The Therapeutic Effect Of Licorice Flavonoids And Licochalcone A On Ulcerative Colitis And Its Molecular Mechanism

Licorice (Radix Glycyrrhizae), is traditionally used to treat various diseases including inflammation and gastric ulcers. Licorice is rich in flavonoid compounds, which possess anti-inflammatory activities. In this study, we investigated the protective effects of licorice flavonoids (LFs) on UC in mouse models and inti-tumor effect on the AOM/DSS induced colitis-associated colorectal cancer.Acute UC was induced by intra-rectal acetic acid (4% v/v) administration after pretreatment with LFs (100,200 and 400 mg/kg, p.o.),0.9% saline (20 ml/kg, p.o.), or SASP (600 mg/kg, p.o.) for 10 days. Our results showed that pre-treatment with LFs significantly reduced the colon wet weight/length ratio, percentage of affected area, macroscopic and histological damage scores, and colonic myeloperoxidase (MPO) activity as compared to the UC control group in a dose-dependent manner. LFs also significantly inhibited the NO while increased of both GSH and SOD. Moreover, LFs downregulated nuclear transcription factor kappa B (NF-κB) pathway and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Furthermore, LFs also showed obvious antiulcer effect on the DSS-induced UC model and anti-tumor effect on the AOM/DSS induced colitis-associated colorectal cancer.Quantitative analysis of chemical components of LFs was also conducted by FIPLC. Licochalcone A (Lico A) is a characteristic chalcone present in LFs. It has been proven to have the ability of anti-inflammatory, antioxidant, anti-parasitic and anti-cancer. We suggested Lico A might be the main anti-colitis component in LFs extracted in our study. At last, we investigated the effect of Lico A on dextran sulphate sodium-induced ulcerative colitis (UC) in a mouse model.Our data demonstrated that treatment with Lico A is effective for the prevention of DSS-induced UC mice and its effect may at least in part be due to its inhibition of NF-KB-regulated pro-inflammatory signaling and activation of Nrf2-regulated cytoprotective protein expression.Therefore, LFs and Lico A might be new and attractive chemoprevention agents for UC.