Protective effects of guarana (Paullinia cupana Mart. var. Sorbilis) against DEN-induced DNA damage on mouse liver

Guarana (Paullinia cupana Mart. var. Sorbilis) is a plant originally from Brazil, which is rich in tannins. Some tannins are known to present protective effects against DNA damage. This study was performed to investigate the anti-genotoxic/cytotoxic properties of guarana in hepatocytes of mice injected with N-nitrosodiethylamine (DEN). The protective effect of guarana was evaluated both by comet assay and DNA smear fragmentation technique in two month-old female BALB/c mice. These were treated previously with 2.0 mg/g bw of guarana for 16 days and then injected with DEN (160 μg/g body weight) to induce DNA damage. The DEN-only treated group presented higher comet image length than the guarana plus DEN and untreated groups (116.06 ± 5.0 μm, 104.09 ± 3.3 μm and 93.28 ± 14.4 μm, respectively; p < 0.01). Guarana treatment presented a 52.54% reduction in comet image length when animals were exposed to DEN (p < 0.05). DNA samples from the guarana plus DEN group clearly showed less EtBr fluorescence intensity when compared to the DEN-only group, reinforcing the comet assay data. These results show, for the first time, that guarana has a protective effect against DEN-induced DNA damage in mouse liver.