PRESENCE IN PIERIS-RAPAE OF CYTOTOXIC ACTIVITY AGAINST HUMAN CARCINOMA-CELLS

Cytotoxic activity in extracts of pupae and adults of various kinds of butterflies and moths was tested in vitro against the human gastric c arcinoma cell line, TMK-1, which was chosen as an example of human car cinoma cells. Among the species examined, cytotoxicity was limited to Pieris rapae, Pieris napi and Pieris brassicae. Activity was found dow n to a dilution of 1/10(4), while with the other butterflies and moths no activity was observed, even at 1/10(2). When the cytotoxicity of t he three developmental stages, larvae, pupae and adults, of Pieris rap ae was compared, the pupae showed the strongest activity, the IC50 aga inst TMK-1 cells being at the 1/10(6) dilution. For larvae and adults, the respective IC50 values were at the 1/10(5) and 5/10(5) dilutions. The active principle in the pupae of Pieris rapae was found to be hea t-labile and not extractable with organic solvents, but precipitated w ith ammonium sulfate and digested by proteases, suggesting that it is a protein. This cytotoxic factor was named pierisin.