Inhibitory effect of unicellular green algae ( Chlorella vulgaris ) water extract on allergic immune response

Background Chlorella is used as a functional food in East Asia and has been shown to enhance immune system function. However, there has been no direct evidence of the suppressive effect of a hot water extract of Chlorella vulgaris ( CVE ) on histamine‐mediated allergic responses . Results The antihistamine activity of CVE was analysed using rat peritoneal mast cells ( RPMCs ) stimulated by compound 48/80. For in vivo verification, ovalbumin ( OVA )‐immunised BALB /c mice were treated with CVE orally. Serum immunoglobulin E ( IgE ) levels and splenocyte cytokine levels were determined by enzyme‐linked immunosorbent assay ( ELISA ). CVE prevented histamine release through degranulation of mast cells by blocking the uptake of extracellular Ca 2+ into RPMCs . Moreover, CVE administration inhibited serum IgE overproduction by OVA via induction of T helper 1 (Th1) skewing that was dependent on interferon‐ γ ( IFN ‐ γ ) and interleukin 12 ( IL ‐12) secretion . Conclusion The results of this study clearly demonstrate that CVE acts as an antiallergic dietary agent by suppressing histamine release via its enhancive effect on Th1‐related responses. © 2013 Society of Chemical Industry