As the American Botanical Council has found, in some herbal extracts the ethanol method is superior while in others it is the aqueous method that obtains the best results. Oleander is one of those where the aqueous method obtains a far superior product. The patented medicine Anvirzel, the home remedy "oleander soup" and the herbal supplement Sutherlandia OPC are all made using essentially the same aqueous extraction method. Anvirzel is freeze dried and re-constituted for use, whereas the other two use alcohol strictly as a preservative (and in the "oleander soup", vinegar is often substituted and sometimes colloidal silver as preservatives).
Oleander contains a great many compounds that are believed by researchers to work synergistically to make it as effective as it is against cancer, hep-c, HIV/AIDS and other conditions. Some of these compounds are polar compounds (water soluable), such as the long-chain polysacharrides that many feel play a vital part, while others are non-polar (non-water soluable), such as the cardiac glycosides which cross assay with digoxin/digatalis (including the main active ingredient, oleandrin). When you use an ethanol extraction method you get more of the non-polar compounds but the polar compounds tend to precipitate out. With the aqueous extraction method you get both.
An ethanol extraction of oleander which is used in Russia for heart conditions and vertigo was relabeled and passed off as a competitor to the patended aqueous extraction medicine Anvirzel by a fake Biotech company in recent years with tragic results. One patient who was a good internet friend of mine was convinced to switch to the ethanol extract and his tumors returned and he ultimately died. He tried virtually every protocol and form of medicine you could imagine. Of all the things he tried, only Anvirzel made his tumors shrink and disappear (he had non-small cell lung cancer) and he stubbornly refused to believe that he had been duped by unscrupulous parties.
A new version of oleander is currently being tested at MD Anderson which uses yet another extraction method: liquid carbon dioxide and micro-fine particles of oleander. It is believed to be the most potent of the oleander extracts yet when it comes to cancer - though it will likely be years before it becomes available.