Magnoliae flos induces apoptosis of RBL-2H3 cells via mitochondria and caspase.
BACKGROUND
Magnoliae flores (MF), the buds of Magnolia denudata Desrousseaux, have been successfully used for the management of allergic diseases in Korea. The purpose of the present study was to determine their causal role in inducing apoptosis of mast cells and to verify the underlying mechanism.


METHODS
The viability of mast cells was assessed by the trypan blue exclusion test. Induction of apoptosis was confirmed by DNA fragmentation, nuclear staining and DNA hypoploidy. Western blotting and immunofluorescent staining were performed to study the alterations in expression level and translocation of apoptosis-related proteins. Mitochondrial membrane potential (MMP) change and cytochrome C release were assayed.


RESULTS
We present several lines of evidence indicating that MF induce apoptosis. Changes in cell morphology, generation of DNA fragmentation, cell cycle arrest, activation of caspase-3, and PARP and DFF degradations were demonstrated. The reduction of MMP and the release of cytochrome C to cytosol were also shown. Either PTP blockers, bongkrekic acid and cyclosporin A, or pancaspase inhibitors, Boc.D-fmk and zVAD-fmk, did not prevent the release of cytochrome C. Bax protein content was increased, and Bax was translocated from cytosol into mitochondria at early time points after MF treatment.


CONCLUSIONS
We have demonstrated that MF induce mitochondria- and caspase-dependent mast cell apoptosis. Our observations contribute new insights to the role of MF and support the view that the clinical effect of MF may depend on their pharmacological efficacy in regulating mast cell apoptosis.
Kim
Gyoo C
GC
Department of Oral Anatomy and Cell Biology, Busan National University College of Dentistry, Busan, South Korea.
Lee
Soon G
SG
Park
Bong S
BS
Kim
Jee Y
JY
Song
Yeon S
YS
Kim
Jong M
JM
Yoo
Ki S
KS
Huh
Gi Y
GY
Jeong
Min H
MH
Lim
Young Jin
YJ
Kim
Hyung M
HM
Yoo
Young Hyun
YH
D000818:Animals; D018926:Anti-Allergic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000502:physiology; D035264:Flowers; D006801:Humans; D031566:Magnolia; D008407:Mast Cells / Q000187:drug effects* / Q000502:physiology; D008928:Mitochondria / Q000502:physiology; D010936:Plant Extracts / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
D018926:Anti-Allergic Agents; D010936:Plant Extracts; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases