• Journal of Photoscience
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• v.9 no.3
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• pp.49-50
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• 2002

N-Nitrosoproline(NPRO) is endogenously formed from proline and nitrite. NPRO has been reported to be nonmutagenic and noncarcinogenic. In this study, we have detected the direct mutagenicity of NPRO with UVA and UVB towards S. typhimurium. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a mutagenic lesion, was observed in calf thymus DNA treated with NPRO plus simulated sunlight. Furthermore, the treatment with NPRO and sunlight induced single strand breaks in the superhelical replicative form of phage M13mp2 DNA. An analysis using scavengers suggested that both reactive oxygen species and NO radical mediate the strand breaks. The formation of nitric oxide was observed in NPRO solution irradiated with UVA. The co-mutagenic and co-toxic actions of NPRO and sunlight merit attention as possible mechanisms increasing the carcinogenic risk from UVA irradiation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.266-272
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• 1993

Some compounds including flavonoids were tested as scavenger of nitrite which is believed to participate in the formation of N-nitroso compound. Many were found to be potent scavengers and the most potent ones were ascorbic arid, potassium thiocyanate, chlorogenic acid, catechin, morin, luteolin, luteolin-7-glucoside, and naringenin. To evaluate the influence of the above compounds on the endogenous formation of N-nitroso compound, the amount of nitrosoproline (NPRO) was examined by co-incubation of nitrite, proline, and test compounds at various concentrations. The analysis of NPRO by High Performance Liquid Chromatography (HPLC) was newly developed. Most compounds except ascorbic acid and chlorogenic acid were found to be no effects or activatory effects on NPRO formation. From the results obtained, it was suggested that most flavonoids which are contained in our customary diets were not associated with the inhibition of NPRO formation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.1015-1018
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• 1998

Capsaicin(8-methyl-N-vanillyl-6-nonenamide: CAP) known well as a major compound of not taste in hot pepper, was investigated for the inhibition effect on in vitro nitrosation. CAP(100$\mu$mol) inhibited the formation of N-nitrosoproline(NPRO) and N-nitrosothioproline(NTPRO) by 56% and 26%, respectively. Vanillyl alcohol inhibited the nitrosation of proline by a concentration-dependent manner, and vanillic acid and vanillin were less effective in blocking the nitrosation of proline compared to CAP and anillyl alcohol. The inhibitory effect of NPRO formation by CAP was evaluated to similar with alpha-tocopherol, and vanillyl alcohol was more effective than alpha-tocopherol in blocking the nitrosation of proline. Our results suggested that CAP and its metabolites such as vanillyl alcohol could inhibit endogenous nitrosation in hydrophobic biological environment.

• Proceedings of KHEA Conference
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• 1997.07a
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• pp.253-253
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• 1997