| Summary: | Tormentic acid and euscaphic acid were isolated from plant material and transformed into amides holding an extra rhodamine B moiety; these compounds were screened for their cytotoxic activity employing a panel of human tumor cell lines and non-malignant fibroblasts. Prerequisites for both high cytotoxicity and tumor cell selectivity seem to be the combination of an amide (from a secondary amine but not from a primary), the use of homopiperazine rather than piperazine as a spacer together with rhodamine B (as a cationic center) and – most important-a triterpene holding a (2α, 3β) configuration of the substituents in ring A of the triterpenoid skeleton. All these features are found in tormentic acid derived compound 15; it acts as a mitocan; it is approximately 190 times more cytotoxic for ovarian carcinoma cells than for non-malignant fibroblasts, and 15 displayed an EC50 as low as 1 nM for several human cancer cell lines.
|
|---|