Genotoxic effects of Karwinskia humboldtiana toxin T-514 in peripheral blood lymphocytes.

Toxicity by Karwinskia humboldtiana, a Rhamnaceae plant, has been assessed in a number of studies. Four dimmeric anthracenones, named T-496, T-514, T-516 and T-544 for their molecular weight, have been isolated from this plant. T-514, in particular, has been shown to be toxic to liver and lung as well as to tumoral cell lines, preferentially to those from liver tumors. For this reason it has been suggested that the toxin could be used as an antineoplastic agent. The present study was performed to characterize the biological activity of T-514 as a potential cytostatic and genotoxic agent. Peripheral blood lymphocytes in culture were used as a test system, where chromosomal aberrations and sister chromatid exchanges were scored in order to evaluate genotoxicity, and mitotic index and cell proliferation kinetics were used as parameters for cytostatic and cytotoxic ability. Genotoxicity to lymphocytes was negative. However, proliferation was affected by the toxin, demonstrating a cytostatic activity independent of genotoxic damage.