Alpha-Bisabolol, a non toxic natural compound, strongly induces apoptosis in glioma cells

In this study, a-bisabolol, a sesquiterpene alcohol present in natural essential oil, was found to have a strong time- and dosedependent cytotoxic effect on human and rat glioma cells. After 24 h of treatment with 2.5–3.5 lM a-bisabolol, the viability of these cells was reduced by 50% with respect to untreated cells. Furthermore, the viability of normal rat glial cells was not affected by treatment with a-bisabolol at the same concentrations as above. Glioma cells treated with high concentration of a-bisabolol (10 lM) resulted in a 100% cell death. Judging from hypo-G1 accumulation, poly(ADP-ribose) polymerase cleavage, and DNA ladder formation, the cytotoxicity triggered by a-bisabolol resulted from apoptosis induction. Moreover, the dissipation of mitochondrialinner transmembrane potential and the release of cytochrome c from mitochondria indicated that, in these glioma cells, apoptosis occurred through an intrinsic pathway. As pointed out by the experimental results, a-bisabolol may be considered a novel compound able to inhibit glioma cell growth and survival