XANTHINE OXIDASE INHIBITOR

PURPOSE:A xanthine oxidase inhibitor, containing a partially novel indole derivative as a main constituent, and useful as a preventing and treating agent for gout, calculus in the urinary organ systems and tissue degeneration in the circulatory systems, etc. CONSTITUTION:A xanthine oxidase inhibitor containing an indole derivative expressed by formula I (R and R are H, OH, acyloxy or tosyloxy; R is hydroxymethyl, carboalkoxyl or formyl) as a main constituent. The above-mentioned compound is a substance extracted and isolated from commercially available picrasma wood or dried fine powder of picrasma wood, etc., and the compound expressed by formula II is a novel substance and obtained easily by reducing a compound expressed by formula III isolated simultaneously from the picrasma wood by the usual method, etc. The above-mentioned xanthine oxidase inhibitor is capable of suppressing the formation of uric acid to improve hyperuicemia, and useful as a preventing and treating agent for gout, calculus in urinary organ systems.