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

Abstract 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 .