Brief Reports
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World J Gastroenterol. Jan 21, 2005; 11(3): 389-392
Published online Jan 21, 2005. doi: 10.3748/wjg.v11.i3.389
Effects of frying oil and Houttuynia cordata thunb on xenobiotic-metabolizing enzyme system of rodents
Ya-Yen Chen, Chiao-Ming Chen, Pi-Yu Chao, Tsan-Ju Chang, Jen-Fang Liu
Ya-Yen Chen, Jen-Fang Liu, Graduate Institute of Nutrition & Health Sciences, Taipei Medical University, Taipei, Taiwan
Chiao-Ming Chen, Graduate Institute of Pharmacy, Taipei Medical University, Taipei, Taiwan
Pi-Yu Chao, Department of Food and Nutrition, Chinese Culture University, Taipei, Taiwan
Tsan-Ju Chang, Taoyuan District, Agriculture Improvement Station, Taipei Branch, Taiwan
Author contributions: All authors contributed equally to the work.
Supported by Grant From the National Science Council of Taiwan, No. NSC 90-2320-13-038-038
Correspondence to: Dr. Jen-Fang Liu, Graduate Institute of Nutrition and Health Sciences, Taipei Medical University, 250 Wu-Shing Street, Taipei 110, Taiwan. liujenfa@tmu.edu.tw
Telephone: +886-2-27361661-6551 Fax: +886-2-27373112
Received: March 3, 2004
Revised: March 5, 2004
Accepted: March 9, 2004
Published online: January 21, 2005
Abstract

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 O-deethylase (EROD), pentoxyresorufin O-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.

Keywords: Frying oil, Houttuynia cordata thunb, Xenobiotic-metabolizing enzyme system