Genotoxic and Antigenotoxic Activity of Silymarin by an in Vivo Bone Marrow Micronucleus Assay and Comet Assay

Introduction: silymarin is obtained from silybum marianum (milk thistle), an edible plant that has long been used medicinally for the treatment of liver-related disorders. silymarin is a powerful hepatoprotective and antioxidant but the anticlastogenic activity, which is an important aspect of its cancer chemoprevention is not known; hence the present investigation was carried out to study its anticlastogenic and dna protective activity in balb/c mouse.material & methods: after silymarin injections, the mice were administered either cyclophosphamide (cp) or mitomycin c (mmc) intraperitoneally and were sacrificed at 24 hrs, 48 hrs and 72 hrs after the last dose. in vivo bone marrow micronucleus assay and comet assay in whole blood were performed.results: silymarin produced an increased number of micronucleated polychromatic erythrocytes in in vivo bone marrow micronucleus assay. similarly it showed anticlastogenic activity against mutagens cyclophosphamide (cp) and mitomycin c (mmc) and caused significant reduction in the number of micronucleated polychromatic erythrocytes. in comet assay, it produced dna damage, however silymarin showed dna protective action against mutagens cp and mmc.conclusion: silymarin has chemopreventive potentials against cp and mmc induced clastogenicity in balb/c mice. ironically, it has also been found to induce clastogenicity and dna damaging effects. hence, large-scale investigations are essential to confirm the clastogenic effect before continuing the use of silymarin for therapeutic purposes