AIM: To evaluate the effects of frying oil and Houttuynia cordata Thunb (H. cordata), a vegetable traditionally consumed in Taiwan, on the xenobiotic-metabolizing enzyme system of rodents. METHODS: Forty-eight Sprague...AIM: To evaluate the effects of frying oil and Houttuynia cordata Thunb (H. cordata), a vegetable traditionally consumed in Taiwan, on the xenobiotic-metabolizing enzyme system of rodents. METHODS: Forty-eight Sprague-Dawley rats were fed with a diet containing 0%, 2% or 5% H. cordata powder and 15% fresh soybean oil or 24-h oxidized frying oil (OFO) for 28 d respectively. The level of microsomal protein, total cytochrome 450 content (CYP450) and enzyme activities including NADPH reductase, ethoxyresorufin 0-deethylase (EROD), pentoxyresorufin 0-dealkylase (PROD), aniline hydroxylase (ANH), aminopyrine demethylase (AMD), and quinone reductase (QR) were determined. QR represented phase Ⅱ enzymes, the rest of the enzymes tested represented phase Ⅰ enzymes. RESULTS: The oxidized frying oil feeding produced a significant increase in phase Ⅰ and Ⅱ enzyme systems, including the content of CYP450 and microsomal protein, and the activities of NADPH reductase, EROD, PROD, ANH, AMD and QR in rats (P<0.05). In addition, the activities of EROD, ANH and AMD decreased and QR increased after feeding with H. cordata in OFO-fed group (P<0.05). The feeding with 2% H. cordata diet showed the most significant effect. CONCLUSION: The OFO diet induces phases I and II enzyme activity, and the 2% H. cordata diet resulted in a better regulation of the xenobiotic-metabolizing enzyme system.展开更多
AIM： To evaluate the effect of inflammatory cytokines on arylamine N-acetyltransferase 1 （NAT1）, which is a phase-U enzyme involved in the biotransformation of aromatic and heterocyclic amines found in food, drugs ...AIM： To evaluate the effect of inflammatory cytokines on arylamine N-acetyltransferase 1 （NAT1）, which is a phase-U enzyme involved in the biotransformation of aromatic and heterocyclic amines found in food, drugs and the environment. METHODS： Human cholangiocarcinoma KKU-100 cells were treated with a mixture of proinflammatory cytokines （interferon-7, interleukin-l and tumor necrosis factor-m） for 48 h, and the effect on NAT1 activity was assessed by high performance liquid chromatography, while NAT1 expression was determined by reverse-transcription polymerase chain reaction. The oxidative stress on the cells was examined by the formation of nitric oxide, superoxide anion and glutathione （GSH） levels. The cells were also treated with S-nitroso-glutathione （GSNO）, a nitric oxide donor, to see if the responses were similar to those obtained with the inflammatory cytokines. RESULTS： Cytokines suppressed NAT1 activity, reducing the Vmax without affecting the Am. Cytokines also had a significant impact on the induction of nitric oxide production and in reducing the redox ratios of glutathione （GSH） and GSH disulfide. Treatment with GSNO for 2-48 h reduced NAT1 activity without affecting the GSH ratio. Moreover, inflammatory cytokines and GSNO suppressed NAT1 mRNA expression. CONCLUSION： These findings indicate an association between inflammation and suppression of NAT1, which perhaps contributes to chemical-mediated toxicity and carcinogenesis,展开更多
基金Supported by Grant From the National Science Council of Taiwan, No. NSC 90-2320-13-038-038
文摘AIM: To evaluate the effects of frying oil and Houttuynia cordata Thunb (H. cordata), a vegetable traditionally consumed in Taiwan, on the xenobiotic-metabolizing enzyme system of rodents. METHODS: Forty-eight Sprague-Dawley rats were fed with a diet containing 0%, 2% or 5% H. cordata powder and 15% fresh soybean oil or 24-h oxidized frying oil (OFO) for 28 d respectively. The level of microsomal protein, total cytochrome 450 content (CYP450) and enzyme activities including NADPH reductase, ethoxyresorufin 0-deethylase (EROD), pentoxyresorufin 0-dealkylase (PROD), aniline hydroxylase (ANH), aminopyrine demethylase (AMD), and quinone reductase (QR) were determined. QR represented phase Ⅱ enzymes, the rest of the enzymes tested represented phase Ⅰ enzymes. RESULTS: The oxidized frying oil feeding produced a significant increase in phase Ⅰ and Ⅱ enzyme systems, including the content of CYP450 and microsomal protein, and the activities of NADPH reductase, EROD, PROD, ANH, AMD and QR in rats (P<0.05). In addition, the activities of EROD, ANH and AMD decreased and QR increased after feeding with H. cordata in OFO-fed group (P<0.05). The feeding with 2% H. cordata diet showed the most significant effect. CONCLUSION: The OFO diet induces phases I and II enzyme activity, and the 2% H. cordata diet resulted in a better regulation of the xenobiotic-metabolizing enzyme system.
基金Khon Kaen University Research Fund,Grant from National Science and Technology Development Agency through the Research-Yeam-Strenghtening Grant Scheme 2006
文摘AIM： To evaluate the effect of inflammatory cytokines on arylamine N-acetyltransferase 1 （NAT1）, which is a phase-U enzyme involved in the biotransformation of aromatic and heterocyclic amines found in food, drugs and the environment. METHODS： Human cholangiocarcinoma KKU-100 cells were treated with a mixture of proinflammatory cytokines （interferon-7, interleukin-l and tumor necrosis factor-m） for 48 h, and the effect on NAT1 activity was assessed by high performance liquid chromatography, while NAT1 expression was determined by reverse-transcription polymerase chain reaction. The oxidative stress on the cells was examined by the formation of nitric oxide, superoxide anion and glutathione （GSH） levels. The cells were also treated with S-nitroso-glutathione （GSNO）, a nitric oxide donor, to see if the responses were similar to those obtained with the inflammatory cytokines. RESULTS： Cytokines suppressed NAT1 activity, reducing the Vmax without affecting the Am. Cytokines also had a significant impact on the induction of nitric oxide production and in reducing the redox ratios of glutathione （GSH） and GSH disulfide. Treatment with GSNO for 2-48 h reduced NAT1 activity without affecting the GSH ratio. Moreover, inflammatory cytokines and GSNO suppressed NAT1 mRNA expression. CONCLUSION： These findings indicate an association between inflammation and suppression of NAT1, which perhaps contributes to chemical-mediated toxicity and carcinogenesis,
