Polar phenol detection in rat brain: Development and validation of a versatile UHPLC-MS method and application on the brain tissues of Corinthian currant (Vitis vinifera L.,var. Apyrena) fed rats

Abstract

This study aimed to validate a rapid and selective bioanalytical method, using UHPLC-Orbitrap MS, for the determination of brain polar phenolics and to apply it in rats that orally consumed Corinthian currant for 38 days. Corinthian currant, is a dried vine fruit rich in polar phenolics that potentially penetrate the brain. During method optimization fresh and lyophilized tissues were comparatively studied along with different solid-phase extraction cartridges; satisfactory recoveries (>80%) for almost all analytes were attained using fresh tissues and Oasis® HLB cartridges. Brain regional levels in phenol concentrations were then determined; isoquercetin showed higher concentrations in frontal cortex, hippocampus and cerebellum (14.0 ± 5.5, 6.6 ± 2.0, and 2.9 ± 1.3 ng/g tissue, respectively); rutin and gallic acid in cerebellum and isorhamnetin, quercetin and rutin in hippocampus of the Corinthian currant supplemented rat group compared to the control. This is the first study investigating polar phenolics' accumulation in rat brain after Corinthian currant supplementation.

Keywords: Brain; Corinthian raisin; Flavonoids; LC-Orbitrap MS; Rats; Vitis vinifera L.