RESUMO
Several derivatives of well-known natural anticancer drugs have been synthesized and will continue to be, to overcome their delivering problems, or effectiveness. Characteristics such as poor solubility, metabolic inactivation, resistance development, rapid clearance or short half-life, adverse side effects like nausea, alopecia, anorexia are common undesirable limitations to their clinical use. Drug toxicity to less sensitive tumors as those in liver or brain is another aimed goal. Recent efforts to reverse undesirable physicochemical properties of well-established natural anticancer compounds are focused. Improved antitumor action of olivacine in L(1210) leukemia with slightly soluble halides with increased life span as well as "cured" animals was observed.