Synergistic effect of discrete ultrasonic and H2O2 on physicochemical properties of chitosan

Photodegradation of chitosan decorated by titanium dioxide: The potential to serve as a responded microcapsule shell

In order to develop the UV responded material, chitosan (CS) was decorated by TiO2, and the mechanism of UV-mediated photodegradation of CS-TiO2 was analyzed. In this study, the changes in color, microstructure, degradation rate, thermal stability, and structure under different treatments were explored. The results showed that CS could be degraded by UV light. With the increase of irradiation time, the degradation rate of CS significantly raised, and was up to 18.41 %. L⁎ value markedly decreased, a⁎ value and b⁎ value significantly increased. The photodegradation process fitted with first-order kinetics. The degradation was improved when reducing scale of TiO2 from 10 nm to 102 nm, increasing TiO2 addition, and increasing UV light power. UV irradiation would promote the breakage of β-1,4 glycosidic bonds and deacetylation of CS. After UV irradiation, the crystalline structure of CS was destroyed and thermal stability was reduced. Tea tree essential oil microcapsules were constructed by using CS-TiO2 as a UV-light-sensitive shell material and could achieve a rapid UV-light-triggered release process, with a significant increase in volatile substances after UV irradiation. Thus, CS decorated by TiO2 could function as a controlled-release shell for microcapsules, while UV light could act as a switch to modulate the release process.

Ultrasound-assisted H2O2 degradation enhances the bioactivity of Schizophyllan for wound healing and tissue regeneration

Background

Schizophyllan (SPG), a bioactive polysaccharide from Schizophyllum commune, possesses significant anti-inflammatory, antioxidant, and immunomodulatory properties. The molecular weight of polysaccharides significantly impacts their structural properties and biological functions. However, the functional characteristics of low molecular weight polysaccharides derived from Schizophyllum commune remain inadequately explored.

Methods

This study developed an ultrasound-assisted hydrogen peroxide (H2O2) degradation method to produce low-molecular-weight SPG with enhanced bioactivity. The process was optimized using response surface methodology, focusing on ultrasound duration, ultrasonic power, and H2O2 concentration. This approach effectively reduced the molecular weight of SPG from 4,409,608 Da to 257,500 Da, yielding three distinct variants: SPG-a (257,500 Da), SPG-b (429,300 Da), and SPG-c (364,800 Da). The bioactivity of these variants was assessed through in vitro cell proliferation and migration assays using BJ and HaCaT cells, as well as an in vivo zebrafish larval caudal fin regeneration model.

Results

In vitro, SPG-b significantly promoted cell proliferation, increasing BJ and HaCaT cells growth by 53.69% and 14.59%, respectively, at a concentration of 300 μg/mL (p < 0.05), compared to undegraded SPG. Additionally, scratch assays revealed that SPG-a enhanced BJ cells migration by 24.13% (p < 0.05), while SPG-b exhibited most pronounced effect on HaCaT cells migration (17.12%, p < 0.05), compared to the undegraded SPG. In vivo, SPG-c (3.125 mg/mL) significantly improved fin regeneration rates by 6.97% (p < 0.05) in zebrafish larvae, compared to the undegraded SPG.

Conclusion

This study demonstrates that ultrasound-assisted H2O2 degradation effectively reduces SPG molecular weight while enhancing its functional properties. These findings provide a foundation for the further development of SPG in pharmaceutical and cosmetic applications, highlighting its potential for broader utilization.

Acute Phytotoxicity and Antifungal Effect of Nanochitosan Particles on Colletotrichum fructicola with Low Susceptibility to Chitosan

Colletotrichum fungus complex affects several crops and tropical products, which suffer significant losses due to anthracnose. The use of chitosan nanoparticles (CNPs), alone or in combination with bioactive compounds, has been recommend for agronomic applications. However, there is very little information on their phytotoxicity, and there is no information about the effect on microorganisms with low susceptibility to chitosan. This work aims to compare their antifungal effect against isolates of C. fructicola with low susceptibility to chitosan and to study the toxicological effects of CNPs on the germination of lettuce (Lactuca sativa) and radish (Raphanus sativus) seeds. Levels of phytotoxicity of high-to-very high and moderate-to-very high were observed for lettuce and radish seeds, respectively, with greater detrimental effects on the radicle elongation after exposure to CNPs concentrations of 4-5 g L-1. For the three C. fructicola isolates, the CNPs did not inhibit the fungal growth; however, the cell viability decreased as the CNPs concentration increased, and a complete inhibition of the viability was found for H4-1 and 003 isolates at a CNPs concentration of 5 g L-1. Morphometric alterations characterized by a reduction in the average length of the terminal hyphae, distortion, and a higher number of branches in the hyphae, were observed. To our knowledge, this is the first report where the effect of nanochitosan particles in Colletotrichum fructicola, with experimentally proven low sensitivity to chitosan, was studied.

Potential skincare benefits and self-healing properties of Lignosus rhinocerotis polysaccharides as affected by ultrasound-assisted H2O2/Vc treatment

Natural polysaccharides have been recognized as major bioactive components in skincare and wound care products. In this study, the skincare benefits and self-healing properties of Lignosus rhinocerotis polysaccharides (LRP) and its degraded products (DLRP-1, DLRP-2 and DLRP-3) by ultrasound assisted H2O2/Vc treatment (U-H/V) at different ultrasonic intensity (28.14, 70.35, and 112.56 W/cm2) were investigated. U-H/V altered the internal crystalline structure and microstructure of LRP, and enhanced the thermal stability. Due to the breakage of molecular chains after U-H/V, the moisture absorption of LRP was enhanced but the moisturizing property showed a different degree of reduction. U-H/V significantly improved the antioxidant, anti-tyrosinase and anti-inflammatory activities of LRP. Furthermore, the results of enzyme kinetic studies showed a mixed competitive-noncompetitive inhibition of tyrosinase activity by DLRP-3 and the inhibition constant of DLRP-3 on tyrosinase was 2.97 mg/mL. The apparent viscosity of LRP dispersions showed a first increasing followed by decreasing trend as ultrasonic intensity rose. U-H/V enhanced the viscoelastic properties of LRP gels without destroying their self-healing properties. This findings reveal that U-H/V is beneficial for improving the skincare efficacy of LRP, providing a theoretical foundation for the applicability of LRP in wound dressings.

Effect of ultrasound assisted H2O2/Vc treatment on the hyperbranched Lignosus rhinocerotis polysaccharide: Structures, hydrophobic microdomains, and antitumor activity

The effect of ultrasonic intensity (28.14, 70.35, and 112.56 W/cm2) on Lignosus rhinocerotis polysaccharide (LRP) degraded by ultrasound assisted H2O2/Vc system (U-H/V) was investigated. U-H/V broke the molecular chain of LRP and improved the conformational flexibility, decreasing the molecular weight, intrinsic viscosity ([η]) and particle size. The functional groups and hyperbranched structure of LRP were almost stable after U-H/V treatment, however, the triple helix structure of LRP was partially disrupted. With increasing ultrasonic intensity, the critical aggregation concentration increased from 0.59 mg/mL to 1.57 mg/mL, and the hydrophobic microdomains reduced. Furthermore, the LRP treated with U-H/V significantly inhibited HepG2 cell proliferation by inducing apoptosis. The increase in antitumor activity of LRP was closely associated with the reduction of molecular weight, [η], particle size and hydrophobic microdomains. These results revealed that U-H/V treatment facilitates the degradation of LRP and provides a better insight into the structure-antitumor activity relationship of LRP.

Impact of Molecular Weight Variations in Dendrobium officinale Polysaccharides on Antioxidant Activity and Anti-Obesity in Caenorhabditis elegans

This research investigates the impact of Dendrobium officinale polysaccharides (DOP) with different molecular weights on antioxidant effects, lifespan enhancement, and obesity reduction, utilizing both in vitro analyses and the Caenorhabditis elegans (C. elegans) model. Through a series of experiments-ranging from the extraction and modification of polysaccharides, Gel Permeation Chromatography (GPC), and analysis of composition to the evaluation of antioxidant capabilities, this study thoroughly examines DOP and its derivatives (DOP5, DOP15, DOP25) produced via H2O2-Fe2+ degradation. The results reveal a direct relationship between the molecular weight of polysaccharides and their bioactivity. Notably, DOP5, with its intermediate molecular weight, demonstrated superior antioxidant properties, significantly extended the lifespan, and improved the health of C. elegans. Furthermore, DOP15 appeared to regulate lipid metabolism by affecting crucial lipid metabolism genes, including fat-4, fat-5, fat-6, sbp-1, and acs-2. These findings highlight the potential application of DOP derivatives as natural antioxidants and agents against obesity, contributing to the development of functional foods and dietary supplements.

Conventional extraction of fucoidan from Irish brown seaweed Fucus vesiculosus followed by ultrasound-assisted depolymerization

Fucoidan has attracted considerable attention from scientists and pharmaceutical companies due to its antioxidant, anticoagulant, anti-inflammatory, anti-tumor, and health-enhancing properties. However, the extraction of fucoidan from seaweeds often involves the use of harsh chemicals, which necessitates the search for alternative solvents. Additionally, the high viscosity and low cell permeability of high molecular weight (Mw) fucoidan can limit its effectiveness in drug action, while lower Mw fractions exhibit increased biological activity and are also utilized as dietary supplements. The study aimed to (1) extract fucoidan from the seaweed Fucus vesiculosus (FV) using an environmentally friendly solvent and compare it with the most commonly used extraction solvent, hydrochloric acid, and (2) assess the impact of ultrasound-assisted depolymerization on reducing the molecular weight of the fucoidan extracts and examine the cytotoxic effect of different molecular weight fractions. The findings indicated that the green depolymerization solvent, in conjunction with a brief ultrasound treatment, effectively reduced the molecular weight. Moreover, a significant decrease in cell viability was observed in selected samples, indicating potential anticancer properties. As a result, ultrasound was determined to be an effective method for depolymerizing crude fucoidan from Fucus Vesiculosus seaweed.

Effects of ultrasound-assisted H2O2 on the solubilization and antioxidant activity of yeast β-glucan

Yeast β-glucan (YG) possess an extensive range of biological activities, such as the inhibition of oxidation, but the poor water solubility of macromolecular YG limits its application. In this study, through the combined degradation of ultrasonic waves and H₂O₂, and the optimization of the main process parameters for solubilizing YG by response surface methodology (RSM), a new product of YG_UH was generated. The molecular weight, structural characteristics and degradation kinetics before and after solubilization were evaluated. The results showed that the optimal solubilization conditions were reaction time: 4 h, ultrasonic power: 3 W/mL, H₂O₂ concentration: 24 %. Under these conditions, ultrasound-assisted H₂O₂ increased the solubility (from 13.60 % to 70.00 %) and reduced molecular weight (from 6.73 × 10⁶ Da to 1.22 × 10⁶ Da). Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), Congo red (CR), scanning electron microscopy (SEM) revealed that ultrasound-assisted H₂O₂ increased the conformation's flexibility greatly, without changing the main structure of YG. More importantly, solubilization of YG improved free radical scavenging activity with YG_UH exhibiting the highest levels of DPPH and ABTS⁺ free radical scavenging activity. These results revealed that ultrasound-assisted H₂O₂ degradation could be a suitable way to increase the solubility of YG for producing value-added YG.