Hj. Park et al., Apoptosis-inducing costunolide and a novel acyclic monoterpene from the stem bark of Magnolia sieboldii, ARCH PH RES, 24(4), 2001, pp. 342-348
In a course of obtaining more amount of bioactive costunolide and successiv
e phytochemical isolation from Magnolia sieboldii (Magnoliaceae), a novel a
cyclic monoterpene 1 named deoxygeraniol {2,6(E)-dimethyl-2,6-octadiene} wa
s isolated along with beta -sitosterol 3-O-linoleate (2), trilinolein (3) a
nd high amount of costunolide (4) in the pure state. The structure of compo
und 1 was determined on the basis of spectroscopic data. Costunolide was fo
und to induce apoptotic cell death in a dose-dependent manner by nucleosoma
l DNA ladder and flow cytometric analysis. Immunoblot analysis showed that
the level of the anti-apoptotic protein, Bcl-2, was decreased, whereas the
cleavage of poly-(ADP-ribose) polymerase was activated. Furthermore, the N-
acetyl-L-cysteine antioxidant effectively prevented costunolide-induced cyt
otoxicity. These results suggest that costunolide-induced cell death is med
iated by reactive oxygen species.