Cytotoxicity of cinnamic aldehyde on leukemia L1210 cells

Cytotoxic effect of cinnamic aldehyde (CA) on L1210 mouse leukemia cells was tested. Addition of CA in Fischer's medium at 4.8 micrograms/ml could inhibit the growth of L1210 by 50 per cent. The terminal aldehyde-group of CA molecule was found to be responsible to the inhibition. Experiments of incorporating [3H]-uridine, [3H]-thymidine, and [3H]-leucine by the cells revealed that the syntheses of protein, DNA, and RNA were suppressed by the presence of CA in the culture solution with potency appeared in that order. The inhibitory effect of CA on glycolysis was insignificant. Direct reaction between aldehyde-groups of CA molecules and sulfhydryl-groups of cell components was proved. The results suggested that CA inhibited L1210 cells by blocking protein synthesis through trapping sulfhydryl-containing amino acids in the cell.