Genotoxic and antigenotoxic properties of Baccharis trimera in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Baccharis trimera (Less.) (Asteraceae) is a native plant from Brazil. Also known as "carqueja", it is popularly used to treat liver diseases, diabetes, as well as digestive disorders, mainly by women with lower socioeconomic status. AIM OF THE STUDY: The aim of the present study was to investigate the in vivo genotoxic/antigenotoxic and mutagenic potential of this plant, using the comet and the micronucleus assays. MATERIAL AND METHODS: Female adult mice were treated with 500, 1000 or 2000 mg/kg of B. trimera aqueous extract (Bt-AE) by gavage for three consecutive days. RESULTS: Independently of the dose, no genotoxic effect was observed in blood and liver samples analyzed by the comet assay. Conversely, B. trimera showed an antigenotoxic effect in blood from treated mice, thus protecting cells against oxidative DNA damage induced by the ex vivo treatment with hydrogen peroxide. In addition, Bt-AE showed in vitro antioxidant activity, assessed by DPPH and xanthine oxidase assays, suggesting that the observed antigenotoxic effects might be related to its antioxidant properties. CONCLUSIONS: However, the extract increased the frequency of micronucleus in bone marrow of treated mice, indicating a chromosomal mutagenic activity. Thus, medicines prepared from this plant should be used with caution, although the results also suggest antigenotoxic effects for B. trimera aqueous extract.

Mutagenic and genotoxic effects of Baccharis dracunculifolia (D.C.).

Baccharis dracunculifolia (D.C.) (Asteraceae), a native plant to Brazil known as "vassourinha" or "alecrim-do-campo", is the most important botanical source of a Brazilian propolis called green propolis. The leaf extracts of this plant have been used to treat liver and digestive disorders. It has been recognized that green propolis can induce mutagenic effects at high doses, but no study reporting possible mutagenic effects by Baccharis dracunculifolia extracts in the maximum tolerated dose has been conducted. The aim of the present study was to investigate the genotoxic and mutagenic effects of this plant in vivo. Adult CF-1 mice were treated with 0.5g/kg, 1.0g/kg or 2.0g/kg of an aqueous extract of Baccharis dracunculifolia by gavage for 3 consecutive days. Blood and liver samples were collected to detect DNA damage using the comet assay, while bone marrow samples were used to assess chromosome mutations by the micronucleus test. The extract increased the DNA damage in blood and liver tissues and the frequency of micronucleus in bone marrow. These findings suggest genotoxic and mutagenic effects of Baccharis dracunculifolia comparable to green propolis in mice.