activities

This study aimed to prepare a complex of Cr (III) and garlic polysaccharides (GPs) and evaluate the in vitro and in vivo hypoglycemic activities of GPs and GP-Cr (III) complexes. The chelation of GPs with Cr (III) increased molecular weight, modified crystallinity, and altered morphological characteristics, through targeting the OH of hydroxyl groups and involving the C-O/O-C-O structure. The GP-Cr (III) complex had a higher thermal stability over 170-260 °C and higher stability throughout the gastrointestinal digestion. In vitro, the GP-Cr (III) complex exhibited a significantly stronger inhibitory effect against α-glucosidase compared with the GP. In vivo, the GP-Cr (III) complex at a high dose (4.0 mg Cr/kg body weight) generally had a higher hypoglycemic activity than the GP in (pre)-diabetic mice induced by a high-fat and high-fructose diet, based on indices like body weight, blood glucose levels, glucose tolerance, insulin resistance, insulin sensitivity, blood lipid levels, and hepatic morphology and function. Therefore, GP-Cr (III) complexes could be a potential Cr (III) supplement with an enhanced hypoglycemic activity.

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.