A Critical Review of the Abilities, Determinants, and Possible Molecular Mechanisms of Seaweed Polysaccharides Antioxidants

Toward Enhanced Antioxidant and Protective Potential: Conjugation of Corn Cob Xylan with Gallic Acid as a Novel Approach

Maize ranks as the second most widely produced crop globally, yielding approximately 1.2 billion tons, with corn cob being its primary byproduct, constituting 18 kg per 100 kg of corn. Agricultural corn production generates bioactive polysaccharide-rich byproducts, including xylan (Xyl). In this study, we used the redox method to modify corn cob xylan with gallic acid, aiming to enhance its antioxidant and protective capacity against oxidative stress. The conjugation process resulted in a new molecule termed conjugated xylan-gallic acid (Xyl-GA), exhibiting notable improvements in various antioxidant parameters, including total antioxidant capacity (1.4-fold increase), reducing power (1.2-fold increase), hydroxyl radical scavenging (1.6-fold increase), and cupric chelation (27.5-fold increase) when compared with unmodified Xyl. At a concentration of 1 mg/mL, Xyl-GA demonstrated no cytotoxicity, significantly increased fibroblast cell viability (approximately 80%), and effectively mitigated intracellular ROS levels (reduced by 100%) following oxidative damage induced by H2O2. Furthermore, Xyl-GA exhibited non-toxicity toward zebrafish embryos, offered protection against H2O2-induced stress, and reduced the rate of cells undergoing apoptosis resulting from H2O2 exposure. In conclusion, our findings suggest that Xyl-GA possesses potential therapeutic value in addressing oxidative stress-related disturbances. Further investigations are warranted to elucidate the molecular structure of this novel compound and establish correlations with its pharmacological activities.

Optimization of Exopolysaccharide Produced by Lactobacillus plantarum R301 and Its Antioxidant and Anti-Inflammatory Activities

In this study, the yield of exopolysaccharide (EPS) from Lactobacillus plantarum R301 was optimized using a single-factor experiment and response surface methodology (RSM). After optimization, the EPS yield was increased with a fold-change of 0.85. The significant factors affecting EPS production, as determined through a Plackett-Burman design and Central Composite Design (CCD), were MgSO₄ concentration, initial pH, and inoculation size. The maximum yield was 97.85 mg/mL under the condition of 0.01% MgSO₄, an initial pH 7.4, and 6.4% of the inoculation size. In addition, the EPS exhibited strong antioxidant activity, as demonstrated by its ability to scavenge DPPH, ABTS, and hydroxyl radicals. The scavenging rate was up to 100% at concentrations of 4 mg/mL, 1 mg/mL, and 2 mg/mL, respectively. Moreover, the EPS also exhibited reducing power, which was about 30% that of ascorbic acid when both tended to be stable with the increased concentration. These results suggest that L. plantarum R301 EPS possesses different antioxidant mechanisms and warrants further investigation. In addition to its antioxidant activity, the EPS also demonstrated good anti-inflammatory activity by inhibiting the inflammation induced by lipopolysaccharide (LPS) in RAW 264.7 cells, which could decrease nitric oxide (NO) production and expression of the proinflammatory cytokine Il-6. These findings suggest that L. plantarum R301 EPS could be used as a potential multifunctional food additive in the food industry.

Comparison of the Effects of Enzymolysis Seaweed Powder and Saccharomyces boulardii on Intestinal Health and Microbiota Composition in Kittens

Kittens are prone to intestinal health problems as their intestines are not completely developed. Seaweed is rich in plant polysaccharides and bioactive substances that are highly beneficial to gut health. However, the effects of seaweed on cat gut health have not been assessed. This study compared the effects of dietary supplementation with enzymolysis seaweed powder and Saccharomyces boulardii on the intestinal health of kittens. In total, 30 Ragdoll kittens (age: 6 months; weight: 1.50 ± 0.29 kg) were assigned to three treatment groups for a 4-week feeding trial. The dietary treatment given was as follows: (1) basal diet (CON); (2) CON + enzymolysis seaweed powder (20 g/kg of feed) mixed evenly with the diet (SE); and (3) CON + Saccharomyces boulardii (2 × 10¹⁰ CFU/kg of feed) mixed evenly with the diet (SB). Compared with the CON and SB groups, dietary supplementation with the enzymolysis seaweed powder improved the immune and antioxidant capacity and also reduced the intestinal permeability and inflammation levels of kittens. The relative abundance of Bacteroidetes, Lachnospiraceae, Prevotellaceae, and Faecalibacterium in the SE group was higher than those in the CON and SB groups (p ≤ 0.05), while the relative abundance of Desulfobacterota, Sutterellaceae, and Erysipelatoclostridium in the SB group was lower than that in the SE group (p ≤ 0.05). Moreover, enzymolysis seaweed powder did not alter the level of intestinal SCFAs in kittens. Conclusively, supplementing kitten diet with enzymolysis seaweed powder can promote intestinal health by enhancing the gut barrier function and optimizing the microbiota composition. Our findings provide new perspectives on the application of enzymolysis seaweed powder.

Application of logistic regression, support vector machine and random forest on the effects of titanium dioxide nanoparticles using macroalgae in treatment of certain risk factors associated with kidney injuries

The use of titanium dioxide (TiO₂) nanoparticles in many biological and technical domains is on the rise. There hasn't been much research on the toxicity of titanium dioxide nanoparticles in biological systems, despite their ubiquitous usage. In the current investigation, samples were exposed to various dosages of TiO₂ nanoparticles for 4 days, 1 month, and 2 months following treatment. ICP-AES was used to dose TiO₂ into the tissues, and the results showed that the kidney had a significant TiO₂ buildup. On the other hand, apoptosis of renal tubular cells is one of the most frequent cellular processes contributing to kidney disease (KD). Nevertheless, the impact of macroalgal seaweed extract on KD remains undetermined. In this work, machine learning (ML) approaches have been applied to develop prediction algorithms for acute kidney injury (AKI) by use of titanium dioxide and macroalgae in hospitalized patients. Fifty patients with (AKI) and 50 patients (non-AKI group) have been admitted and considered. Regarding demographic data, and laboratory test data as input parameters, support vector machine (SVM), and random forest (RF) are utilized to build models of AKI prediction and compared to the predictive performance of logistic regression (LR). Due to its strong antioxidant and anti-inflammatory powers, the current research ruled out the potential of using G. oblongata red macro algae as a source for a variety of products for medicinal uses. Despite a high and fast processing of algorithms, logistic regression showed lower overfitting in comparison to SVM, and Random Forest. The dataset is subjected to algorithms, and the categorization of potential risk variables yields the best results. AKI samples showed significant organ defects than non-AKI ones. Multivariate LR indicated that lymphocyte, and myoglobin (MB) ≥ 1000 ng/ml were independent risk parameters for AKI samples. Also, GCS score (95% CI 1.4-8.3 P = 0.014) were the risk parameters for 60-day mortality in samples with AKI. Also, 90-day mortality in AKI patients was significantly high (P < 0.0001). In compared to the control group, there were no appreciable changes in the kidney/body weight ratio or body weight increases. Total thiol levels in kidney homogenate significantly decreased, and histopathological analysis confirmed these biochemical alterations. According to the results, oral TiO₂ NP treatment may cause kidney damage in experimental samples.

Seaweed for climate mitigation, wastewater treatment, bioenergy, bioplastic, biochar, food, pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

Comparison of in vitro and in vivo antioxidant activities of commercial fucoidans from Macrocystis pyrifera, Undaria pinnatifida, and Fucus vesiculosus

Antioxidants fucoidans from three seaweeds, Undaria pinnatifida (FUP), Macrocystis pyrifera (FMP) and Fucus vesiculosus (FFV) are sold commercially. However, it is unclear which fucoidan is the most potent antioxidant. Therefore, our objective was to compare the antioxidant activities of these fucoidans. For this purpose, six in vitro antioxidant tests were used, total antioxidant capacity, hydroxyl radical scavenging assay, ferrous and cupric chelating assay, reducing power and H2O2 scavenging assay. The data showed that the fucoidans had a low capacity to donate electrons, and a low capacity to chelate metals. The best activity obtained was in the scavenging of hydroxyl radical. When macrophages were exposed to H2O2 and fucoidans, MTT and live/dead assays showed that all fucoidans protected cells from oxidative damage. The survival rate of zebrafish embryos was significantly higher when exposed to H2O2 and fucoidans than H2O2 alone. In summary, the fucoidans evaluated were ranked according to their antioxidant activity as follows: FMP > FFV > FUP, and the results suggest that these fucoidans, mainly FMP, can be used in the formulation of medicines/foods.

Antioxidant Activity of Fucoidan Modified with Gallic Acid Using the Redox Method

Antioxidant compounds decrease the amount of intracellular reactive oxygen species (ROS) and, consequently, reduce the deleterious effects of ROS in osteoblasts. Here, we modified a 21 kDa fucoidan (FucA) with gallic acid (GA) using the redox method, to potentiate its antioxidant/protective capacity on pre-osteoblast-like cells (MC3T3) against oxidative stress. The 20 kDa FucA-GA contains 37 ± 3.0 mg GA per gram of FucA. FucA-GA was the most efficient antioxidant agent in terms of total antioxidant capacity (2.5 times), reducing power (five times), copper chelation (three times), and superoxide radical scavenging (2 times). Exposure of MC3T3 cells to H2O2 increased ROS levels and activated caspase-3 along with caspase-9. In addition, the cell viability decreased approximately 80%. FucA-GA also provided the most effective protection against oxidative damage caused by H2O2. Treatment with FucA-GA (1.0 mg/mL) increased cell viability (~80%) and decreased intracellular ROS (100%) and caspase activation (~80%). In addition, Fuc-GA (0.1 mg/mL) abolished H2O2-induced oxidative stress in zebra fish embryos. Overall, FucA-GA protected MC3T3 cells from oxidative stress and could represent a possible adjuvant for the treatment of bone fragility by counteracting oxidative phenomena.

A Fucan Sulfate with Pentasaccharide Repeating Units from the Sea Cucumber Holothuriafloridana and Its Anticoagulant Activity

A fucan sulfate (HfFS) was isolated from the sea cucumber Holothuriafloridana after proteolysis-alkaline treatment and purified with anion-exchange chromatography. The molecular weight (Mw) of HfFS was determined to be 443.4 kDa, and the sulfate content of HfFS was 30.4%. The structural analysis of the peroxidative depolymerized product (dHfFS-1) showed that the primary structure of HfFS was mainly composed of a distinct pentasaccharide repeating unit -[l-Fuc_2S4S-α(1,3)-l-Fuc-α(1,3)-Fuc-α(1,3)-l-Fuc_2S-α(1,3)-l-Fuc_2S-α(1,3)-]_n-. Then, the “bottom-up” strategy was employed to confirm the structure of HfFS, and a series of fucooligosaccharides (disaccharides, trisaccharides, and tetrasaccharides) were purified from the mild acid-hydrolyzed HfFS. The structures identified through 1D/2D NMR spectra showed that these fucooligosaccharides could be derivates from the pentasaccharide units, while the irregular sulfate substituent also exists in the units. Anticoagulant activity assays of native HfFS and its depolymerized products (dHf-1~dHf-6) in vitro suggested that HfFS exhibits potent APTT-prolonging activity and the potencies decreased with the reduction in molecular weights, and HfFS fragments (dHf-4~dHf-6) with Mw less than 11.5 kDa showed no significant anticoagulant effect. Overall, our study enriched the knowledge about the structural diversity of FSs in different sea cucumber species and their biological activities.

Protective action of polysaccharides from Laurencia papillose (Rhodophyta) against imidacloprid induced genotoxicity and oxidative stress in male albino rats

Imidacloprid (IMI), the main component of neonicotinoid insecticides, promotes oxidative stress and genotoxicity in mammals. The aim of this experiment is to assess oxidative stress in liver cells and genotoxicity of erythrocytes for rats exposed to sub-lethal doses of IMI and the protective effects for Rhodophyta as antioxidant material versus imidacloprid. A total of 30 adult male albino rats (average body weight, 190–200 g) were divided into six groups (n=5) as follows: group 1 served as the control, group 2 received 200 mg/kg red algae, group 3 received 45 mg/kg IMI (high-dose group), group 4 received 22.5 mg/kg IMI (low-dose group), group 5 received 200 mg/kg red algae +45 mg/kg IMI, and group 6 received 200 mg/kg red algae +22.5 mg/kg IMI. After 28 d of treatment, the antioxidant activity of the crude extract of red algae was assessed in terms of free radical scavenging activity and found to be higher in TCA (75.57%) followed by DPPH (50.08%) at concentration 100 μg extract and a significant increase in lipid peroxidation and reductions in glutathione were observed in liver cells were intoxicated with high and low doses of IMI. Moreover decreases in catalase and glutathione peroxidase parameters in same previous groups which indicated oxidative stress. In addition significant increases in micronucleus frequency (MN) in the bone marrow of the rats as a genotoxicity marker which indicated DNA damage in erythrocytes cells with alterations in the histopathology of liver cells were also noted such as necrosis, inflammatory cells, infiltration, and necrobiotic changes. Whereas Rhodophyta succeeded in alleviation the oxidative damage and genotoxicity induced by the insecticide. In conclusion, IMI demonstrates hazardous effects, such as alterations in antioxidant status and mutagenicity of erythrocytes and polysaccharides from Rhodophyta has good antioxidant activity in vivo model systems against imidacloprid.

Structure Elucidation of Fucan Sulfate from Sea Cucumber Holothuria fuscopunctata through a Bottom-Up Strategy and the Antioxidant Activity Analysis

Fucan sulfate I (FSI) from the sea cucumber Holothuria fuscopunctata was purified and its structure was clarified based on a bottom-up strategy. The unambiguous structures of a series of oligosaccharides including disaccharides, trisaccharides, and tetrasaccharides, which were released from mild acid hydrolysis of FSI, were identified by one-dimensional (1D)/two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. All the glycosidic bonds in these oligosaccharides were presented as α1,3 linkages confirmed by correlated signals from their ¹H-¹H ROESY and ¹H-¹³C HMBC spectra. The structural sequence of these oligosaccharides formed by Fuc_2S4S, Fuc_2S, and non-sulfated ones (Fuc_0S), along with the general structural information of FSI, indicated that the structure of FSI could be elucidated as: [-L-Fuc_2S4S-α1,3-L-Fuc_(2S)-α1,3-L-Fuc_2S-α1,3-L-Fuc_0S-α1,3-1-]_n. Moreover, the L-Fuc_0S-α1,3-L-Fuc_2S4S linkage in FSI was susceptible to be cleaved by mild acid hydrolysis. The antioxidant activity assays in vitro showed that FSI and the depolymerized product (dFSI') had potent activities for superoxide radical scavenging activity with IC₅₀ of 65.71 and 83.72 μg/mL, respectively, while there was no scavenging effect on DPPH, hydroxyl and ABTS radicals.

Antioxidant effects of seaweeds and their active compounds on animal health and production - A Review

Natural antioxidants applied as feed additives can improve not only animals’ health and overall performance but also increase their resistance to environmental stress such as heat stress, bad housing conditions, diseases, etc. Marine organisms, for example seaweeds – red, brown, and green macroalgae contain a plethora of biologically active substances, including phenolic compounds, polysaccharides, pigments, vitamins, micro- and macroelements, and proteins known for their antioxidant activity, which can help in the maintenance of appropriate redox status in animals and show pleiotropic effects for enhancing good health, and productivity. The dysregulated production of free radicals is a marked characteristic of several clinical conditions, and antioxidant machinery plays a pivotal role in scavenging the excessive free radicals, thereby preventing and treating infections in animals. Supplementation of seaweeds to animal diet can boost antioxidant activity, immunity, and the gut environment. Dietary supplementation of seaweeds can also enhance meat quality due to the deposition of marine-derived antioxidant components in muscles. The use of natural antioxidants in the meat industry is a practical approach to minimize or prevent lipid oxidation. However, overconsumption of seaweeds, especially brown macroalgae, should be avoided because of their high iodine content. An important point to consider when including seaweeds in animal feed is their variable composition which depends on the species, habitat, location, harvest time, growing conditions such as nutrient concentration in water, light intensity, temperature, etc. This review highlights the beneficial applications of seaweeds and their extracted compounds, which have antioxidant properties as feed additives and impact animal health and production.

Effects of multi-frequency ultrasonic on the physicochemical properties and bioactivities of polysaccharides from different parts of ginseng

The effect of multi-frequency ultrasonic extraction (MUE) on the yields, physicochemical properties, antioxidant and α-glucosidase inhibitory activities of polysaccharides (GPs) from different parts of ginseng were compared. Results demonstrated that yields of polysaccharides from different parts were found to vary significantly differences, in the order of roots (M-GRPs) > flowers (M-GFPs) > leaves (M-GLPs). Compared with heat reflux extraction, MUE not only increased the yield of GPs by up to 9.14%-210.87%, with higher uronic acid content (UAC: increased by 4.99%-53.48%), total phenolics content (TPC: increased by 7.60% to 42.61%), total flavonoids content (TFC: increased by 2.52%-5.45%), and lower molecular weight (Mw: reduced by 6.51%- 33.08%) and protein content (PC: reduced by 5.15%-8.95%), but also improved their functional properties and bioactivities. All six purified polysaccharides extracted by MUE were acidic pyran polysaccharide with different monosaccharide composition, possessed remarkable antioxidant and α-glucosidase inhibitory activities. Especially, M-GFP-1 exhibited the highest bioactivities, illustrated that the activities were highly correlated with UAC and TPC, Mw, and triple helical structure. These results indicate that MUE was an efficient technique for improving yields, physicochemical and functional properties and enhancing biological activities of polysaccharide.

Polysaccharide-Based Nanocomposites for Food Packaging Applications

The article presents a review of the literature on the use of polysaccharide bionanocomposites in the context of their potential use as food packaging materials. Composites of this type consist of at least two phases, of which the outer phase is a polysaccharide, and the inner phase (dispersed phase) is an enhancing agent with a particle size of 1-100 nm in at least one dimension. The literature review was carried out using data from the Web of Science database using VosViewer, free software for scientometric analysis. Source analysis concluded that polysaccharides such as chitosan, cellulose, and starch are widely used in food packaging applications, as are reinforcing agents such as silver nanoparticles and cellulose nanostructures (e.g., cellulose nanocrystals and nanocellulose). The addition of reinforcing agents improves the thermal and mechanical stability of the polysaccharide films and nanocomposites. Here we highlighted the nanocomposites containing silver nanoparticles, which exhibited antimicrobial properties. Finally, it can be concluded that polysaccharide-based nanocomposites have sufficient properties to be tested as food packaging materials in a wide spectrum of applications.