Elaboration of Cationic Soluble Soybean Polysaccharides-Epigallocatechin Gallate Nanoparticles with Sustained Antioxidant and Antimicrobial Activities.

Epigallocatechin gallate (EGCG) is easily oxidized by environmental stress elements, including light, heat, and oxygen; thus, its biological activities can be reduced or even lost when exposed to a natural environment. Here, soluble soybean polysaccharide (SSPS) was successfully etherized by 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC), positively charged to extract cationic SSPS (CSSPS). Nanoparticles based on CSSPS can improve the encapsulation efficiency (EE) and sustained bioactivity of EGCG. The EE of EGCG by CSSPS was improved significantly as compared with that of SSPS due to the electrostatic interactions. Furthermore, the protective and sustained-release effects of CSSPS on EGCG in the EGCG-CSSPS nanoparticles (EGCG-CSSPS-NPs) markedly improved the sustained antioxidant and antimicrobial activities of EGCG, which was confirmed by the results of a salmon-preservation experiment. In addition, cytotoxicity tests showed that EGCG-CSSPS-NPs could effectively inhibit the proliferation of tumor cells but had no obvious toxicity to normal cells.

Protective mechanisms of three antioxidants against T-2 toxin-induced muscle protein deterioration in shrimp.

BACKGROUND: Quercetin (Q), tea polyphenols (TP), and rutin (R) are widely used plant-derived active ingredients. They possess antioxidant, anti-inflammatory, and anti-tumor properties, and can reduce the muscle damage caused by mycotoxins. However, few studies have examined the protective mechanisms of quercetin, tea polyphenols, and rutin on muscle quality. To elucidate their protective mechanisms, shrimp were exposed to both T-2 toxin and these three antioxidants for 20 days in a dose-escalating trial. The changes in the protein composition of shrimp muscle were measured. The target proteins associated with T-2 and antioxidants were screened and identified by non-labeled quantitative proteomics. RESULTS: The T-2 toxin induced abnormal expression of 21 target proteins, leading to the deterioration of muscle proteins in shrimp. The three antioxidants ameliorated the T-2 toxin-induced damage to muscle proteins by increasing the sarcoplasmic and myofibrillar protein content and decreasing the alkali-soluble protein content. Quercetin had the strongest protective effect. The protective processes of these antioxidants involved the upregulation of target proteins involved in carbohydrate metabolism (enolase, malate dehydrogenase), protein translation (elongation factor 1-alpha and eukaryotic translation initiation factor 2 subunit alpha), and cytoskeleton component (actin 2, fast-type skeletal muscle actin 1). Quercetin regulated the largest number of target proteins, making it the best protective agent against T-2 toxin. CONCLUSION: The T-2 toxin (4.80-24.30 mg/kg feed) induced changes in target proteins and muscle composition of shrimp, leading to a deterioration in muscle proteins. Quercetin (2.00-32.00 g/kg feed) had significant protective effects against this deterioration in muscle protein in shrimp. © 2022 Society of Chemical Industry.

Effect of T-2 toxin-injected shrimp muscle extracts on mouse macrophage cells (RAW264.7).

Following intramuscular injections of 0.1 mL, 3 mg kg-1 BW-1(1/10 LD50) T-2 toxin (T-2), the tissue concentration of T-2 in shrimp was quantitatively detected using LC-MS/MS. The biological half-time (t1/2) of T-2 in blood was 40.47 ± 0.24 min. The highest number of intramuscular T-2 shrimp could tolerate when given at blood t1/2 intervals was 4. The shrimps which were injected 5 T-2 died. The T-2 toxin highest accumulation was 0.471 ± 0.012 ng g-1 BW-1. The effect of toxic shrimp muscle subjected to different processing conditions (high pressure, trifluoroacetic acid, acid and alkali digestions, artificial digestive juice [to simulate exposure to gastric and intestinal juices]) on mouse macrophage cells (RAW267.4) were evaluated by the MTT assay. The inhibition ratio of 2% muscle extract on RAW267.4 was 85.70 ± 2.63%. The immunocytotoxicity of muscle extracts to RAW264.7 was highest in muscle extracts subjected to physical and chemical digestion (high pressure > NaOH > trifluoroacetic acid > 0.02 M HCl > 0.2 M HCl > controls), and also artificial digestion (artificial intestinal juice > artificial gastric juice > N type intestinal juice > N type gastric liquid > controls). Results showed that high-pressure and artificial intestinal juice were most effective in the release of modified T-2 to free T-2 thus enhancing toxicity. These results can be interpreted as measurement of T-2 in food being of little value because of enhanced toxicity of T-2-contaminated food as they pass through the gastrointestinal tract.