The effects of Brassica oleraceae var capitata on epidermal glutathione and lipid peroxides in DMBA-initiated-TPA-promoted mice.
BACKGROUND
The objective of the present study was to determine if modulation of GSH-dependent antioxidant protective system by Brassica oleraceae var capitata might inhibit the molecular mechanism of skin tumor promotion.


METHODS
In a two stages skin carcinogenesis model, the protocol used included a single topical application of 200 nmol of the initiator 7,12-dimethyl-benz(a) anthracene (DMBA) to the backs of mice, followed 1 week later by promotion with 10 nmol of 12-O-tetradecanoyl-phorbol-13 acetate (TPA) twice weekly for 30 weeks. In addition to this regimen, 0.1 g/L brassica extract was added water week prior to the initiating dose of DMBA in the treatment group. Tissue glutathione (GSH) contents and levels of lipid peroxidation products (measured as thiobarbituric-acid (TBA)-reactive substances) were quantitated in the skin tumors generated by the initiation-promotion protocol.


RESULTS
It was observed that the tumor incidence and tumor multiplicity in the treatment group was highly significantly low compared to the first group of mice (p < 0.001 and p < 0.001, respectively). In the treatment group, GSH content in the papillomas was higher than in the non-involved skin surrounding the papillomas.


CONCLUSIONS
We suggest that the anticarcinogenicity of Brassica may be linked to its ability to facilitate or enhance the activity of the natural GSH-dependent antioxidant protective system of the epidermal cells during the later stages of skin tumor promotion.
Isbir
T
T
University of Istanbul, Department of Molecular Medicine, Turkey. tisbir@superonline.com
Yaylim
I
I
Aydin
M
M
Oztürk
O
O
Koyuncu
H
H
Zeybek
U
U
Ağaçhan
B
B
Yilmaz
H
H
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D016588:Anticarcinogenic Agents / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D001937:Brassica / Q000737:chemistry*; D002273:Carcinogens; D003043:Cocarcinogenesis; D004817:Epidermis / Q000187:drug effects* / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D015227:Lipid Peroxidation; D051379:Mice; D018384:Oxidative Stress; D010212:Papilloma / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013755:Tetradecanoylphorbol Acetate
D016588:Anticarcinogenic Agents; D000975:Antioxidants; D002273:Carcinogens; D010936:Plant Extracts; D015127:9,10-Dimethyl-1,2-benzanthracene; D005978:Glutathione; D013755:Tetradecanoylphorbol Acetate