Affiliations: Department of Radiation Emergency Medicine, National
Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba, 263-8555,
Japan | Heavy-Ion Radiobiology Research Group, National
Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba, 263-8555,
Japan | Department of Material and Life Science, Graduate
School of Engineering, Osaka University, SORST, Japan Science and Technology
Agency (JST), Suita, Osaka 565-0871, Japan
Note: [] Address for correspondence: Keiko Suzuki, Ph.D., Department of
Radiation Emergency Medicine, National Institute of Radiological Sciences,
Anagawa 4-9-1, Inage-ku, Chiba, 263-8555, Japan. Tel.: +81 43 206 3127; Fax:
+81 255 6819; E-mail: [email protected]
Abstract: Among antioxidative polyphenols, caffeic acid esters such as caffeic
acid phenethyl ester (CAPE) and chlorogenic acid are contained in propolis,
vegetables and coffee. In this study, we compared the efficacy of some
polyphenols on the activation level of a cytoprotective heme oxygenase-1 (HO-1)
gene in RAW264.7 mouse macrophage cells using quantitative real-time RT-PCR.
The quantitative study revealed a variety of activation level of HO-1 gene by
the chemicals. CAPE and caffeic acid ethyl ester (CAEE) at the final
concentration of 2 μM drastically activated the HO-1 gene
to 39.2-fold and 20.1-fold, respectively. Curcumin, structurally related with
caffeic acid and an element of turmeric, induced the HO-1 gene to 5.8-fold. In
contrast, no activation was observed by other caffeic acid esters such as
chlorogenic acid and rosmarinic acid. Higher concentrations were necessary for
the activation by an antioxidant cysteamine and the electrophile diethyl
maleate. Although the inducible activities of CAPE and chlorogenic acid were
distinctly different, they showed similar reductive capacities when determined
by cyclic voltammetry. These results show that the drastic activation of HO-1
gene by CAPE and CAEE is dependent upon their chemical structures, rather than
the reductive activity of polyphenols, possibly reflecting the physiological
effects of the nutritional elements.
