Effect of thyme oil and thymol dietary supplementation on the antioxidant status and fatty acid composition of the ageing rat brain

The present study measured changes in antioxidant enzyme activity in, and t he phospholipid fatty acid composition of the ageing rat brain and tested w hether dietary supplementation with thyme oil or thymol could provide benef icial effects. There were significant declines in superoxide dismutase (EC 1.15.1.1) and glutathione peroxidase (EC 1.11.1.9) activities and the total antioxidant status in the untreated rats with age, while thyme-oil- and th ymol-fed rats maintained significantly higher antioxidant enzyme activities and total antioxidant status. The proportions of 18:2n-6, 20:1n-9, 22:4n-6 and 22:5n-3 in the brain phospholipids resulting from all three dietary tr eatments were significantly higher in 28-month-old rats than in 7-month-old rats. Only 20 : 1n-9 levels in 28-month-old thyme-oil- and thymol-treated rats were significantly higher than in the age-matched control. The proport ion of 22:6n-3 in brain phospholipids, which declined with age in control r ats, was also significantly higher in rats given either supplement. This la tter finding is particularly important as optimum levels of 22:6n-3 are req uired for normal brain function. These results highlight the potential bene fit of thyme oil as a dietary antioxidant.