Ferulic acid enhances IgE binding to peanut allergens in Western blots

Ferulic acid, a phenolic compound, is known to complex with proteins and peanut allergens. Preliminary studies indicated that ferulic acid could also complex with and inhibit IgE antibodies to peanut allergens in ELISA. However, results from Western blots were quite different. The objective of this study was to report the unexpected finding of IgE binding being enhanced rather than reduced by ferulic acid in Western blot. Ferulic acid, at various concentrations (0–10 mg/ml), was mixed with a pooled plasma (containing IgE antibodies) from peanut-allergic individuals before incubation with a peanut allergen-bound membrane and colorimetric detection of IgE. Results showed that an enhancement of allergen bands or IgE binding, compared to the control, was observed at a ferulic concentration of 10 mg/ml. Compounds with a similar structure, such as caffeic acid and chlorogenic acid, at the same concentration, did not have an enhancing effect on IgE binding. Tests with ferulic acid alone or soy proteins indicated that the enhanced IgE binding was due to the IgE–ferulic complexes and not ferulic acid itself. It was concluded that ferulic acid (10 mg/ml), in combination with IgE, enhanced IgE binding to peanut allergens in Western blots. The finding indicated that ferulic acid can help reduce the time for colour development of protein bands in Western blots.