“…These inhibitors include, e.g., pyrogallol and its derivatives, catechol, tropolones, and 3,4-dihydroxy-2-methylpropiophe none (U-0521). Although they appeared to be effec tive, they had poor bioavailability and were usually extremely short acting (Belleau and Burba, 1961;Dorris and Dill, 1977;Ross and Haljasmaa, 1964a). Gallates, catechols, tropolone and its derivatives, and pyrogallol were all tested in vitro and in vivo.…”