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Published on: October 16, 2010
Garlic and associated allyl sulfur components inhibit N-methyl-N-nitrosourea induced rat mammary carcinogenesis
E M Schaffer1, J Z Liu, J Green
1Department of Nutrition, The Pennsylvania State University, University Park 16802, USA.
Abstract:
Our previous studies demonstrated that dietary garlic powder supplementation inhibits N-nitrosamine induced DNA alkylation in liver and mammary tissue. The present studies compared the impact of dietary supplementation with garlic powder or two garlic constituents, water-soluble S-allyl cysteine (SAC) and oil-soluble diallyl disulfide (DADS), on the incidence of mammary tumorigenesis induced by N-methyl-N-nitrosourea (MNU). Female Sprague-Dawley rats were fed semi-purified casein based diets with or without supplements of garlic powder(20g/kg), SAC (57 micromol/kg) or DADS (57 micromol/kg) for 2 weeks prior to treatment with MNU (15 mg/kg body wt). Garlic powder, SAC and DADS supplementation significantly delayed the onset of mammary tumors compared to rats receiving the unsupplemented diet. Tumor incidence 23 weeks after MNU treatment was reduced by 76, 41 and 53% in rats fed garlic, SAC and DADS, respectively, compared to controls (P<0.05). Total tumor number was reduced 81, 35 and 65% by these supplements, respectively (P<0.05). In a separate study the quantity of mammary DNA alkylation occurring 3 h after MNU treatment was reduced in rats fed garlic, SAC or DADS (P<0.05). Specifically, O(6)-methylguanine adducts were reduced by 27, 18 and 23% in rats fed supplemental garlic, SAC and DADS, respectively, compared to controls. N(7)-Methylguanine adducts decreased by 48, 22 and 21% respectively, compared to rats fed the control diet. These studies demonstrate that garlic and associated allyl sulfur components, SAC and DADS, are effective inhibitors of MNU-induced mammary carcinogenesis.
Insights
Dietary garlic powder, S-allyl cysteine (SAC), and diallyl disulfide (DADS) significantly inhibit mammary tumors and DNA alkylation induced by N-methyl-N-nitrosourea (MNU). These natural compounds offer protective effects against chemical-induced mammary carcinogenesis.
Area of Science:
- Oncology
- Nutritional Science
- Biochemistry
Background:
- Previous research indicated garlic powder inhibits N-nitrosamine-induced DNA alkylation.
- Mammary tumorigenesis is a significant health concern, often influenced by environmental and chemical carcinogens.
Purpose of the Study:
- To compare the efficacy of garlic powder, S-allyl cysteine (SAC), and diallyl disulfide (DADS) in preventing N-methyl-N-nitrosourea (MNU)-induced mammary tumors.
- To investigate the impact of these supplements on MNU-induced DNA alkylation in mammary tissue.
Main Methods:
- Female Sprague-Dawley rats were supplemented with garlic powder, SAC, or DADS for two weeks before MNU administration.
- Tumor incidence and total tumor number were assessed 23 weeks post-MNU treatment.
- Mammary DNA alkylation (O(6)-methylguanine and N(7)-methylguanine adducts) was quantified 3 hours after MNU treatment.
Main Results:
- Garlic powder, SAC, and DADS significantly delayed mammary tumor onset.
- Tumor incidence was reduced by 76% (garlic), 41% (SAC), and 53% (DADS).
- Total tumor number decreased by 81% (garlic), 35% (SAC), and 65% (DADS).
- Mammary DNA alkylation was significantly reduced by all supplements, with O(6)-methylguanine adducts decreasing by 27% (garlic), 18% (SAC), and 23% (DADS).
- N(7)-methylguanine adducts decreased by 48% (garlic), 22% (SAC), and 21% (DADS).
Conclusions:
- Garlic powder, SAC, and DADS are effective chemopreventive agents against MNU-induced mammary carcinogenesis in rats.
- These allyl sulfur compounds demonstrate significant inhibitory effects on both tumor development and DNA damage.
- The findings support the role of garlic and its constituents in mitigating chemically induced cancer risk.
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