Ascidiathiazones A (3) and B (4), two new tricyclic thiazine-containing quinolinequinone alkaloids, were isolated from
the New Zealand ascidian Aplidium species. Both compounds inhibited the in Vitro production of superoxide by PMAstimulated human neutrophils in a dose-dependent manner with IC50 1.55 ( 0.32 and 0.44 ( 0.09 íM, respectively. In
ViVo inhibition of superoxide production by peritoneal neutrophils in a murine model of gout was observed for both
compounds with oral doses of 25.6 ímol/kg. Ascidiathiazone A (3) was synthesized in four steps from 8-hydroxyquinoline-
2-carboxylic acid.