RESUMO
This paper reports the potential antimutagenicity of some components of dairy products. For both milk and fermented milk, Bifidobacterium sp. Bio (strain Danone 173010), casein and calcium showed a dose-dependent antimutagenic activity against benzo[a]pyrene mutagenicity in the Ames test using Salmonella typhimurium TA98. Fatty compounds present in milk had no antimutagenic effect. At the level occurring in cultured or uninoculated milks, and even more, the bifidobacteria, casein and calcium showed less antimutagenic activity than fermented and uninoculated milks. So, the mix of all these components must contribute to the total protective effect of dairy products against induced mutagenicity, and this does not rule out the possibility of contribution of other unknown substances. The total antimutagenicity of uninoculated skim milk corresponds to the additional activity of casein and calcium. The observed antimutagenic activity of fermented skim milk remains lower than expected.
Assuntos
Antimutagênicos/farmacologia , Bifidobacterium/fisiologia , Fosfatos de Cálcio/farmacologia , Caseínas/farmacologia , Leite , Animais , Benzo(a)pireno/antagonistas & inibidores , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
This study reports the modulating effect of some dairy products on initiation of putative preneoplasic lesions in rat colon (aberrant crypts) by 1,2-dimethylhydrazine dihydrochloride. Uninoculated skim milk, skim milk fermented with Bifidobacterium sp Bio (Danone strain 173010), and a suspension of the same lactic acid bacteria were incorporated in the animals' diet. The tested diets significantly reduced the incidence of aberrant crypts compared with the control diet by 51%, 49%, and 61%, respectively. The effects of the diets on cecal pH, hepatic UDP-glucuronyltransferase activity, and cecal microflora enzyme beta-glucuronidase were also studied. There was no significant difference in cecal pH between rats fed experimental diets and control rat. The diet supplemented with the Bifidobacterium strain suspension significantly decreased only the cecal beta-glucuronidase activity. Both enzyme activities were reduced in rats fed fermented skim milk- or uninoculated skim milk-supplemented diets compared with control animals.
Assuntos
Neoplasias do Colo/prevenção & controle , Laticínios , Lesões Pré-Cancerosas/prevenção & controle , Animais , Bifidobacterium/fisiologia , Carcinógenos , Ceco/enzimologia , Neoplasias do Colo/induzido quimicamente , Neoplasias do Colo/patologia , Laticínios/microbiologia , Dimetilidrazinas , Glucuronidase/análise , Concentração de Íons de Hidrogênio , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/ultraestrutura , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Ratos , Ratos Sprague-DawleyRESUMO
The antimutagenic effects of uninoculated milk and milks cultured with Bifidobacterium or Lactobacillus strains towards the mutagenicity induced by two direct mutagens, 4-nitroquinoline N-oxide and 2-nitrofluorene, and three dietary indirect mutagens, aflatoxin B1, benzo(a)pyrene and quercetin, were investigated using the in vitro Salmonella typhimurium test. Each cultured milk sample and control milk had a significant antimutagenic effect, to an extent varying with the mutagen used. Uninoculated milk had a greater inhibitory effect than cultured milks towards dietary indirect mutagens.