Longjing green tea (Camellia sinensis) extract dose-dependently influences intestinal barrier and liver inflammation in autoimmune hepatitis

Autoimmune hepatitis (AIH) refers to a liver disease in which the immune system abnormally attacks the cells. This study aimed to investigate effects of Longjing extract (LE) rich in polyphenols on intestinal flora of AIH. The S100-triggered AIH mice were intragastrically administrated with low, medium, or high doses of LE, and liver inflammation and pathology, intestinal physical and chemical barrier and flora composition were assessed in the respective group. This study indicated that low and medium doses of LE ameliorated the microflora disorder, intestinal barrier defect, and liver inflammation in AIH mice, whereas high doses exacerbated them. Furthermore, lipopolysaccharide/ toll-like receptor 4 involved in the regulation by LE. The dose-depended disparate effects of LE suggested that drinking tea in moderation are conducive to mitigating autoimmune liver injury, whereas the recommended supplement of polyphenols should be investigated in depth.