Turbinaric acid is a moderately cytotoxic squalene carboxylic acid isolated from brown algae (Turbinaria ornata).

Methods: Peripheral blood mononuclear cells containing NK cells were isolated and cocultured with target K562 cells at three different effector-to-target (E:T) ratios of 50:1, 25:1, and 12.5:1. Prednisolone hemisuccinate or IVIG were then added to the tubes at an E:T ratio of 50:1 to assess the inhibitory effect. Percent killing was recorded and statistically analyzed using the Student t test.
Results: In experiments with an E:T ratio of 50:1 and either Prednisolone hemisuccinate or IVIG in the coculture, the mean target cell killing rate was 26.4%. In cultures using the same E:T ratio, this killing rate was significantly reduced in the presence of IVIG (9.9%) or Prednisolone hemisuccinate (13.6%) (P < 0.001 for both analyses). Prednisolone hemisuccinate was able to inhibit the cytolytic activity of NK cells. [1]