Nontoxic, mutagenic, and clastogenic activities of Mate-Chimarrão (Ilex paraguariensis).

Aqueous extracts of Ilex paraguarariensis (mate-chimarrão), a species that belongs to the Aquifoliaceae family, were analyzed for the presence of genotoxic, mutagenic, and clastogenic activities through bacterial trials based on the induction of the SOS functions, as well as in human lymphocytes in vitro and in mammalian cells in vivo. The extracts of mate-chimarrão were genotoxic, as assessed by lysogenic induction in Escherichia coli, and they also induced mutagenesis in Salmonella typhimurium. They addition of S9 microsomal fraction, catalase, thiourea, or dipyridyl counteracted the genotoxic activity of mate-chimarrão, suggesting that oxygen reactive species play an essential role in the genotoxicity of mate-chimarrão extracts. The extracts were not clastogenic in vivo (bone marrow cells of rats) in our experimental conditions, but we have observed an increased frequency of chromosomal aberrations in mate-chimarrão-treated human peripheral lymphocytes. Our results suggest that a high consumption of mate-chimarrão can potentiate carcinogenesis in the human oropharynx and esophagus.

Induction of liver monooxygenases by beta-myrcene.

Beta-Myrcene (MYR) is an acyclic monoterpene found in the essential oils of a variety of useful plants such as lemongrass (Cymbopogon citratus), hop, verbena, bay and others. MYR and essential oils containing this olefinic monoterpene are widely used as flavoring food additives, as fragrances in cosmetics and as scents in household products. The present study was undertaken to investigate the induction of liver monooxygenases by MYR. Female Wistar rats were treated by gavage with MYR (1000 mg/kg body weight) or corn oil (vehicle) for 1 or 3 consecutive days. Activities of ethoxycoumarin-O-deethylase (ECOD) and alkoxy-resorufin O-dealkylases (methoxy- (MROD), ethoxy- (EROD), pentoxy- (PROD) and benzyloxy-resorufin-O-dealkylation (BROD)) were determined fluorimetrically in the hepatic microsomal fraction. Exposure to MYR, either for 1 or 3 days, produced marked (13-34-fold) increases in the activities of PROD and BROD and only minor changes in ECOD, EROD and MROD. Since PROD and BROD are metabolized mainly by CYP2B isoenzymes, these results suggest that MYR induces this phenobarbital-inducible P450 subfamily. The induction of CYP2B isoenzymes was confirmed by SDS-PAGE and immunoblotting. Levels of apoproteins CYP2B1/2B2 were increased 8.2-fold after treatment with MYR (1000 mg/kg body wt, 3 days). Results from this study therefore indicate that MYR is an inducer of isoenzymes belonging to CYP2B subfamily.

Thermophilic Campylobacter-associated diarrhoea in Rio de Janeiro.

Thermophilic Campylobacter is reported as the agent associated with chronic and acute diarrhoea in Rio de Janeiro. Nine strains were isolated from 186 children with gastroenteritis. To our knowledge this is the first report of human Campylobacteriosis in Latin-America.