RESUMO
Antimutagenic activity of green tea (Camellia sinensis) was studied using Salmonella typhimurium strains (TA 102) (Ames test). Aqueous tobacco extract was found to be mutagenic to S. typhimurium TA 102 at concentration of 50 mg/plate. Green tea polyphenols was found to inhibit the mutagenicity of tobacco in a concentration-dependent manner. Concentrations needed for 50% inhibition of mutagen-induced revertant formation was found to be 5 mg/plate. Green tea polyphenols was also found to inhibit the urinary mutagenicity in rats induced by tobacco extract. Moreover green tea polyphenols were found to inhibit in vitro nitrosation reaction produced by reaction sodium nitrite and methyl urea and further inhibition of mutagenicity indicating that green tea has dual action to bring out a reduction in the mutagenic and carcinogenic potential of tobacco.
Assuntos
Antimutagênicos/farmacologia , Fitoterapia , Chá , Animais , Antimutagênicos/administração & dosagem , Antimutagênicos/uso terapêutico , Carcinógenos/toxicidade , Relação Dose-Resposta a Droga , Flavonoides/administração & dosagem , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Masculino , Testes de Mutagenicidade , Fenóis/administração & dosagem , Fenóis/farmacologia , Fenóis/uso terapêutico , Polifenóis , Ratos , Ratos Wistar , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Nicotiana/toxicidadeRESUMO
Extracts from plants of Loranthaceae family collected from 15 host trees were screened for their cytocidal activity to tumour cells. Biologically active extracts prepared from Helicanthis elasticus grown on Mangifera indica and Citrus maxima (host trees) were partially purified by the gel filtration method. The purified material was found to be cytotoxic in vitro and reduced solid and ascites tumours in mice when given either simultaneously or prophylactically. The partially purified material was found to be a protein with a molecular weight of approximately 80,000 Da.
