Cinnamaldehyde Altered Cellular Immune Responses of Tongue Sole (Cynoglossus semilaevis) In Vitro

Cinnamaldehyde, a liposoluble extract from cinnamon, is a natural compound with immunity enhancement efficacy on terrestrial animals. However, its immunoregulation effects on aquatic animals has rarely been investigated due to its poor water solubility and easy oxidability. Thus, cinnamaldehyde micro emulsion (CME) was prepared to overcome these limitations. Phagocytic, respiratory burst, bactericidal, and proliferative activity of Cynoglossus semilaevis leukocytes stimulated by CME were evaluated in vitro. Leukocytes were incubated with 0, 1, 10, 100 and 1000 μg/ml cinnamaldehyde or 100 μg/ml lipopolysaccharide. Results showed that cinnamaldehyde affected leukocytes phagocytic, respiratory burst, bactericidal and proliferative activity significantly. In conclusion, low doses of cinnamaldehyde (1, 10 μg/ml) exhibited significantly high bactericidal activity, while high doses (100, 1000 μg/ml) inhibited cellular immunity of C. semilaevis.