Suppressive effect of ethanol extract from passion fruit seeds on IgE production

- Ethanol extract from passion fruit seeds (PFS) suppressed IgE production by U266 cells.
- The IgE production-suppressive effect was caused by downregulated IgE gene expression.
- PFS selectively suppressed IgE production by mouse splenocytes.
- Resveratrol and piceatannol were suggested as bioactive ingredients in PFS.
- PFS, resveratrol, and piceatannol showed the effect in vivo after oral administration.

An array of foodstuffs was screened for the suppressive effect on production of IgE, a key molecule in the type I allergic reaction, using U266 cells. An ethanol extract from passion fruit seeds (PFS) has emerged as a food material with the IgE production-suppressive effect as the result of screening. Real-time RT-PCR analysis revealed that the IgE production-suppressive effect was caused by downregulated IgE gene expression. In addition, PFS selectively suppressed IgE production and did not affect the production of IgG, IgA, or IgM by mouse splenocytes. Resveratrol and piceatannol were identified as bioactive ingredients contained in passion fruit seeds. The effect of oral administration of PFS, resveratrol, and piceatannol was evaluated using a mouse model of allergic contact dermatitis. Both stilbenoids significantly suppressed IgE production in orally administered mice. Overall results indicated that passion fruit seeds are a promising candidate with the antiallergy effect for development of functional foods.