Bussein is shown to be a mixture of bussein A, C44H56018, and bussein B, C,,H,O,, ; structure (Ia) is proposed for bussein A and structure (Ib) for bussein B.caudatum Sprague,l and has been concluded to contain, among others, three acetyl, one isobutyryl, and one 2-methylbutyryl g r o u ~s . ~, ~We have found that bussein is a mixture of two components, i.e. bussein A, C,H,,O,,, and bussein B, C4,HM01,, to which structures (Ia) and (Ib), respectively, are assigned. The mass spectrum of a crystalline sample, BUSSEIN is a crystalline compound isolated from the timber of Entandrophragma bussei Harms. and Entandrophragma 1964, 322.