We investigated the inhibitory effects of fluvastain (FV) and its metabolites (M-2, M-3, M-4, M-5, and M-7) on the formation of several reactive oxygen species (ROS), such as singlet oxygen (O-1(2)), superoxide anion (O-2(-)), hydroxy radical ((OH)-O-.), hypochlorite ion (OCL-, and linoleic acid peroxide (LOO.). Inhibitory effects of pravastatin (PV), simvastatin (SV), probucol (PR) and alpha -tocopherol (TOC) were also tested. The inhibitory effects of 5-hydroxy FV (M-2) and 6-hydroxy FV (M-3) on the formation of O-1(2), O-2(-), (OH)-O-., and OCL- were strongest. Scavenging of O-1(2) by M-4, M-5, (+)-FV, and (-)-FV was also noted. The inhibitory effects of (+)-FV on the formation Of O-1(2) were comparable to those of (-)-FV. PV, SV, PR and M-7 had little or no inhibitory effect on the formation of several ROS. In conclusion, FV and its metabolites, particulary M-2 and M-3, have the potential to protect against oxidative stress mediated by several ROS. (C) 2001 Elsevier Science Inc. All rights reserved.