In vitro and in vivo antioxidant activity of eucalyptus leaf polyphenols extract and its effect on chicken meat quality and cecum microbiota.

While eucalyptus leaf polyphenols extract (EPE) has been evaluated for its various bioactivities, few studies thus far have focused on its systemic antioxidant activity or its effects in chickens in relation to meat quality or the intestinal microbiome. Therefore, the goal of this study was to investigate the antioxidant activity of EPE in vitro and in vivo, and to evaluate its effect on chicken meat quality and cecum microbiota. In this study, EPE scavenged DPPH free radical, ABTS free radical, and superoxide radical, and showed strong reducing power in chemical-based assay. EPE protected RAW264.7 cells from H2O2-induced oxidative damage by improving total superoxide dismutase (T-SOD) activity, catalase (CAT) activity and glutathione (GSH) content, decreasing malondialdehyde (MDA) content. Additionally, EPE dietary supplementation was found to increase chicken meat antioxidant levels and quality. Furthermore, chickens fed a diet supplemented with EPE had differentially changed cecal microbial compositions when compared to controls. EPE supplementation notably improved the α-diversity of the cecum. The Firmicutes/Bacteroidetes ratio and the relative abundance of Verrucomicrobia at the phylum level were clearly enhanced in the cecum with EPE supplementation (p < 0.05), with the relative abundance of Subdivision 5 genera incertae sedis and Aminivibrio enriched at genus level (p < 0.05). Therefore, these findings indicate that EPE is a good source of natural antioxidants and could be used as antioxidant supplements in animal feed and other foods, contributing to gut health improvement.

Anti-fat effect and mechanism of polysaccharide-enriched extract from Cyclocarya paliurus (Batal.) Iljinskaja in Caenorhabditis elegans.

Obesity is a global epidemic. Recent studies have shown that Cyclocarya paliurus (C. paliurus) leaves have the potential to alleviate fat deposits. However, the fat-reducing mechanism of it remains unclear. Using Caenorhabditis elegans (C. elegans) as a model, we found that C. paliurus polysaccharide (CPP) significantly decreased fat storage in both normal and high-fat worms without affecting the movement. Moreover, the size and number of lipid droplets were reduced in CPP-treated ZXW618 worms. In energy metabolism, CPP decreased Escherichia coli (E. coli) OP50 growth and pharyngeal pumping and increased the expression of vit-2. In lipid metabolism, CPP down-regulated the expression of the sbp-1 and nhr-49 genes by modulating mdt-15 to prevent the expression of the Δ9-desaturase genes (fat-5, fat-6 and fat-7). Meanwhile, the expression of the acs-2 genes, the downstream of nhr-49, was suppressed by CPP. These findings provided insights into the CPP-induced anti-fat mechanisms, which contributed to the application of CPP in anti-obesity drugs.