COOPERATION OF QUERCETIN WITH ASCORBATE IN THE PROTECTION OF PHOTOSENSITIZED LYSIS OF HUMAN ERYTHROCYTES IN THE PRESENCE OF HEMATOPORPHYRIN |
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Authors: | Yasuhiro Sorata Umeo Takahama Mitsutaka Kimura |
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Institution: | Department of Pedodontics Kyushu Dental College, Kitakyushu 803, Japan;Department of Biology, Kyushu Dental College, Kitakyushu 803, Japan |
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Abstract: | Abstract— Quercetin(20–100 μ M ) suppressed photohemolysis sensitized by hematoporphyrin, while ascorbate(10–100 μ M ) stimulated it. However, in the presence of 40 μ M quercetin, ascorbate promoted the suppression. The suppression by quercetin was due to scavenging of both singlet oxygen generated by a photosensitized reaction and radicals generated by decomposition of lipid peroxides formed by a singlet oxygen-dependent reaction. In scavenging, quercetin was oxidized and the oxidation was suppressed by ascorbate. Ascorbate was oxidized by illumination in the presence of quercetin. It is suggested that the cooperation of quercetin with ascorbate in photohemolysis is due to reduction of oxidized quercetin by ascorbate regenerating the flavonol. |
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