US EPA

2196225 

Journal Article 

Abstract 

Effects of selected dietary antioxidant phytochemicals on the hepatic tumor promoting activity of PCB-77 

Tharappel, JC; Stemm, DN; Bunaciu, RP; Robertson, LW; Lehmler, HJ; Spear, BT; Glauert, HP 

2005 

1 

Toxicological Sciences
ISSN: 1096-6080
EISSN: 1096-0929 

84 

1-S 

303-304 

English 

Polychlorinated biphenyls (PCBs) have complete carcinogenic and promoting activities in the liver, which may be brought about in part by the induction of oxidative stress. We examined the effects of several antioxidant phytochemicals on the tumor promoting activity of 3, 3?, 4?4-tetrachlorobiphenyl (PCB-77). Female rats were first injected i.p. with DEN (150 mg/kg) and one week later the rats were fed an AIN-93 based purified diet or the same diet containing ellagic acid (0.4%), betacarotene (0.5%), curcumin (0.5%), N-acetyl cysteine (NAC) (1.0%), CoQ10 (2.0%), resveratrol (0.005%), lycopene (10% as LycoVit [BASF], which contains 10% lycopene), or epigallocatechin-3-gallate (EGCG; a 1% green tea extract containing 16.5% EGCG and 33.4% total catechins). Rats were fed the diets for the remainder of the study. After 3 weeks, 2/3 of the control and all of the antioxidant diet-fed rats were injected i.p. with PCB-77 (300 ?mol/kg) every other week for four injections. All rats were euthanized 10 days after the last PCB injection. The rats that received PCB-77 alone showed a large increase in placental glutathione Stransferase (PGST)-positive foci in the liver. Lycopene decreased the number of foci, while curcumin decreased the size of the foci. Beta-carotene decreased both the number and size of the foci. In contrast Ellagic acid increased both the number and size of the foci. All the other phytochemicals showed only minor effects. Compared with the PCB-77 group, CoQ10 increased cell proliferation in PGST-negative hepatocytes, whereas the other antioxidants had no effect. These findings show that some antioxidant phytochemicals can influence the promoting activity of PCB-77.