Characterization and bioactivity of phlorotannin loaded protein-polysaccharide nanocomplexes

Optimized microwave-assisted extraction and characterization of spray dried Luffa aegyptiaca nanomucilage: Physicochemical properties, biological activities, and anticancer efficacy against MCF-7 human breast cancer cells

Microwave-assisted extraction conditions were optimized using response surface methodology to evaluate the effects of extraction parameters on the yield and carbohydrate content of Luffa aegyptiaca mucilage. The optimal extraction parameters were determined at 540 W for 2 min with a 1:20 (g/mL) ratio, yielding a maximum of 5.90 % (w/w) and comprising 63 % carbohydrate content, which includes glucose, galactose, maltose, mannose, and galacturonic acid, characterized by β (1 → 4) and β (1 → 6) glycosidic bonds. The nanomucilage exhibited a monomodal particle size distribution of 145.3 ± 4.60 nm, high thermal stability (-1363.08 J/g), oil and water retention capacity, emulsifying ability (93.06 ± 0.48 %), emulsifying stability (75.02 ± 0.96 %), solubility (95.36 ± 0.89 %), and foaming ability (93.06 ± 0.48 %). Mucilage demonstrated potential in vitro anti-oxidant activity (2.05 ± 0.10 %) against Caco-2 cells, anti-inflammatory activity during membrane stabilization (30.47 ± 0.42 % to 70.46 ± 0.31 %,) and protein denaturation (20.47 ± 0.42 % to 78.39 ± 0.40 %) assays and anticancer activity against human breast cancer cells (MCF-7), with growth inhibition of 100.5 ± 12.45 %. Hence, this evaluation of Luffa aegyptiaca nanomucilage highlights its potential as a multifunctional biomaterial with significant applications in the healthcare industry.

Genipin crosslinked sodium caseinate-chitosan oligosaccharide nanoparticles for optimizing β-carotene stability and bioavailability

In this study, genipin served as crosslinker to combine sodium caseinate (SC) and chitosan oligosaccharide (COS), aiming to improve the physicochemical properties and encapsulation efficiency of SC in delivering hydrophobic nutritional factors. The genipin crosslinked complex of SC and COS (GSCC) was characterized by circular dichroism spectrum and infrared spectrum analyses. Nanoparticles produced from GSCC (GSCCNP) exhibited a superior hydrophilicity compared to those derived from SC (SCNP). GSCCNP significantly augmented the encapsulation efficacy and photostability of β-carotene. β-Carotene encapsulated within GSCCNP (βC-GSCCNP) exhibited remarkable in vitro sustained release characteristics and heightened bioavailability. In addition, βC-GSCCNP showed significant in vitro anti-inflammatory activity. These findings indicated that genipin crosslinking COS-modified SC could construct a nano-delivery system to enhance the stability and bioavailability of insoluble nutritional factors, thereby presenting promising applications for hydrophobic nutrients in the development of functional foods and beverages.

Preparation and characterization of bovine serum albumin/chitosan composite nanoparticles for delivery of Antarctic krill peptide

BACKGROUND

Antarctic krill peptide (AKP) has gained considerable interest because of its multiple biological functions. However, its application may be limited by its poor stability and susceptibility to degradation. Encapsulation of AKP using a nanoparticle delivery system is an effective way to overcome these problems. In the present study, bovine serum albumin (BSA) and chitosan (CS) were used as delivery vehicles to encapsulate AKP.

RESULTS

The results revealed that the particle size (83.3 ± 4.4-222.4 ± 32.7 nm) and zeta-potential (35.1 ± 0.7-45.0 ± 2.7 mV) of nanoparticles (NPs) increased with the increasing content of BSA, but the polydispersity index decreased (1.000 ± 0.002 to 0.306 ± 0.011). Hydrogen bonding, hydrophobic and electrostatic interactions were the main forces to form BSA/CS-AKP NPs. X-ray diffraction revealed that AKP was encapsulated by BSA/CS. Scanning electron microscopy images exhibited that the NPs were spherical in shape, uniform in size and tightly bound. BSA/CS-AKP NPs exhibited excellent stability in the pH range (2-5) and after 15 days of storage, and could hinder the release of AKP in simulated gastric environment and promote the release of AKP in simulated intestinal environment. After simulated digestion, the hypoglycemic activity of encapsulated AKP was better than that of unencapsulated AKP.

CONCLUSION

Our results revealed that the BSA/CS showed great potential for protecting and delivering AKP. © 2024 Society of Chemical Industry.

The influence of drying methods on extract content, tyrosinase activity inhibition, and mechanism in Ascophyllum nodosum: A combined microstructural and kinetic study

This study evaluates vacuum drying (VD), microwave drying (MD), hot air drying (HAD), and freeze drying (FD), on the color and microstructure changes of Ascophyllum nodosum (A. nodosum), which affect the extraction of polyphenols and flavonoids. During drying, VD and FD show slight color change and looser structure, aiding in active compound preservation and extraction. Polyphenols extracted from A. nodosum (PEAn) using these methods show higher anti-tyrosinase activity, with VD treatment exhibiting the strongest inhibition. Kinetic studies demonstrate competitive inhibition between PEAn and tyrosinase. The binding constant (Ki) values indicate that PEAn treated with VD exhibits the most effective inhibition on tyrosinase, and the Zeta potential suggests the formation of the most stable complex. Circular dichroism (CD) spectroscopy shows significant enzyme rearrangement with VD-treated PEAn. Molecular docking confirms strong binding affinity. This study aims to enhance the utility of A. nodosum and develop novel uses for tyrosinase inhibitors in food.

Phycocyanin-phlorotannin complexes improve the structure and functional properties of yogurt

Adding natural bioactive ingredients to yogurt can improve the nutritional and physiological benefits. In this study, we used ultrasonic-assisted phlorotannin from Ascophyllum nodosum (A. nodosum) modified phycocyanin (PC) to form a complex (UPP) to produce a fortified fermented yogurt. The effects of PC and UPP on the structure, stability, and function of fermented yogurt within 7 days were assessed using physicochemical properties, texture analysis, rheological testing, 16S rDNA sequencing analysis, and lipidomics analysis. Molecular docking indicated that PC might bind to phlorotannin via ARG-77, ARG-84, LEU-120, ALA-81, CYS-82, and ASP-85 sites.When the mass ratio of the complex is 1:1, the ability of UPP1:1 to remove DPPH· scavenging ability in an acid environment increased by about 50 %. UPP1:1 with more acid stability changed the microstructure of the yogurt, enhanced the stability of the yogurt, improved the antioxidant properties, and inhibited the growth of harmful bacteria within 7 days. This work encouraged the extraction and use of phlorotannin from edible brown algae and offered a straightforward method for making yogurt supplemented with PC.

Formation and non-covalent interactions of binary and ternary complexes based on β-casein, Lentinus edodes mycelia polysaccharide, and taxifolin

Polyphenols, polysaccharides, and proteins are essential nutrients and functional substances present in food, and when present together these components often interact with each other to influence their structure and function. Proteins and polysaccharides are also excellent carrier materials for polyphenols. In this context, this study investigated the non-covalent interactions between taxifolin (TAX), Lentinus edodes mycelia polysaccharide (LMP), and β-casein (β-CN). β-CN and LMP spontaneously formed nanocomplexes by hydrogen bonds and van der Waals forces. The quenching constant and binding constant were (1.94 ± 0.02) × 1013 L mol-1 s-1 and (3.22 ± 0.17) × 105 L mol-1 at 298 K, respectively. The altered conformation of β-CN, resulting from the binding to LMP, affected the interaction with TAX. LMP significantly enhanced the binding affinity of TAX and β-CN, but did not change the static quenching binding mode. The binding constant for β-CN-TAX was (3.96 ± 0.09) × 1013 L mol-1, and that for the interaction between TAX and β-CN-LMP was (32.06 ± 0.05) × 1013 L mol-1. In summary, β-CN-LMP nanocomplexes have great potential as a nanocarrier for polyphenols, and this study provides a theoretical foundation for the rational design of non-covalent complexes involving LMP and β-CN, both in binary and ternary configurations.

Sodium-alginate-based indicator film containing a hydrophobic nanosilica layer for monitoring fish freshness

In this study, hydrophobic sodium alginate/anthocyanin/cellulose nanocrystal indicator films were fabricated by incorporating nanosilica (NS) as a waterproofing layer. The concentrations and formation methods (spraying (S), coating (C), and impregnation (I)) of the NS layer (denoted as NSS, NSC, NSI, respectively) were optimized. The results indicated that the optimum concentration of the NS layer was 5 % at a water contact angle (WCA) 110.5°. Further, Fourier transform infrared spectra showed the presence of SiOSi and SiCH3 groups in the NSS, NSC, and NSI films, and X-ray diffraction spectra indicated that original structures of these films were disordered. Moreover, the surface morphology, mechanical properties, and light transmission were affected by the NS layer, and the optimal layer was found to be NSI. After 10 days of storage at 100 % humidity, the NSI film exhibited low water vapor adsorption (37.22 g) and permeability (0.1484 g/m·s·Pa·10-11) and a high WCA (110.2°). In addition, the NSI film exhibited a visible color shift with an increasing pH of the buffer solution. A monitoring test of fish freshness showed that the NSI film displayed a distinctive color change corresponding to fish spoilage during 14 days of storage. This indicates that NSI has high potential in indicator film applications.

Improving potential strategies for biological activities of phlorotannins derived from seaweeds

Seaweeds have garnered considerable attention due to their capacity to serve as exceptional reservoirs of numerous bioactive metabolites possessing substantial chemical and biological significance. .Phlorotannins constitute a significant class of natural polyphenols originating from brown seaweeds, featuring a broad spectrum of bioactive attributes and demonstrating potential applicability across various sectors. The potential health advantages associated with phlorotannins, particularly concerning the prevention of conditions linked to oxidative stress, such as inflammation, diabetes, and allergies, have generated substantial interest within the food and pharmaceutical industries. Nevertheless, current research remains insufficient in providing a comprehensive understanding of their absorption, as comparisons drawn with their terrestrial counterparts remain speculative. It is commonly presumed that phenolic compounds, including phlorotannins, face challenges due to their limited solubility, instability, and extensive metabolism, all of which restrict their bioavailability. In order to circumvent these limitations and amplify their utility as components of medicinal formulations or healthcare products, researchers have explored various strategies, including the encapsulation or integration of phlorotannins into nano-/micro-particles or advanced drug delivery systems. This review offers a thorough exploration of the structural and biological attributes of phlorotannins and furnishes insights into potential strategies showing promise for their effective utilization in preclinical and clinical applications.

Fractionation of Arctic Brown Algae (Fucus vesiculosus) Biomass Using 1-Butyl-3-methylimidazolium-Based Ionic Liquids

Arctic brown algae are considered a promising industrial-scale source of bioactive sub-stances as polysaccharides, polyphenols, and low-molecular secondary metabolites. Conventional technologies for their processing are focused mainly on the isolation of polysaccharides and involve the use of hazardous solvents. In the present study a "green" approach to the fractionation of brown algae biomass based on the dissolution in ionic liquids (ILs) with 1-butil-3-methylimidazolium (bmim) cation with further sequential precipitation of polysaccharides and polyphenols with acetone and water, respectively, is proposed. The effects of IL cation nature, temperature, and treatment duration on the dissolution of bladderwrack (Fucus vesiculosus), yields of the fractions, and their chemical composition were studied involving FTIR and NMR spectroscopy, as well as size-exclusion chromatography and monosaccharide analysis. It was shown that the use of bmim acetate ensures almost complete dissolution of plant material after 24 h treatment at 150 °C and separate isolation of the polysaccharide mixture (alginates, cellulose, and fucoidan) and polyphenols (phlorotannins) with the yields of ~40 and ~10%, respectively. The near-quantitative extraction of polyphenolic fraction with the weight-average molecular mass of 10-20 kDa can be achieved even under mild conditions (80-100 °C). Efficient isolation of polysaccharides requires harsh conditions. Higher temperatures contribute to an increase in fucoidan content in the polysaccharide fraction.

Structural characterization and stability of glycated bovine serum albumin-kaempferol nanocomplexes

Kaempferol (Kae), a flavonoid is endowed with various functions. However, due to its poor water solubility and stability, its application in the food and pharmaceutical fields remains elusive. Emerging reports have emphasized the importance of bovine serum albumin (BSA), and glycosylated BSA (GBSA) prepared in the nature deep eutectic solvent system as drug delivery system carriers. In our study, ultraviolet and fluorescence spectra revealed the higher interactions of BSA and GBSA with Kae. Through analysis of Z-average diameter, zeta-potential, polydispersity index (PDI), encapsulation efficiency (EE), loading capacity (LC) of BSA-Kae nanocomplexes (NPs) and GBSA-Kae NPs, GBSA-Kae NPs showed a higher absolute value of zeta-potential and lower PDI, while its EE and LC were also higher. Structural characterization and stability analysis revealed that GBSA-Kae NPs had more stable properties. This study laid the theoretical foundation for improving the solubility and stability of Kae during its delivery and transport.

Nanoencapsulation Motivates the High Inhibitive Ability of Fucoxanthin on H2O2-Induced Human Hepatocyte Cell Line (L02) Apoptosis via Regulating Lipid Metabolism Homeostasis

This study reports an encapsulation system for fucoxanthin (FX) through simple affinity binding with gelatin (GE) and then coating with chitosan oligosaccharides (COS). The effects of FX before and after encapsulation on the human hepatocyte cell line (L02) were investigated. FX-GE and FX-GE-COS nanocomplexes exhibited a spherical shape with diameters of 209 ± 6 to 210 ± 8 nm. FX-GE-COS nanocomplexes were found to perform the best with the highest encapsulation efficiency (EE, 83.88 ± 4.39%), improved FX stability, and enhanced cellular uptake on the nanoscale. The cytotoxicity and cell mitochondrial damage of H₂O₂ exposure to L02 cells decreased with the increase of free-FX and FX-GE-COS nanocomplexes. FX-GE-COS nanocomplexes' intervention decreased the intracellular ROS and inhibited the apoptosis of L02 cells that was induced by H₂O₂ exposure in a concentration-dependent manner. Lipidomic analysis revealed that FX-GE-COS nanocomplexes could regulate the lipid metabolism disturbed by H₂O₂ and protected the mitochondrial function of L02 cells. These results suggested that nanoencapsulation enhanced the antioxidant activity of FX to L02 cells, and the constructed FX-GE-COS nanocomplexes have the potential to be an antioxidant nutritional dietary supplement.

Ultrasound treatment enhanced the functional properties of phycocyanin with phlorotannin from Ascophyllum nodosum

Introduction

Phycocyanin offers advantageous biological effects, including immune-regulatory, anticancer, antioxidant, and anti-inflammation capabilities. While PC, as a natural pigment molecule, is different from synthetic pigment, it can be easily degradable under high temperature and light conditions.

Methods

In this work, the impact of ultrasound treatment on the complex of PC and phlorotannin structural and functional characteristics was carefully investigated. The interaction between PC and phlorotannin after ultrasound treatment was studied by UV–Vis, fluorescence spectroscopy, circular dichroism (CD) spectroscopy, fourier transform infrared (FTIR) spectroscopy. Additionally, the antioxidant potential and in vitro digestibility of the complexes were assessed.

Results

The result was manifested as the UV–Vis spectrum reduction effect, fluorescence quenching effect and weak conformational change of the CD spectrum of PC. PC was identified as amorphous based on the X-ray diffraction (XRD) data and that phlorotannin was embedded into the PC matrix. The differential scanning calorimetry (DSC) results showed that ultrasound treatment and the addition of phlorotannin could improve the denaturation peak temperatures (Td) of PC to 78.7°C. In vitro digestion and free radical scavenging experiments showed that appropriate ultrasound treatment and the addition of phlorotannin were more resistant to simulated gastrointestinal conditions and could improve DPPH and ABTS+ free radical scavenging performance.

Discussion

Ultrasound treatment and the addition of phlorotannin changed the structural and functional properties of PC. These results demonstrated the feasibility of ultrasound-assisted phlorotannin from A. nodosum in improving the functional properties of PC and provided a possibility for the application of PC-polyphenol complexes as functional food ingredients or as bioactive materials.

Sargassum filipendula, a Source of Bioactive Compounds with Antioxidant and Matrix Metalloproteinases Inhibition Activities In Vitro with Potential Dermocosmetic Application

The antioxidant and the potential inhibitory capacity of matrix metalloproteinases of the phlorotannin-type polyphenolic and fucoidan-type polysaccharides extracts obtained from the macroalga S. filipendula were evaluated. Through chromatographic and spectroscopic techniques, the corresponding chemical structure of compounds present in the extracts was determined. Antioxidant capacity was evaluated using the methyl linoleate model for the inhibition of lipid peroxidation, and the free radical scavenging capacity was assessed using DPPH, ABTS, •OH, O2•− methods. The matrix metalloproteinase inhibition potential was measured by collagenase and elastase inhibition tests, using epigallocatechin gallate as a positive control. The extracts exhibited a high scavenging capacity of radical species evaluated and inhibition of diene conjugate formation and thiobarbituric acid reactive substances. The results showed that the crude extracts presented dose-dependent collagenase and elastase inhibition, with IC50 values between 0.04 and 1.61 mg/mL. The structure of the residues of the polysaccharide was identified mainly as (1→3)-sulfated (1→3) α-l-fucopyranose at carbon 4 and residues of β-d-glucopyranose, α-d-Mannopyranose, and β-d-Galactopyranose, while in the polyphenol extract the presence of phloroglucinol was identified and the presence of eckol, bifuhalol, and trifuhalol was suggested. Our results allow us to infer that S. filipendula is a potential source of bioactive ingredients with antioxidant and anti-aging activity.

Separation and Structural Characterization of a Novel Exopolysaccharide from Rhizopus nigricans

The present study aims to analyze the structural characterization and antioxidant activity of a novel exopolysaccharide from Rhizopus nigricans (EPS2-1). For this purpose, EPS2-1 was purified through DEAE-52, Sephadex G-100, and Sephadex G-75 chromatography. The structural characterization of EPS2-1 was analyzed using high-performance gel permeation chromatography (HPGPC), Fourier transform infrared spectroscopy (FT-IR), methylation analysis, nuclear magnetic resonance (NMR) spectra, transmission electron microscope (TEM), and atomic force microscope (AFM). The results revealed that EPS2-1 is composed of mannose (Man), galactose (Gal), glucose (Glc), arabinose (Ara), and Fucose (Fuc), and possesses a molecular weight of 32.803 kDa. The backbone of EPS2-1 comprised →2)-α-D-Manp-(1→ and →3)-β-D-Galp-(1→, linked with the O-6 position of (→2,6)-α-D-Manp-(1→) of the main chain is branch α-D-Manp-(1→6)-α-D-Manp-(1→, linked with the O-6 positions of (→3)-β-D-Galp-(1→) of the main chain are branches →4)-β-D-Glcp-(1→ and →3)-β-D-Galp-(1→, respectively. Finally, we demonstrated that EPS2-1 also shows free radical scavenging activity and iron ion reducing ability. At the same time, EPS2-1 could inhibit the proliferation of MFC cells and increase the cell viability of RAW264.7 cells. Our results suggested that EPS2-1 is a novel polysaccharide, and EPS2-1 has antioxidant activity. In addition, EPS2-1 may possess potential immunomodulatory and antitumor activities. This study promoted the application of EPS2-1 as the functional ingredients in the pharmaceutical and food industries.

Recent advances in biological properties of brown algae-derived compounds for nutraceutical applications

The increasing demand for nutraceuticals in the circular economy era has driven the research toward studying bioactive compounds from renewable underexploited resources. In this regard, the exploration of brown algae has shown significant growth and maintains a great promise for the future. One possible explanation could be that brown algae are rich sources of nutritional compounds (polyunsaturated fatty acids, fiber, proteins, minerals, and vitamins) and unique metabolic compounds (phlorotannins, fucoxanthin, fucoidan) with promising biological activities that make them good candidates for nutraceutical applications with increased value-added. In this review, a deep description of bioactive compounds from brown algae is presented. In addition, recent advances in biological activities ascribed to these compounds through in vitro and in vivo assays are pointed out. Delivery strategies to overcome some drawbacks related to the direct application of algae-derived compounds (low solubility, thermal instability, bioavailability, unpleasant organoleptic properties) are also reviewed. Finally, current commercial and legal statuses of ingredients from brown algae are presented, considering future therapeutical and market perspectives as nutraceuticals.

Advanced Coatings with Antioxidant and Antibacterial Activity for Kumquat Preservation

An active coating is one of the best ways to maintain the good quality and sensory properties of fruits. A new active coating was prepared by incorporating curcumin and phloretin into the konjac glucomannan matrix (KGM-Cur-Phl). The fourier infrared spectroscopy, rheology and differential scanning calorimetry confirmed the successful fabrication of this coating. This coating showed excellent antioxidant activity revealed by the 95.03% of ABTS radicals scavenging ratio and 99.67% of DPPH radicals scavenging ratio. The result of bacteria growth curves showed that it could effectively inhibit the growth of Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Salmonella typhimurium. The results of firmness, titratable acid and pH showed that it effectively prolonged the shelf life of kumquat. A novel konjac glucomannan-based active coating was provided.

Phloroglucinol and Its Derivatives: Antimicrobial Properties toward Microbial Pathogens

Phloroglucinol (PG) is a natural product isolated from plants, algae, and microorganisms. Aside from that, the number of PG derivatives has expanded due to the discovery of their potential biological roles. Aside from its diverse biological activities, PG and its derivatives have been widely utilized to treat microbial infections caused by bacteria, fungus, and viruses. The rapid emergence of antimicrobial-resistant microbial infections necessitates the chemical synthesis of numerous PG derivatives in order to meet the growing demand for drugs. This review focuses on the use of PG and its derivatives to control microbial infection and the underlying mechanism of action. Furthermore, as future perspectives, some of the various alternative strategies, such as the use of PG and its derivatives in conjugation, nanoformulation, antibiotic combination, and encapsulation, have been thoroughly discussed. This review will enable the researcher to investigate the possible antibacterial properties of PG and its derivatives, either free or in the form of various formulations.

Phlorotannins-bioactivity and extraction perspectives

Phlorotannins, a seaweed based class of polyphenolic compounds, have proven to possess potential bioactivities such as antioxidant, antimicrobial, anti-allergic, anti-diabetic, anti-inflammatory, anti-cancerous, neuroprotection etc. These bioactivities have further increased demand globally and sustainable techniques such as supercritical fluid extraction, microwave assisted extraction, enzyme assisted extraction, extraction using deep eutectic solvents etc. are being explored currently for production of phlorotannin-rich extracts. In spite of such well documented bioactivities, very few phlorotannin-based nutraceuticals are available commercially which highlights the significance of generating consumer awareness about their physiological benefits. However, for industry level commercialization accurate quantification of phlorotannins with respect to the different classes is vital requiring sophisticated analytical techniques such as mass spectrometry, ¹H-NMR spectroscopy etc. owing to the wide structural diversity. This review summarizes the extraction and bioactivities of phlorotannins based on the findings of in vivo and in vitro studies.