Genotoxic action of the sesquiterpene lactone glaucolide B on mammalian cells in vitro and in vivo

Glaucolide B is a sesquiterpene lactone isolated from Vernonia eremophila M art. (Vernonieae, Asteraceae) and has schistosomicidal, antimicrobial and a nalgesic activities. This study examined the cytotoxic and clastogenic acti vities of glaucolide B in human cultured lymphocytes and in bone marrow cel ls from BALB/c mice. The mitotic index (MI) and chromosomal aberrations wer e analyzed in both of the above systems, whereas sister chromatid exchanges (SCE) and the proliferation index (PI) were determined only in vitro. In h uman cultured lymphocytes, glaucolide B concentrations greater than 15 mu g /ml of culture medium completely inhibited cell growth. At 4 mu g/ml and 8 mu g/ml of culture medium, glaucolide B significantly increased the frequen cy of chromosomal aberrations in lymphocytes and was also cytotoxic at conc entrations greater than or equal to 8 mu g/ml; there was no increase in the frequency of SCE. Glaucolide B (160-640 mg/kg) did not significantly incre ase the frequency of chromosomal aberrations in mouse bone marrow cells nor did it affect cell division. Since glaucolide B showed no clastogenic acti on on mammalian cells in vivo but was cytotoxic and clastogenic in vitro, c aution is needed in its medicinal use.