The Biological Effects Of L-4-Flhorophenyl Alanin And Other 5 Kinds Of Amino Acid Derivatives

Amino acids and their derivatives have important biological activities, and more and more pharmaceutical reserchers modify amino acids, and enhance the activities of amino acids. Amino acids play important roles in material metabolism and genetic information transfer. L-phenylalanine (L-Phe) is one kind of aromatic amino acids with physiological activity, an intermediate of many anti-cancer drugs, and therefore essential for human and animals. The study synthesized L-4-bromophenyl alanine, L-4-iodine phenylalanine, L-4-sulfonic acid phenylalanine and other amino acid derivatives based on adding halogen element into the molecular of phenylalanine, purchased L-4-fluorophenyl alanine and L-4-chlorobenzene, and then studied their biological activities.Human liver cancer cell BEL-7402 in logarithmic phase were cultured with medium added into L-4-fluorophenyl alanine, L-4-chlorophenyl alanine, L-4-bromophenyl alanine, L-4-iodine phenylalanine, L-4-sulfonic acid phenylalanine, and L-alanine sulfonic at the concentrations of 6, 3, 1.5, 0.75 mmol/L, 3 ,1.5 ,0.75, 0.375 mmol/L, 3, 1.5, 0.75,0.375mmol/L, 3, 1.5, 0.75, 0.375mmol/L, 130, 65, 32.5, 16.25 mmol/L, and 100, 50, 25, 12.5 mmol/L, respectively, and the cells without the drug were considered as control group. The following methods were applied to study the effect of above amion acids derivatives on BEL-7402 (1) Morphology of living cells (2) MTT method (3) Cell count method (4) Hoechst33258 staining (5) Soft-agar diffusion method.MTT and cell count results showed that the amino acid derivatives had inhibitory effect on BEL-7402 and the inhibitory role had a positive correlation with concentration and time. When BEL-7402 cultured with above amino acid derivatives at the concentration of 3mmol/L, some cells became small and round, adherent ability decreased significantly, and cell gap enlarged at 24h. While with 10mmol/L of above amino acid derivatives, the majority of cells were killed after 24h. Therefore, we chose concentration of 3mmol / L to carry out Hoechst33258 staining and soft agar diffusion experiments. Hoechst33258 staining results showed that other 5 kinds of amino acid derivatives can promote apoptosis except L-cysteic acid in the concentration of 3mmol/L. The degrees of malignant proliferation of cells in the concentration of 3mmol/L measeured by soft-agar diffusion method were as follows: control group> L-cysteic Acid> L-4-sulfonic acid phenylalanine> L-4-iodine phenylalanine> L-4-bromophenyl alanine> L-4-chlorophenyl alanine> L-4-fluorophenyl alanine, while the toxicities of above amino acid derivatives were in sequence as follows: L-4-fluorophenyl alanine> L-4-chlorophenyl alanine> L-4-bromophenyl alanine> L-4-iodine phenylalanine> L-4-sulfonic acid phenylalanine > L-cysteic Acid.It was founded that amino acid derivatives can inhibit the proliferation of BEL-7402, and inhibition rate had a ponsitive corelation with time and concentration. Moreover, the inhibitory role of amino acid derivatives to the growth of BEL-7402 may be related to the apoptosis of cells, which needs further study to confirm their relationship with cell apoptosis. It was concluded that L-phenylalanine derivatives may be a potential drug for the treatment of liver cancer.