Chinese herbal extracts of Rubia cordifolia and Dianthus superbus suppress IgE production and prevent peanut-induced anaphylaxis

BACKGROUND: Peanut allergy is characterized by increased levels of peanut-specific IgE in the serum of most patients. Thus, the most logical therapy would be to inhibit the IgE production by committed B-cells. This study aims to investigate the unreported anti-IgE effects of Chinese herbal extracts of Rubia cordifolia (Qiancao) and Dianthus superbus (Qumai). METHODS: Seventy herbal extracts were tested for their ability to reduce IgE secretion by a human B-cell line. Those with the lowest inhibitory concentration 50 (IC(50)) values were tested in a mouse model of peanut-anaphylaxis. Anaphylactic scores, body temperature, plasma histamine and peanut-specific-immunoglobulins were determined. RESULTS: Rubia cordifolia and Dianthus superbus inhibited the in vitro IgE production by a human B-cell line in a dose-dependent manner and the in vivo IgE production in a murine model of peanut allergy without affecting peanut-specific-IgG1 levels. After challenge, all mice in the sham groups developed anaphylactic reactions and increased plasma histamine levels. The extract-treated mice demonstrated significantly reduced peanut-triggered anaphylactic reactions and plasma histamine levels. CONCLUSION: The extracts of Rubia cordifolia and Dianthus superbus inhibited the IgE production in vivo and in vitro as well as reduced anaphylactic reactions in peanut-allergic mice, suggesting potentials for allergy treatments.