Olive oil and its phenolic compounds (hydroxytyrosol and tyrosol) ameliorated TCDD-induced heptotoxicity in rats via inhibition of oxidative stress and apoptosis

Context: Naturally occurring polyphenols including olive oil (OO) and its constituents hydroxytyrosol (HT) and tyrosol (TY), consumed in the Mediterranean diet, have shown to treat various ailments due to their remarkable antioxidant properties.Objective: The present study investigates the hepatoprotective effects of OO and its phenolic compounds HT and TY against TCDD-induced hepatotoxicity in male Wistar rats.Materials and methods: TCDD was administered at a dose of 100ng/kg p.o. for 20d. Administration of OO (10ml/kg; oral), HT (0.5mg/kg; oral), and TY (30mg/kg; i.p) was started 5d prior to TCDD administration, and continued for 25d with or without TCDD administration. At the end of the experiment (25d), blood was taken for biochemical analyses and liver for the measurement of macromolecular damages, antioxidant status, expressions of CYP1A1, and apoptotic factors.Results: TCDD administration resulted in significant (p<0.05) increase in the level of hepatic stress markers ALT (101.63.07IU/l), AST (295.0 +/- 3.0IU/l), and ALP (266.66 +/- 3.7IU/l). Also, biochemical analyses of liver reported elevation in nitrite and protein carbonyl content and depletion of NQO1 and HO. However, OO, HT, and TY restored the antioxidant status. Protein expressions by Western Blot technique showed an increase in the level of CYP1A1 and Bax and a decreased level of Bcl-2 on TCDD treatment, and vice versa on OO, HT, and TY treatment.Discussion and conclusion: Our work concludes that dietary supplementation of OO, HT, and TY could serve as a potential preventive drug for TCDD-induced hepatotoxicity.