Effect of garlic on lipid peroxidation and antioxidation enzymes in DMBA-induced skin carcinoma.
OBJECTIVE
Naturally occurring phytochemicals display an active cancer preventive strategy to inhibit, delay, or reverse human carcinogenesis. Studies have indicated that certain daily-consumed dietary phytochemicals have cancer protective effects mediated by carcinogens. Lipid peroxide plays a detrimental role in all cancers including skin carcinogenesis. Garlic, a phytochemical, has acquired a special position in the folklore of many cultures as a formidable prophylactic and therapeutic medicinal agent. In this report, we pursue the chemopreventive effect of aqueous garlic on skin carcinogenesis.


METHODS
"Swiss albino mice" were divided into five groups depending on the combination of skin cancer-inducing 7,12-dimethylbenz[a]anthracene and garlic treatments. Histology of the affected skin and biochemical assays for lipid peroxide, catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase were performed to demonstrate the effect of garlic in mice. Immunoblotting was performed with cyclo-oxygenase-2, p53, and caspase-3 to demonstrate expressions of the respective proteins in skin lysates.


RESULTS
Garlic extracts inhibited the oxidative modification of lipids, thus protecting cells from injury by the oxidized molecules. The best chemopreventive action of garlic was observed in mice in which garlic treatment was performed before and after the induction of skin carcinogenesis. Garlic ingestion delayed formation of skin papillomas in animals and simultaneously decreased the size and number of papillomas, which was also reflected in the skin histology of the mice treated.


CONCLUSIONS
The protective effects against skin cancer elicited by garlic in mice are believed to be due at least in part to the induction cellular defense systems.
Das
Ila
I
Departments of Cancer Chemoprevention and Cancer Detection and Screening, Chittaranjan National Cancer Institute, Kolkata, India.
Saha
Tapas
T
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000009:adverse effects; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use*; D000975:Antioxidants / Q000378:metabolism*; D001551:Benz(a)Anthracenes; D015415:Biomarkers / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens; D053148:Caspase 3 / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D005260:Female; D005737:Garlic; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D051379:Mice; D010212:Papilloma / Q000188:drug therapy; D010936:Plant Extracts / Q000494:pharmacology*; D012867:Skin / Q000033:anatomy & histology / Q000187:drug effects*; D012878:Skin Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D001551:Benz(a)Anthracenes; D015415:Biomarkers; D002273:Carcinogens; D010936:Plant Extracts; D016159:Tumor Suppressor Protein p53; C046810:7,12-dihydroxymethylbenz(a)anthracene; D015127:9,10-Dimethyl-1,2-benzanthracene; D051546:Cyclooxygenase 2; D053148:Caspase 3