Broccosprout extract inhibits the nasal allergic response to diesel exhaust particles in atopic individuals

Abstract

Oxidant stress is a factor in the development of allergic sensitization and asthma by triggering an inflammatory response. Well‐characterized Diesel Exhaust Particles (DEP) collected from the emissions of a diesel engine have been shown in vitro, in animals and human to induce inflammatory and pro‐allergic effects that can be abrogated by antioxidants. Sulforaphane (SFN) is a naturally occurring isothiocyanate in broccoli that is a potent inducer of phase II enzymes and antioxidant response via activation of Nrf2. A strain of broccoli sprout extract (BSE) (Broccosprout®) with consistently high levels of SFN glucosinolate was obtained from Johns Hopkins University. To test the hypothesis that BSE could inhibit the inflammatory response caused by DEP, 29 subjects who responded to DEP challenge underwent 4 weeks of washout, followed by daily BSE administered as a single oral AM dose (containing >100 μmol/g SFN diluted with mango juice) for four days. The DEP challenge was carried out before and after BSE consumption. After DEP exposure the average cell count increased 4.5‐fold (p<0.0005) at 24 hours, but after four days of oral BSE administration, there was no significant increase in cell number after DEP (83.9±90.7%; p=0.389). The effects of BSE on a panel of cytokines in the nasal washes are being evaluated. These studies provide a model in which preventive and therapeutic strategies targeting asthma and allergic diseases can be developed based on the inhibition of oxidant stress through the action of phytochemicals such as SFN. Research Supported by the UCLA Asthma Center NIH Grant No. 1 U19‐AI 070453