The in vitro antioxidant activity of water extract from Dictyophora indusiate was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonate) (ABTS) cation radical scavenging assays. Caenorhabditis elegans was used as a model organism to observe the effects of the extract at high (1.0 mg/mL), medium (0.5 mg/mL) and low (0.25 mg/mL) doses on oxidative and heat stress. In addition, the effects of the extract on fat deposition was analyzed by oil red O staining, and the level of triglyceride (TG) and the expression of fat metabolism-related genes in C. elegans were determined. The results showed that the extract enhanced antioxidant capacity in C. elegans. Its half maximal inhibitory concentrations on DPPH radical, hydroxyl radical and ABTS cation radical were 2.36, 1.44 and 0.86 mg/mL, respectively. The average life span of C. elegans under oxidative and heat stress was prolonged by 54.6% (P < 0.01) and 19.8% (P < 0.05) in the high-dose group, respectively. Compared with the control group, lipid deposition and TG level in the high-dose group decreased by 57.0% (P < 0.01) and 40.5% (P < 0.01), respectively. The mechanism may be that the water extract can down-regulate the regulation of mod-1, daf-1, fat-7, acs-2, daf-16 and mdt-15, up-regulate the expression levels of daf-2, sbp-1, nhr-49, fat-5 and fat-6, thereby improving lipid metabolism. These results show that the water extract of D. indusiate has antioxidant properties and can improve lipid metabolism.

This study aimed to explore the hepatoprotective effect of an enzymatic hydrolysate from oyster meat on chronic alcoholic liver injury in mice. After intervention with the hydrolysate, the serum levels of alaninetransaminase (ALT) activity, aspartate aminotransferase (AST) activity and total bile acid (TBA) concentration, liver index, and the contents of triglyceride (TG) and malondialdehyde (MDA) in the liver of mice with chronic alcoholic liver injury were measured, liver histomorphological changes were examined, and the mRNA transcription level of related genes in the liver and the changes of the gut microflora structure were analyzed. The results demonstrated that compared with the model group, the enzymatic hydrolysate at high and low doses significantly decreased the activity of serum ALT and AST and liver TG and MDA contents (P < 0.05, P < 0.01), but increased liver glutathione (GSH) content (P < 0.01). TBA content was significantly lower in the high-dose hydrolysate group (P < 0.05). The hydrolysate at high and low doses alleviated alcohol-induced liver damage in mice, and significantly down-regulated the mRNA transcription levels of the genes encoding toll-like recepror 4 (TLR4), tumor necrosis factor α (TNF-α), and nuclear factor-kappa B (NF-κB) (P < 0.05). The hydrolysate increased the abundance of Firmicutes as well as Lactobacillus and Alistipes, and reduced the abundance of Bacteroidetes in the gut of mice. In conclusion, the enzymatic hydrolysate can protect against chronic alcoholic liver injury in mice through reducing the activity of AST and ALT, and the contents of TG, MDA and TBA, increasing GSH content, down-regulating the mRNA transcription levels of TLR4, NF-κB and TNF-α, and changing the structure of the gut microflora.

Oyster enzymatic hydrolysate (OE) was fractionated by ultrafiltration into three fractions: OE-Ⅰ (< 5 kDa), OE-Ⅱ (5-10 kDa) and OE-Ⅲ (> 10 kDa). The in vitro antioxidant activities of the fractions were evaluated in terms of their 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion radical scavenging capacity and ferrous ion chelating capacity. Then, the effect of different doses of OE-Ⅰ on the lifespan, acute oxidative stress, thermal stress, antioxidant enzyme activities, reactive oxygen species (ROS) accumulation and cell apoptosis of Caenorhabditis elegans was investigated, and the expression levels of lifespan-related genes were measured to unravel the anti-aging mechanism of OE-Ⅰ. The results showed that OE-Ⅰ had the strongest antioxidant activity among the three fractions, and that high-dose of OE-Ⅰ significantly prolonged the lifespan of C. elegans (P < 0.01). The activities of superoxide dismutase (SOD) (P < 0.05), catalase (CAT) and glutathione peroxidase (GSH-Px) (P < 0.01) were significantly increased and the accumulation of ROS and cell apoptosis were decreased. In addition, the expression of the skn-1, daf-16, sod-3 and mtl-1 genes were up-regulated, while the expression of the daf-2 and age-1 genes were down-regulated, suggesting improved stress resistance of C. elegans. To sum up, OE-Ⅰ can be used as a functional food base material for anti-oxidation and anti-aging.