It is my understanding that over 500 compounds have been identified in oleander so far (though that surely seems like a huge number). Among the recognizable immune boosters and cancer fighters are:
Oleandrin and a number of other cardiac glycosides such as Oleandrinogen, Oleandrin, Oleandrigenin; several long-chain polysacharrides such as Beta-sistosterol; Quercitin, Linoleic-acid, Oleic-acid, Adynerin, Alpha-amyrin, Betulin, Foliandrin, Folinerin, Gitoxigenin, Isoquercitrin, Lauric-acid, Neriin, Oleanolic-acid, Rutin, Stigmasterol, Ursolic-acid, Uzarigenin.