The genotoxic and antigenotoxic effects of Aloe vera leaf extract in vivo and in vitro

The genotoxic and antigenotoxic effects of Aloe vera leaf extract (AV) were investigated using the chromosome aberrations (CAs) test for the bone marrow cells of rats, sister chromatid exchanges (SCEs) and micronucleus (MN) and CAs tests for human lymphocytes, and the Ames Salmonella/microsome test system. In the bone marrow cells of rats, AV extract significantly induced structural and total CAs at all concentrations and in all treatment periods. In human peripheral lymphocytes, AV did not increase the mean SCE; however, it significantly induced the MN frequency and structural CAs. In addition, AV showed a cytotoxic effect by decreasing the replication index (RI), mitotic index (MI), and nuclear division index (NDI) in human lymphocytes and by decreasing the MI in the bone marrow cells of rats. AV did not decrease the genotoxicity or cytotoxicity of urethane (ethyl carbamate, EC) in the bone marrow cells of rats or in the mitomycin-C (MMC) in human lymphocytes. AV was a weak mutagen in the TA98 strain of Salmonella typhimurium in the absence of S9mix; however, AV+NPD (4-nitro-o-phenylenediamine) and AV+SA (sodium azide) exhibited a synergism in increasing the number of revertants for the TA98 and TA100 strains in the absence of S9mix, respectively.