Cyanidin-3-glucoside suppresses Th2 cytokines and GATA-3 transcription factor in EL-4 T cells.

Allergic disease is dominated by Th2 immune responses. Interleukin (IL)-4 and IL-13, representative Th2 cytokines, play pivotal roles in the pathogenic activation of the Th2 immune response. In this study, we found that cyanidin-3-glucoside chloride (C3G), an anthocyanin suppressed IL-4 and IL-13 produced in activated EL-4 T cells but not Th1 cytokines including IL-2, interferon-γ, or IL-12. IL-4 and IL-13 mRNA levels and luciferase activation in cells transiently transfected with IL-4 and IL-13 promoter reporter plasmids were significantly inhibited by C3G, suggesting that suppression might be, at least in part, regulated at the transcriptional level. Data from western blot and reverse transcription-polymerase chain reaction analyses of transcription factors involved in cytokine expression suggested that expression of GATA-3, but not T-bet, was downregulated in the nucleus by C3G. Taken together, our data indicate that C3G may has potential as an anti-allergic agent suppressing Th2 activation by downregulating Th2 cytokines and the GATA3 transcription factor in allergies.