Biosynthesis of the Bufadienolide Ring of Scillirosid in Scilla maritima

Abstract
Administration of sodium [1,2-14C2]oxaloacetate and sodium [1-14C]acetate to S. maritima plants yielded labeled scillirosid. A systematic degradation of scillirosid indicated that the .alpha.-pyrone ring of the bufadienolide is formed by the condensation of a pregnane derivative (derived from mevalonic acid via squalene) and 1 molecule of oxaloacetic acid.