Oral sulforaphane increases Phase II antioxidant enzymes in the human upper airway.
BACKGROUND
Cellular oxidative stress is an important factor in asthma and is thought to be the principle mechanism by which oxidant pollutants such as ozone and particulates mediate their pro-inflammatory effects. Endogenous Phase II enzymes abrogate oxidative stress through the scavenging of reactive oxygen species and metabolism of reactive chemicals.


OBJECTIVE
We conducted a placebo-controlled dose escalation trial to investigate the in vivo effects of sulforaphane, a naturally occurring potent inducer of Phase II enzymes, on the expression of glutathione-s-transferase M1 (GSTM1), glutathione-s-transferase P1 (GSTP1), NADPH quinone oxidoreductase (NQO1), and hemoxygenase-1 (HO-1) in the upper airway of human subjects.


METHODS
Study subjects consumed oral sulforaphane doses contained in a standardized broccoli sprout homogenate (BSH). RNA expression for selected Phase II enzymes was measured in nasal lavage cells by RT-PCR before and after sulforaphane dosing.


RESULTS
All subjects tolerated oral sulforaphane dosing without significant adverse events. Increased Phase II enzyme expression in nasal lavage cells occurred in a dose-dependent manner with maximal enzyme induction observed at the highest dose of 200 g broccoli sprouts prepared as BSH. Significant increases were seen in all sentinel Phase II enzymes RNA expression compared to baseline. Phase II enzyme induction was not seen with ingestion of non-sulforaphane containing alfalfa sprouts.


CONCLUSIONS
Oral sulforaphane safely and effectively induces mucosal Phase II enzyme expression in the upper airway of human subjects. This study demonstrates the potential of antioxidant Phase II enzymes induction in the human airway as a strategy to reduce the inflammatory effects of oxidative stress.


CONCLUSIONS
This study demonstrates the potential of enhancement of Phase II enzyme expression as a novel therapeutic strategy for oxidant induced airway disease.


CONCLUSIONS
A placebo-controlled dose escalation trial demonstrated that naturally occurring sulforaphane from broccoli sprouts can induce a potent increase in antioxidant Phase II enzymes in airway cells.
Riedl
Marc A
MA
The Hart and Louis Laboratory, Clinical Immunology and Allergy, Department of Medicine, UCLA David Geffen School of Medicine, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA. mriedl@mednet.ucla.edu
Saxon
Andrew
A
Diaz-Sanchez
David
D
D000284:Administration, Oral; D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D001937:Brassica / Q000737:chemistry; D004798:Enzymes / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005961:Glucosinolates / Q000097:blood; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017879:Isothiocyanates / Q000097:blood; D008297:Male; D008875:Middle Aged; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism; D009305:Nasopharynx / Q000187:drug effects* / Q000201:enzymology; D013454:Sulfoxides; D013861:Thiocyanates / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D015854:Up-Regulation; D055815:Young Adult
D000975:Antioxidants; D004798:Enzymes; D005961:Glucosinolates; D017879:Isothiocyanates; D013454:Sulfoxides; D013861:Thiocyanates; C037152:isothiocyanic acid; D051547:Heme Oxygenase-1; D016660:NAD(P)H Dehydrogenase (Quinone); D005982:Glutathione Transferase; C016766:sulforaphane