The colon epithelium as a target for the intracellular antioxidant activity of hydroxytyrosol: A study on rat colon explants

The study aimed at investigating the intracellular antioxidant activity of hydroxytyrosol (HT), one of the most potent natural antioxidant phenolic compounds, directly on the colon epithelium, under basal physiological and pro-oxidant conditions. In situ confocal microscopy on rat colon explants loaded with the ROS sensitive fluorescent probe CM-H 2 DCFDA was applied. HT exerted a dose-dependent decrease of the basal ROS production of superficial colonocytes. Also, it induced a dose-dependent antioxidant action on the colon mucosa exposed to an H 2 O 2 challenge. The effect of 100 M HT was comparable to that of 10 M Trolox. The HT effect was also tested against tert-butyl peroxide, another pro-oxidant. The results showed that HT can directly contribute to the redox balance of colonic epithelium by reducing ROS in both basal and pro-oxidant conditions, and support the potential of HT as a functional food ingredient with applications in protecting the intestinal mucosa against oxidative stress.