Prenylated flavanone derivatives isolated from Erythrina addisoniae are potent inducers of apoptotic cell death

NoExtracts of Erythrina addisoniae are frequently used in the traditional medicine of Western Africa, but insufficient information about active compounds is available. From the stem bark of E. addisoniae, three (1, 2, 4) and three known (3, 5, 6) flavanones were isolated: addisoniaflavanones I and II, containing either a 2″,3″-epoxyprenyl moiety (1) or a 2″,3″-dihydroxyprenyl moiety (2) were shown to be highly toxic (MTT assay: EC50 values of 5.25 ± 0.7 and 8.5 ± 1.3 μM, respectively) to H4IIE hepatoma cells. The cytotoxic potential of the other isolated flavanones was weaker (range of EC50 values between 15 and >100 μM). Toxic effects of addisoniaflavanone I and II were detectable after 3 h (MTT assay). Both compounds induced an apoptotic cell death (caspase-3/7 activation, nuclear fragmentation) in the hepatoma cells and, at high concentrations, also necrosis (membrane disruption: ethidium bromide staining). Formation of DNA strand breaks was not detectable after incubation with these compounds (comet assay). In conclusion, the prenylated flavanones addisoniaflavanones I and II may be of interest for pharmacological purposes due to their high cytotoxic and pro-apoptotic potential against hepatoma cells