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

Table 1 Composition of diets tested.

Component	Diet
	F0	F20	F50	O0	O20	O50
			g/kg diet
Cornstarch	449.5	442.5	431.6	449.5	442.5	431.6
Casein	200	195.4	188.6	200	195.4	188.6
Sucrose	100	100	100	100	100	100
Fresh oil	150	150	150
OFO1				150	150	150
Fiber	50	41.6	29.3	50	41.6	29.3
Minerals2	35	35	35	35	35	35
Vitamins3	10	10	10	10	10	10
L-Cysteine	3	3	3	3	3	3
Choline	2.5	2.5	2.5	2.5	2.5	2.5
Tert-butyl- hydroquinone	0.014	0.014	0.014	0.014	0.014	0.014
H. cordata powder	0	20	50	0	20	20

¹OFO: oxidized frying oil;

²AIN-93 mineral mixture;

³AIN-93 vitamin mixture.

Table 2 Body weight gain, food intake and feed efficiency of Sprague-Dawley rats fed with fresh/oxidized frying oil and 0%, 2% and 5% H. cordata thunb powder diets for 4 wk (mean±SD, n = 8).

Group	Body weight gain (g/wk)	Food intake (g/wk)	Feed efficiency (B.W gain/food intake)
F0	46.71±3.20	202.31±7.62	0.23±0.03
F20	44.85±2.82	206.22±7.82	0.22±0.04
F50	47.54±2.36	212.34±5.20	0.22±0.01
O0	35.62±2.101	198.14±5.47	0.18±0.02
O20	37.91±4.75	185.25±4.66	0.20±0.03
O50	38.54±4.55	188.72±3.44	0.20±0.02
ANOVA2
Dose	NS3	NS	NS
Oil	P<0.05	NS	NS
Dose×Oil	NS	NS	NS

¹Mean values significantly differ between the two oil groups (P<0.05).

²Analyzed by a two-way ANOVA. 3NS: No significance.

Table 3 Liver microsomal protein content (CYP450) and the activity of liver NADPH reductase in Sprague-Dawley rats fed with the fresh/oxidized frying oil and 0%, 2% and 5% H. cordata thunb powder diets for 4 wk (mean±SD, n = 8).

Group	Microsomal protein (mg/g liver)	CYP450 (nmol/mg protein)	NADPH reductase (nmol/mg protein)
F0	13.36±4.711	0.61±0.271	202.31±28.11
F20	15.66±0.961	0.73±0.101	228.42±30.41
F50	15.79±1.351	0.74±0.141	225.64±25.3
O0	23.74±2.54	1.63±0.75	256.03±31.12
O20	22.13±3.76	2.14±1.10	288.55±29.63
O50	22.25±2.96	2.08±0.15	234.15±25.42
ANOVA4
Dose	NS5	NS	NS
Oil	P<0.05	P<0.05	P<0.05
Dose×Oil	P<0.05	P<0.05	NS

¹Mean values significantly differ between the two oil groups (P<0.05). ^2,3Means not sharing common superscript letters significantly differ from one another by Duncan’s multiple range test for the same oil group (P<0.05).

⁴Analyzed by a two-way ANOVA.

⁵NS: No significance.

Table 4 Activity of aniline hydroxylase (ANH) and aminopyrine demethylase (AMD) from the liver of Sprague-Dawley rats fed with the fresh/oxidized frying oil and 0%, 2% and 5% H· cordata thunb powder diets for 4 wk (mean±SD, n = 8).

Group	ANH (mmol/min/mg protein) (×10-5)	AMD (nmol/min/mg protein)
F0	3.74±1.541	6.76±0.421
F20	3.05±1.061	5.34±1.02
F50	4.21±1.251	6.31±0.561
O0	13.46±0.613	8.91±0.233
O20	8.18±0.432	6.02±0.112
O50	11.74±0.373	9.03±0.543
ANOVA4
Dose	P<0.05	NS5
Oil	P<0.05	P<0.05
Dose×Oil	P<0.05	P<0.05

¹Mean values significantly differ between the two oil groups (P<0.05). ^2,3Means not sharing common superscript letters significantly differ from one another by Duncan’s multiple range test for the same oil group (P<0.05). ⁴Analyzed by a two-way ANOVA.

⁵NS: No significance.

Table 5 Activity of EROD and PROD from the liver of Sprague- Dawley rats fed with the fresh/oxidized frying oil and 0%, 2% and 5% H· cordata thunb powder diets for 4 wk (mean±SD, n = 8).

Group	EROD (pmol/min/mg protein)	PROD (pmol/min/mg protein)
F0	55.61±5.121	8.32±4.111
F20	52.14±3.201	6.12±1.251
F50	52.46±4.581	5.98±1.541
O0	88.62±5.263	25.39±3.59
O20	78.23±4.412	20.12±2.18
O50	75.26±5.892	21.33±2.66
ANOVA4
Dose	NS5	NS
Oil	P<0.05	P<0.05
Dose×Oil	NS	NS

¹Mean values significantly differ between the two oil groups (P<0.05). ^2,3Means not sharing common superscript letters significantly differ from one another by Duncan’s multiple range test for the same oil group (P<0.05).

⁴Analyzed by a two-way ANOVA.

⁵NS: No significance.

Table 6 The activity of quinone reductase from the liver of Sprague- Dawley rats fed with the fresh/oxidized frying oil and 0%, 2% and 5% H· cordata thunb powder diets for 4 wk (mean±SD, n = 8).

Group	Quinone reductase (nmol/min/mg protein)
	Microsomal suspension	Liver homogenate
F0	106.31±25.421	170.47±25.652
F20	136.54±31.85	226.77±30.953
F50	122.42±29.431	216.37±29.853
O0	145.17±30.62	475.92±22.10
O20	144.38±26.66	490.14±15.31
O50	149.74±24.85	484.31±15.12
ANOVA4
Dose	NS5	P<0.05
Oil	P<0.05	P<0.05
Dose×Oil	NS	P<0.05

¹Mean values significantly differ between the two oil groups (P<0.05). ^2,3Means not sharing common superscript letters significantly differ from one another by Duncan’s multiple range test for the same oil group (P<0.05).

⁴Analyzed by two-way ANOVA.

⁵NS: No significance.