RESUMEN
Chresta martii (Asteraceae), found in the Xingó region, northeastern Brazil, is used in the treatment of gastrointestinal (GIT) and liver disorders and malaria. However, there are few studies regarding efficacy and safety of use for this species. Thus, the objective of this study was to determine in vivo acute toxicity and in vitro cytotoxicity of organic extracts of C. martii as well as in vivo genotoxicity of its semipurified fraction. Dried aerial parts of C. martii were extracted using three organic solvents (cyclohexane [ECCm], ethyl acetate [EACm], and ethanol [EECm]), and these extracts were examined for acute toxicity (50-2000 mg/kg ip or po) and cytotoxicity (50 µg/ml) in carcinogenic human cell lines (HL-60, NCIH-292, and MCF-7). The EACm, which showed evidence of toxicity (in vivo and in vitro), was fractionated on a silica column, yielding four fractions (F1-F4). The F1 was utilized for genotoxicity (50 mg/kg ip), by in vivo micronucleus (MN) assay. ECCm showed no indication of acute toxicity or occurrence of death, while the LD50 estimated for the extracts (EACm and EECm) was 500 mg/kg po and 200 mg/kg ip. The EACm (50 µg/ml) inhibited growth of tumor cells HL-60 (96.54%), NCIH-292 (73.43%), and MCF-7 (15%). The F1 fraction induced MN formation in polychromatic erythrocytes of Swiss Webster mice. Organic extracts from C. martii exhibited acute toxicity classified as mild to moderate, in addition to cytotoxicity (in vitro), while the F1 semipurified fraction induced genotoxicity (in vivo).