RESUMO
Zeocin is a member of bleomycin/phleomycin family of antibiotics isolated from Streptomyces verticullus. This unique radiomimetic antibiotic is known to bind to DNA and induce oxidative stress in different organisms producing predominantly single- and double- strand breaks, as well as a DNA base loss resulting in apurinic/apyrimidinic (AP) sites. The aim of this study was to induce an adaptive response (AR) by zeocin in freshly isolated human lymphocytes from blood and to observe whether plant extracts could modulate this response. The AR was evaluated by the comet assay. The optimal conditions for the AR induction and modulation were determined as: 2 h-intertreatment time (in PBS, at 4°C) given after a priming dose (50 µg/ml) of zeocin treatment. Genotoxic impact of zeocin to lymphocytes was modulated by plant extracts isolated from Gentiana asclepiadea (methanolic and aqueous haulm extracts, 0.25 mg/ml) and Armoracia rusticana (methanolic root extract, 0.025 mg/ml). These extracts enhanced the AR and also decreased DNA damage caused by zeocin (after 0, 1 and 4 h-recovery time after the test dose of zeocin application) to more than 50%. These results support important position of plants containing many biologically active compounds in the field of pharmacology and medicine.
