Dietary supplementation of thyme (Thymus vulgaris L.) essential oil duringthe lifetime of the rat: its effects on the antioxidant status in liver, kidney and heart tissues

This study aimed not only to identify age-related changes in certain antiox idant systems, but to assess whether dietary supplementation of thyme oil c ould address the unfavourable antioxidant-pro-oxidant balance that occurs w ith age. The present study has shown that there were significant declines i n the superoxide dismutase activities in the liver and heart of old rats, a lthough kidney showed no decline. Liver glutathione peroxidase (GSHPx) acti vity was found to have increased significantly in old rats, while a signifi cant decrease was observed in kidney. Heart GSHPX activity was not found to differ significantly between young and old rats. There were also significa nt declines in the total antioxidant status in each tissue examined. A gene ral feature of these various antioxidant parameters measured was that their activities remained higher in rats whose diets were supplemented with thym e oil, suggesting that they retained a more favourable antioxidant capacity during their life span. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.