Inhibition of protein synthesis in ehrlich ascites-tumour cells by the phenanthrene alkaloids tylophorine, tylocrebrine and cryptopleurine

The phenanthroindolizidine alkaloids tylophorine and tylocrebrine and the phenanthroquinolizidine alkaloid cryptopleurine inhibit incorporation of leucine into protein in Ehrlich ascites-tumour cells by 50% at 1 × 10 −6 M, 2 × 10 −7 M, and 2 × 10 −8 M respectively, but do not inhibit incorporation of uracil into nucleic acids at 10 −5 M. Cryptopleurine inhibits leucine incorporation into protein in a cell-free system from Ehrlich cells, but at 10 −5 M does not inhibit protein synthesis in Escherichia coli.