Anticancer activity of free gamma-linolenic acid on AH-109A rat hepatoma cells and the effect of serum albumin on anticancer activity of gamma-linolenic acid in vitro.

The cytotoxicity of gamma-linolenic acid (C18:3n-6) against rat hepatoma AH-109A cells and the effect of bovine serum albumin (BSA) on its toxicity were examined in culture. The proliferation of AH-109A cells, evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, was significantly suppressed by gamma-linolenic acid above 5 micrograms/ml concentration in serum-free culture medium. However, its toxicity was reduced by supplement of BSA. Similar observation of reduced toxicity by BSA was shown by the method of trypan blue dye exclusion and a colony formation assay. The cytotoxicity of gamma-linolenic acid was correlated closely with the concentration of unbound (free) gamma-linolenic acid. Production of thiobarbituric acid reactive material, one of the indicators of lipid peroxidation, was stimulated by gamma-linolenic acid and inhibited by BSA. These results suggested that the presence of albumin suppressed the cytotoxicity of the free fatty acid.