Antioxidant Activity of Gracilaria lemaneiformis Polysaccharide Degradation Based on Nrf-2/Keap-1 Signaling Pathway in HepG2 Cells with Oxidative Stress Induced by H2O2

Abstract

The objective of this research was to investigate the antioxidant activity of Gracilaria lemaneiformis polysaccharide degradation and its underlying mechanism involved in the Nrf-2/Keap-1 signaling pathway in HepG2 cells with oxidative stress induced by H2O2. The result of the scavenging ability of free radicals showed that GLP-HV (polysaccharide degraded by H2O2–vitamin C (Vc)) performed a better scavenging ability than GLP (G. lemaneiformis polysaccharide). Moreover, the scavenging ability of polysaccharide to these free radicals from strong to weak was as follows: superoxide radical, ferric ion, ABTS+, and DPPH radical, and their IC50 values were 3.56 ± 0.0028, 4.97 ± 0.18, 9.62 ± 0.35, and 23.85 ± 1.78 mg/mL, respectively. Furthermore, GLP-HV obviously relieved oxidative stress in HepG2 cells, which strengthened the activity of T-AOC, CAT, GSH-PX, and SOD, and diminished the intensity of MDA, intracellular ROS, and calcium ion based on the Nrf-2/Keap-1 signaling pathway. The PCR result revealed that polysaccharide upregulated the expression of the genes Nrf-2, HO-1, NQO-1, and ZO-1 and downregulated Keap-1. The correlation between chemical properties and antioxidant mechanism of GLP-HV was evaluated via a heat map. The results illustrated that reducing sugar and active groups presented a positive correlation, and molecular weight and viscosity exhibited a negative relation with antioxidant activity.

Effects of Polysaccharides-Rich Extract from <i>Gracilaria lemaneiformis</i> on Growth Performance, Antioxidant Capacity, Immune Function, and Meat Quality in Broiler Chickens

“…MDA levels indicate the degree of organic lipid peroxidation and are associated with cell damage ( Cheng et al, 2019 ). GLPs increase the activity of total antioxidant capacity, GSH-Px, CAT, and SOD, and decrease the concentrations of MDA and intracellular ROS in HepG2 cells ( Long et al, 2022 ). Wen et al (2017) report that GLPs enhance the activity of SOD, GSH-Px, and CAT and reduce MDA levels in the serum and liver of mice, exhibiting excellent antioxidant activity.…”

Mitigation of Paeoniae Radix Alba extracts on H2O2-induced oxidative damage in HepG2 cells and hyperglycemia in zebrafish, and identification of phytochemical constituents

“…where The HepG2 cells were cultured in DMEM medium containing 10% fetal bovine serum (FBS), 100 units/ml penicillin and 100 µg/ml streptomycin. To determine the toxicity of PRA extracts and H 2 O 2 , the viability of HepG2 cells was measured by CCK-8 assay (16). Briefly, the HepG2 cells (8.0 × 10 3 cells/well) were incubated in 96-well plates at 37 • C for 24 h in an MCO-18AC incubator (Panasonic, Japan) containing 5% CO 2 , followed by the addition of PRA extracts (25, 50, 100, 200, 400, and 800 µg/ml) for 24 h cultivation or H 2 O 2 (400, 500, 600, and 700 µM) for 6 h cultivation.…”

“…H 2 O 2 , as a considerably active oxygen molecule with relatively stable properties, is one of the main factors causing excessive oxidative stress, which is widely used to establish cell oxidative damage model (16,22). In this research, 400 ∼ 700 µM of H 2 O 2 were used to induce HepG2 cells for 6 h to establish the oxidative stress model.…”

Stabilization of High Internal Phase Oil-in-Water Emulsions Using “Whole” Gracilaria lemaneiformis Slurry

“…Seaweeds, also known as macroalgae, are a diverse group of marine plants that can be taxonomically classified into three main groups, namely, green, brown, and red [ 12 , 13 ]. These seaweeds are renowned for their substantial polysaccharide content, accompanied by minor proportions of proteins, lipids, and phenolic compounds, which contribute to their potential health benefits and diverse applications in the food industry [ 14 ].…”

“…Current research focuses on the extraction, structural characterization, and biological activity evaluation of active polysaccharides from GL. These polysaccharides exhibit antioxidant [ 13 ], anti-aging [ 15 ], and anti-tumor properties [ 16 ], as well as anti-allergic activity [ 17 ], and have shown promise in colitis treatment [ 18 ], gut microbiota balance [ 19 , 20 ], and blood glucose-lipid regulation [ 21 , 22 ]. However, a significant amount of residue is generated after extraction, necessitating further processing.…”