Comprehensive Assessment of the Safety of Eucommia ulmoides Leaf Extract for Consumption as a Traditional Chinese Health Food

To ensure the export quality of Eucommia ulmoides leaf extract(ELE)and facilitate E.ulmoides leaf inclusion in the directory of traditional Chinese health foods,an overall safety assessment of ELE was performed,including genotoxicity and long-term toxicity,according to the national food safety standards of China.No variations in the reverse mutation number of the nominal bacterial strains were observed under ELE treatment in comparison with the solvent control.Additionally,the micronucleus rates of in vivo mammalian erythrocytes and in vitro mammalian cells under ELE treatment were equivalent to or significantly lower than those of the solvent control.The fold change in the trifluorothymidine resistance mutation frequency of the thymidine kinase gene under ELE treatment was less than three times in comparison with the solvent control,suggesting that ELE did not cause genotoxicity.Moreover,animal experiments showed that the growth performance of rats under ELE treatment was enhanced because the body weights of rats increased.No oxidative injury or inflammatory responses were induced and no histopathological lesions of tissues were detected under ELE treatment.In addition,plasma triglycerides and low-density lipoprotein cholesterol levels significantly decreased,and plasma high-density lipoprotein cholesterol levels significantly increased with ELE treatment,suggesting that ELE was health-promoting.Furthermore,moderate to excellent antimicrobial activities,a favorable anticancer capacity,and superior antioxidant abilities of ELE were found,implying ELE possesses good bioactivities.Therefore,we affirmed ELE is safe to consume as a traditional Chinese health food.

Dietary Eucommia ulmoides leaf extract improves laying performance by altering serum metabolic profiles and gut bacteria in aged laying hens

The leaves of Eucommia ulmoides are rich in bioactive constituents that have potential gastrointestinal benefits for animals.In aged laying hens,intestinal health issues contribute to a significant decline in egg-laying capacity during intermediate and later stages.It remains unclear whether E.ulmoides leaf extract(ELE)can improve intestinal health and enhance egg production in elderly laying hens,and the underlying mechanisms are yet to be elucidated.Therefore,we conducted a study with 480 laying hens(65 weeks old)randomly allocated into four groups:a control group fed with the basal diet,and three treatment groups supplemented with 500,1,000,and 2,000 mg/kg of ELE,respectively.The primary active constituents of ELE include flavonoids,polysaccharides,terpenoids,and phenolic acids.Dietary supplementation with ELE at 1,000 mg/kg(ELE1000)significantly improved laying performance and egg quality compared to the other groups.ELE1000 stimulated the maturation of intestinal epithelial cells,increased villus height,and reduced crypt depth.It also influenced the levels of proteins associated with tight junctions(claudin-1 and claudin-2)and intestinal inflammatory factors(IL-6,IL-1β,and IL-2)in different intestinal sections.Integrative analysis of serum metabolomics and gut microbiota revealed that ELE1000 improved nutrient metabolism by modulating amino acid and ubiquinone biosynthesis and influenced the abundance of intestinal microbiota by enriching pivotal genera such as Bacteroides and Rikenellaceae_RC9_gut_group.We identified 15 metabolites significantly correlated with both gut microbiota and laying performance,e.g.,DL-methionine sulfoxide,THJ2201 N-valerate metabolite,tetracarbonic acid,etc.In conclusion,ELE1000 improved laying performance in elderly laying hens by affecting intestinal morphology,barrier function,microbiota,and serum metabolite profiles.These findings suggest that ELE can be a beneficial feed additive for extending the peak producing period in aged laying hens.