Toxicarioside B and toxicarioside C. New cardenolides isolated from Antiaris toxicaria latex-derived dart poison

Bioassay-guided fractionation of the chloroform/methanol extract of a dart poison from Indonesian Borneo (Kalimantan), derived from Antiaris toxicaria latex, has led to the isolation of two new cardenolides, toxicarioside B [2] and toxicarioside C [3]. Structures for 2 and 3 were deduced by analysis of spectroscopic data; these materials are isomeric with toxicarioside A [1] previously isolated in our earlier work with the same poison. The bioassay employed to isolate cardenolides 2 and 3 involves inhibition of Na+/K+-ATPase and mimics the suspected mode of action of these ''cardiac-glycoside'' toxins. (C) 1997 Elsevier Science Ltd.