Up-regulation of cytochrome P450 and phase II enzyme systems in rat precision-cut rat lung slices by the intact glucosinolates, glucoraphanin and glucoerucin.
It is believed that the chemopreventive activity of cruciferous vegetables in the lung and other tissues is exclusively the result of exposure to degradation products of glucosinolates, such as the isothiocyanates, and that the parent glucosinolates make no contribution. In the present study, evidence is presented for the first time that, in rat lung, the intact glucosinolates, glucoraphanin and glucoerucin, can modulate carcinogen-metabolising enzyme systems. The glucosinolates were isolated from cruciferous vegetables and incubated (1-25 μM) with precision-cut rat lung slices for 24h. Both glucosinolates, at concentrations as low as 1 μM, up-regulated the O-deethylation of ethoxyresorufin and the apoprotein levels of CYP1A1 and CYP1B1; supplementation of the incubation medium with myrosinase, the enzyme that converts glucosinolates to their corresponding isothiocyanates, abolished the rise in ethoxyresorufin O-deethylase activity. In contrast, neither glucosinolate, at the concentrations studied, influenced quinone reductase activity in the lung slices, but addition of myrosinase to the glucosinolate incubations led to a marked rise in activity. Glutathione S-transferase activity, monitored using 1-chloro-2,4-dinitrobenzene as the accepting substrate, was elevated in lung slices exposed to glucoraphanin. GSTα protein levels were increased by glucoraphanin and, to a much lesser extent, glucoerucin. It may be concluded that intact glucosinolates can modulate the activity of pulmonary carcinogen-metabolising enzyme systems, and can thus contribute to the documented chemopreventive activity of cruciferous vegetables in the lung.
Abdull Razis
Ahmad Faizal
AF
Molecular Toxicology Group, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK.
Bagatta
Manuela
M
De Nicola
Gina Rosalinda
GR
Iori
Renato
R
Ioannides
Costas
C
D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003640:Dealkylation / Q000187:drug effects; D005947:Glucose / Q000031:analogs & derivatives* / Q000494:pharmacology; D005961:Glucosinolates / Q000494:pharmacology*; D005978:Glutathione / Q000032:analysis; D005982:Glutathione Transferase / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D007096:Imidoesters / Q000494:pharmacology*; D066298:In Vitro Techniques; D017879:Isothiocyanates; D008168:Lung / Q000187:drug effects / Q000201:enzymology; D008297:Male; D050217:Metabolic Detoxication, Phase II / Q000502:physiology*; D010078:Oxazines / Q000378:metabolism; D010091:Oximes; D051381:Rats; D017208:Rats, Wistar; D013440:Sulfides / Q000494:pharmacology; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects*
D016588:Anticarcinogenic Agents; D005961:Glucosinolates; D007096:Imidoesters; D017879:Isothiocyanates; D010078:Oxazines; D010091:Oximes; D013440:Sulfides; D013454:Sulfoxides; D013861:Thiocyanates; C119493:glucoerucin; C007649:ethoxyresorufin; D003577:Cytochrome P-450 Enzyme System; C073539:erucin; D005982:Glutathione Transferase; D006026:Glycoside Hydrolases; C022739:thioglucosidase; C016766:sulforaphane; D005978:Glutathione; D005947:Glucose; C119494:glucoraphanin