Aim of the study: Soybeans are known to stimulate food allergies; however, current therapies are lacking in alleviating hypersensitivity. The present study investigated whether Forsythia suspensa extract could attenuate purified soybean -conglycinin-induced anaphylactic reactions in weaned piglets.

Materials and methods: Eighteen 14-day-old piglets were sensitized and boosted by oral administration of purified -conglycinin. Forsythia suspensa extract was supplemented in the diet after the initial sensitization and continued for the remainder of the experiment. Piglets were challenged on day 28, and anaphylactic symptoms, passive cutaneous anaphylaxis, plasma histamine and intestinal microbial flora were analyzed. T-cell proliferative responses and cytokine production were also determined.

Results: Forsythia suspensa extract alleviated -conglycinin-induced anaphylactic symptoms by markedly reducing anaphylactic antibodies, mast cell degranulation, and histamine release while improving intestinal microbial flora. Furthermore, Forsythia suspensa extract significantly suppressed-conglycinininduced T lymphocyte proliferation and IL-4 synthesis.

Conclusion: Forsythia suspensa extract protected -conglycinin-sensitized piglets from anaphylactic reactions. Forsythia suspensa extract may provide a novel effective therapy for soybean allergy.