Affiliations: Vestibulocochlear Research Center and Department of
Biochemistry, School of Medicine, Wonkwang University, Chonbuk, Republic of
Korea | Phytochemistry Research Laboratory, Korea Research
Institute of Chemical Technology, Daejeon, Republic of Korea | Vestibulocochlear Research Center and Department of
Microbiology, School of Medicine, Wonkwang University, Chonbuk, Republic of
Korea | Functional Food Research Center, Korea Food Research
Institute, Gyungki-do, Republic of Korea
Note: [] Address for correspondence: Bok-Ryang Kim, Ph.D., Department of
Biochemistry, School of Medicine, Wonkwang University, Iksan, Chonbuk 570-749,
Republic of Korea. Tel.: +82 63 850 6756; Fax: +82 63 841 1616; E-mail:
bokim@wonkwang.ac.kr
Abstract: In this study, we examined the protective effects of
Caesalpinia sappan L. and its major component, brazilin, against
tert-butylhydroperoxide (t-BHP)-induced cell death in House Ear Institute-Organ
of Corti 1 (HEI-OC1) cells. We found that the extract of C. sappan L. and
brazilin induced antioxidant response element (ARE)-luciferase activity and
heme oxygenase-1 (HO-1) expression in a concentration-dependent manner. The
inductive effect of brazilin was more potent than the extract of C.
sappan L. and the expression of HO-1 reached a peak at 12 h after brazilin
treatment. The extract and brazilin protected the cells against t-BHP-induced
cell death. Their protective effects were abrogated by zinc protoporphyrin IX
(ZnPP IX), a HO inhibitor. These results demonstrate that the extract of
C. sappan L. and brazilin induce the expression of HO-1 and the enzyme
diminishes t-BHP-induced cell death in HEI-OC1 cells.
