Safrole-2 ',3 '-oxide induces cytotoxic and genotoxic effects in HepG2 cells and in mice

Abstract

Safrole-2',3'-oxide (SAFO) is a reactive electrophilic metabolite of the hepatocarcinogen safrole, the main component of sassafras oil. Safrole occurs naturally in a variety of spices and herbs, including the commonly used Chinese medicine Xi xin (Asari Radix et Rhizoma) and Dong quai (Angelica sinensis). SAFO is the most mutagenic metabolite of safrole tested in the Ames test. However, little or no data are available on the genotoxicity of SAFO in mammalian systems. In this study, we investigated the cytotoxicity and genotoxicity of SAFO in human HepG2 cells and male FVB mice. Using MTT assay. SAFO exhibited a dose-and time-dependent cytotoxic effect in HepG2 cells with TC(50) values of 361.9 mu M and 193.2 mu M after 24 and 48 h exposure. respectively. In addition, treatment with SAFO at doses of 125 mu M and higher for 24 h in HepG2 cells resulted in a 5.1-79.6-fold increase in mean Comet tail moment by the alkaline Comet assay and a 2.6-7.8-fold increase in the frequency of micronucleated binucleated cells by the cytokinesis-block micronucleus assay. Furthermore, repeated intraperitoneal administration of SAFO (15, 30, 45, and 60 mg/kg) to mice every other day for a total of twelve doses caused a significant dose-dependent increase in mean Comet tail moment in peripheral blood leukocytes (13.3-43.4-fold) and in the frequency of micronucleated reticulocytes (1.5-5.8-fold). Repeated administration of SAFO (60 mg/kg) to mice caused liver lesions manifested as a rim of ballooning degeneration of hepatocytes immediately surrounding the central vein. Our data clearly demonstrate that SAFO significantly induced cytotoxicity. DNA strand breaks. micronuclei formation both in human cells in vitro and in mice. More studies are needed to explore the role SAFO plays in safrole-induced genotoxicity. (C) 2011 Elsevier B.V. All rights reserved.