title: Indole compounds may be promising medicines for ulcerative colitis.
abstract: Indole compounds are extracted from indigo plants and have been used as blue or purple dyes for hundreds of years. In traditional Chinese medicine, herbal agents in combination with Qing-Dai (also known as indigo naturalis) have been used to treat patients with ulcerative colitis (UC) and to remedy inflammatory conditions. Recent studies have noted that indole compounds can be biosynthesized from tryptophan metabolites produced by various enzymes derived from intestinal microbiota. In addition to their action on indole compounds, the intestinal microbiota produce various tryptophan metabolites that mediate critical functions through distinct pathways and enzymes. Furthermore, some indole compounds, such as indigo and indirubin, act as ligands for the aryl hydrocarbon receptor. This signaling pathway stimulates mucosal type 3 innate lymphoid cells to produce interleukin-22, which induces antimicrobial peptide and tight junction molecule production, suggesting a role for indole compounds during the mucosal healing process. Thus, indole compounds may represent a novel treatment strategy for UC patients. In this review, we describe the origin and function of this indole compound-containing Chinese herb, as well as the drug development of indole compounds.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Sugimoto
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Naganuma
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. takagast@z2.keio.jp.
authors.forename: Takanori
authors.initials: T
authors.lastname: Kanai
mesh_terms: D003093:Colitis, Ulcerative / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D016896:Treatment Outcome
chemical_list: D004365:Drugs, Chinese Herbal; C530990:Qingdai compound
keywords: Aryl hydrocarbon receptor; Chinese herbal medicine; Indole; Inflammatory bowel diseases; Ulcerative colitis