Plant green pigment of chlorophyllin attenuates inflammatory bowel diseases by suppressing autophagy activation in mice

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are intestinal complications characterized by chronic inflammation, autophagy abnormality, and lysosomal stress, which are derived from genetic predisposition and environmental risk factors. It is generally precepted that dietary green vegetable is beneficial for physiological homeostasis. In this study, we found that dextran sulfate sodium (DSS)-induced colitis and altered intestinal epithelia in mice were attenuated by oral administration of chlorophyllin (CHL), a water-soluble derivate of chlorophyll. In DSS-treated mice, autophagy was persistently activated in intestinal tissues and associated with bowel disorders. Conversely, supplement of CHL in diet or gavage suppressed intestinal inflammation, downregulated autophagy flux in intestinal tissue, and relieved endoplasmic reticulum stress. In vitro studies show that CHL could activate Akt and mTOR pathways, leading to downregulation of autophagic and lysosomal flux. Thus, consumption of green vegetables and chlorophyllin may be beneficial for IBD recovery in part through alleviation of inflammation and autolysosomal flux. NEW & NOTEWORTHY Inflammatory bowel disease (IBD) is a chronic and recurrent gastrointestinal disease, while the etiology remains poorly understood. Dietary composition and lifestyle are crucial for pathogenesis and progression of IBD. In this study, we observed that autophagy in the intestinal tissue was persistently activated in IBD mice. Chlorophyllin (CHL), a water-soluble derivate of chlorophyll, can attenuate colitis by regulating autophagy and inflammation. Thus, consumption of green vegetables and chlorophyllin may be beneficial for IBD recovery.