ABSTRACT
This work aimed to propose two analytical methods for the quantitative and qualitative analysis of major anthocyanins and non-anthocyanin phenolic compounds in jussara (Euterpe edulis) extracts, using ultra performance liquid chromatography-mass spectrometry. These methods were evaluated for selectivity, precision, linearity, detection and quantification limits. The complete separation of 5 anthocyanins and 22 non-anthocyanins polyphenols was achieved in 4.5 and 7 min, respectively. Limits of detection ranged from 0.55 to 9.24 µg/L, with relative standard deviation for concentration up to 7.0%. In jussara extract, 13 of the 27 analytes were characterized. The dominant compound was cyanidin-3-O-rutinoside, representing about 73% of the total phenolic compounds content (approximately 23 mg/g of extract in dry weight). Other phenolic compounds found in the extract were: cyanidin-3-O-glucoside, pelargonidin-3-O-glucoside, quercetin, rutin, myricetin, kaempferol, kaempferol-3-O-rutinoside, luteolin, apigenin, catechin, ellagic acid and 4,5-dicaffeoylquinic acid.
ABSTRACT
Docosahexaenoic acid (DHA) is an n-3 polyunsaturated fatty acid that is highly enriched in the brain, and the oxidation products of DHA are present or increased during neurodegenerative disease progression. The characterization of the oxidation products of DHA is critical to understanding the roles that these products play in the development of such diseases. In this study, we developed a sensitive and specific analytical tool for the detection and quantification of twelve major DHA hydroperoxide (HpDoHE) and hydroxide (HDoHE) isomers (isomers at positions 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19 and 20) in biological systems. In this study, HpDoHE were synthesized by photooxidation, and the corresponding hydroxides were obtained by reduction with NaBH4. The isolated isomers were characterized by LC-MS/MS, and unique and specific fragment ions were chosen to construct a selected reaction monitoring (SRM) method for the targeted quantitative analysis of each HpDoHE and HDoHE isomer. The detection limits for the LC-MS/MS-SRM assay were 1-670 pg for HpDoHE and 0.5-8.5 pg for HDoHE injected onto a column. Using this method, it was possible to detect the basal levels of HDoHE isomers in both rat plasma and brain samples. Therefore, the developed LC-MS/MS-SRM can be used as an important tool to identify and quantify the hydro(pero)xy derivatives of DHA in biological system and may be helpful for the oxidative lipidomic studies.
