Effects of frying oil and Houttuynia cordata thunb on xenobiotic-metabolizing enzyme system of rodents.
OBJECTIVE
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.


CONCLUSIONS
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.
Chen
Ya-Yen
YY
Graduate Institute of Nutrition and Health Sciences, Taipei Medical University, Taipei, Taiwan, China.
Chen
Chiao-Ming
CM
Chao
Pi-Yu
PY
Chang
Tsan-Ju
TJ
Liu
Jen-Fang
JF
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet; D004365:Drugs, Chinese Herbal; D004798:Enzymes / Q000378:metabolism*; D006128:Growth; D052859:Houttuynia; D051381:Rats; D017207:Rats, Sprague-Dawley; D013024:Soybean Oil / Q000494:pharmacology*; D013624:Taiwan; D014675:Vegetables; D015262:Xenobiotics / Q000378:metabolism*
D004365:Drugs, Chinese Herbal; D004798:Enzymes; C442781:Houttuynia cordata extract; D015262:Xenobiotics; D013024:Soybean Oil