Vitamin E and polyphenols could exhibit a therapeutic role in the treatment of oxidative stress-induced neurodegenerative diseases. Therefore, their ability to cross the blood-brain barrier (BBB) represents an important issue to be explored by different diet combinations. In this study, we have evaluated the ability of alpha-tocopherol to support epigallocatechin-3-gallate (EGCG), quercetin and rutin to cross the BBB, following oral administration. Eighteen rats were fed a standard diet (C), a diet supplemented with alpha-tocopherol (A), with a mixture of EGCG, quercetin and rutin (P); or with a mixture of alpha-tocopherol and the three flavonoids (AP). Flavonoids and their conjugated derivatives were assayed in brain and plasma by HPLC-MS, whereas alpha-tocopherol was detected by RP-HPLC. The oxidative damage, due to the potential pro-oxidant activity of flavonoids, was evaluated by the presence of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in hippocampal Cornus Ammonis, one of the most vulnerable sites in the brain. Our results indicate that alpha-tocopherol is able to promote quercetin transport across the BBB. The mixture of rutin and quercetin seems to favour the accumulation of quercetin and/or its conjugated derivatives in the brain. In contrast, alpha-tocopherol does not affect EGCG transport across the BBB. The densitometric analysis of 8-OHdG immunoreactivity does not reveal any difference of oxidative damage among the experimental groups. Our results suggest that alpha-tocopherol may promote quercetin transport across the BBB, leading to a significant increase of alpha-tocopherol and quercetin concentration in the brain.
Enhancement of flavonoid ability to cross the blood brain barrier of rat by co-administration with alpha-tocopherol
FERRI, PAOLA;ANGELINO, DONATO;BENEDETTI, SERENA;AMBROGINI, PATRIZIA;NINFALI, PAOLINO
2015
Abstract
Vitamin E and polyphenols could exhibit a therapeutic role in the treatment of oxidative stress-induced neurodegenerative diseases. Therefore, their ability to cross the blood-brain barrier (BBB) represents an important issue to be explored by different diet combinations. In this study, we have evaluated the ability of alpha-tocopherol to support epigallocatechin-3-gallate (EGCG), quercetin and rutin to cross the BBB, following oral administration. Eighteen rats were fed a standard diet (C), a diet supplemented with alpha-tocopherol (A), with a mixture of EGCG, quercetin and rutin (P); or with a mixture of alpha-tocopherol and the three flavonoids (AP). Flavonoids and their conjugated derivatives were assayed in brain and plasma by HPLC-MS, whereas alpha-tocopherol was detected by RP-HPLC. The oxidative damage, due to the potential pro-oxidant activity of flavonoids, was evaluated by the presence of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in hippocampal Cornus Ammonis, one of the most vulnerable sites in the brain. Our results indicate that alpha-tocopherol is able to promote quercetin transport across the BBB. The mixture of rutin and quercetin seems to favour the accumulation of quercetin and/or its conjugated derivatives in the brain. In contrast, alpha-tocopherol does not affect EGCG transport across the BBB. The densitometric analysis of 8-OHdG immunoreactivity does not reveal any difference of oxidative damage among the experimental groups. Our results suggest that alpha-tocopherol may promote quercetin transport across the BBB, leading to a significant increase of alpha-tocopherol and quercetin concentration in the brain.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.