Search

Background: Oxidation has been reported as the one of the deterioration reactions of proteins in aquatic products. Searching for new bioactive substances from marine algae has been one of the main areas in food science and additives., Results: In this study, a novel protein from the red alga Porphyra haitanensis was determined after ammonium sulfate precipitation and gel filtration chromatography. It closely corresponded to the antioxidant activity and was identified as an uncharacterized protein with a molecular mass of 43 kDa, designated Ph43. Bioinformatic analysis revealed that Ph43 is a novel protein of non-phycobiliprotein family with putative chordin domains and rich in α-helical conformation. Recombinant protein (rPh43) was expressed in Escherichia coli as a Hig-tagged protein using a pET-22b vector system and purified by affinity high-performance liquid chromatography. Spectroscopy analysis revealed that there were no structural differences between rPh43 and natural recovered Ph43. Moreover, rPh43 showed equal/higher antioxidant activity compared with Ph43. rPh43 has the potential for application as a natural antioxidant for food stabilization., Conclusion: Our results identified a novel antioxidant protein with molecular mass of 43 kDa derived from Porphyra haitanensis that belongs to the non-phycobiliprotein family. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Degradation of sulphated polysaccharides from Grateloupia livida (GLP) was studied using H 2 O 2 -Vc combined with microwave treatment. Optimal conditions were determined after the Box-Behnken response surface analysis. The best degradation conditions were as follows: microwave power 250 W, microwave temperature 54 °C, the concentration of H 2 O 2 3 mM, degradation time 33 min. Under these conditions, the DPPH scavenging activity of the degraded GLP (DGLP) was 71.39 ± 0.17% at a concentration of 6.0 mg/mL. The degradation method is fast and effective, which is beneficial to improve the antioxidant activity of polysaccharides. Two sulphated polysaccharide constituents (DGLP-1 and DGLP-2) were isolated from DGLP and characterized, and their antioxidant activities were determined. The two polysaccharides had high sulphate content (sulphate content: 25.18-25.26%), contained galactose as the major monosaccharide, and had molecular weights of 158.49 ± 0.43 and 18.06 ± 0.92 kDa, respectively. Antioxidant assays suggested that DGLP-1 and especially DGLP-2 possessed good antioxidant properties., Competing Interests: Declaration of competing interest We declare that we have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The purpose of this study was to evaluate the antioxidant nature of tea polyphenol on S180 cells induced liver cancer in mice. In the present study, hepatocellular carcinoma was induced by tumor transplantation of liver in situ. The antitumor activity of tea polyphenol has been determined in vivo in hepatocellular carcinoma mice after treatment of drug (50, 100, 150 mg/kg body weight) by gavage for 20 days. Results showed that a significant increase in serum aspartate transaminase (AST), alkaline phosphatase (ALP), alanine aminotransfere (ALT), malondialdehyde (MDA) level, decrease in serum white blood cells (WBC), serum total protein (TP), albumin (ALB), A/G, tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ), liver reduced glutathione (GSH) levels were observed. In addition, the levels of enzymic and non-enzymic antioxidants were decreased when subjected to S180 cells induction. These altered enzyme levels were ameliorated significantly by administration of tea polyphenol at the concentration of 50, 100, 150 mg/kg body weight in drug-treated animals. These results indicate that the protective effect of tea polyphenol was associated with inhibition of MDA induced by S180 cells and to maintain the antioxidant enzyme levels.

The purpose of this study was to evaluate the antioxidant nature of tea polyphenol on S180 cells induced liver cancer in mice. In the present study, hepatocellular carcinoma was induced by tumor transplantation of liver in situ. The antitumor activity of tea polyphenol has been determined in vivo in hepatocellular carcinoma mice after treatment of drug (50, 100, 150 mg/kg body weight) by gavage for 20 days. Results showed that a significant increase in serum aspartate transaminase (AST), alkaline phosphatase (ALP), alanine aminotransfere (ALT), malondialdehyde (MDA) level, decrease in serum white blood cells (WBC), serum total protein (TP), albumin (ALB), A/G, tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ), liver reduced glutathione (GSH) levels were observed. In addition, the levels of enzymic and non-enzymic antioxidants were decreased when subjected to S180 cells induction. These altered enzyme levels were ameliorated significantly by administration of tea polyphenol at the concentration of 50, 100, 150 mg/kg body weight in drug-treated animals. These results indicate that the protective effect of tea polyphenol was associated with inhibition of MDA induced by S180 cells and to maintain the antioxidant enzyme levels. [ABSTRACT FROM AUTHOR]

In this study, two degraded polysaccharides were obtained by H 2 O 2 -Vc-ultrasonic and H 2 O 2 -Fe2+-ultrasonic treatment from Codium cylindricum. The basic structure of polysaccharides was characterized and the relationship between structure and antioxidant activity was studied. FTIR spectrum indicated that the degraded polysaccharides had similar functional groups (O H, C H, C O group) with ordinary polysaccharides. LC-MS analysis showed that the degraded polysaccharides were composed of the same monosaccharide units (mannose, galactose, arabinose, glucose, ribose) with Codium cylindricum polysaccharides, but the molar ratio was different. Meanwhile, the molecular weight and morphological feature of polysaccharides had been changed after degradation. Additionally, the antioxidant activity assay revealed that two degraded polysaccharides with lower molecular weight possessed better antioxidant property than ordinary polysaccharides. These results suggested that the basic structure of polysaccharides had not been damaged by two degradation methods, while the antioxidant activity was significantly enhanced. [ABSTRACT FROM AUTHOR]