Distribution of olive oil phenolic compounds in rat tissues after administration of a phenolic extract from olive cake

Scope The distribution and accumulation of olive oil phenolic compounds in the body are topics lacked of information. The aim of this study was to evaluate the bioavailability, metabolism and distribution of phenolic compounds from olive cake. Methods and results: The metabolism and distribution of phenolic compounds were examined by UPLC-MS/MS after an acute intake of a phenolic extract from olive cake, analyzing plasma and tissues (heart, brain, liver, kidney, spleen, testicle and thymus) 1, 2 and 4 h after ingestion using Wistar rats as the in vivo model. The results showed a wide distribution of phenolic compounds and their metabolites in the tissues, with a main detoxification route through the kidneys. Highlighting the quantification of the free forms of some phenolic compounds, such as oleuropein derivative in plasma (Cmax 4 h: 24 nmol/L) and brain (Cmax 2 h: 2.8 nmol/g), luteolin in kidney (Cmax 1 h: 0.04 nmol/g), testicle (Cmax 2 h: 0.07 nmol/g) and heart (Cmax 1 h: 0.47 nmol/g); and hydroxytyrosol in plasma (Cmax 2 h: 5.2 nmol/L), kidney (Cmax 4 h: 3.8 nmol/g) and testicle (Cmax 2 h: 2.7 nmol/g). Conclusion: After a single ingestion of olive oil phenolic compounds, these were absorbed, metabolized and distributed through the blood stream to practically all parts of the body, even across the blood-brain barrier.