Integrated UPLC-HRMS based metabolomics investigating hydroxytyrosol effect in human obesity

Based on World Health Organization recent data, obesity is regarded as a major public health problem [1]. So far, several in vivo studies and experimental models investigate the effect of olive oil (OO) biophenols and particular hydroxytyrosol (HT), a strong antioxidant entity of OO, in these metabolic diseases [2]. Promising results have been uncovered and nowadays research focuses on the exploration of HT effects on human metabolome.

In this study two different UPLC-HRMS platforms were incorporated for the quantification of HT in human biological fluids and the identification of metabolites-biomarkers thereof, after the administration of an encapsulated biophenols extract enriched in HT. In particular, urine and blood samples were collected in three time points from 30 overweight/obese women, randomized in three groups according to HT intake (A–15mg HT/day, B-5mg HT/day, C-placebo). After investigation and application of the appropriate extraction protocols, a UPLC-triple-quadrupole method was developed for HT detection and quantification, using multiple reaction monitoring mode and suitable collision energies. Successively, extracts were subjected to untargeted metabolomics via UPLC-Orbitrap-MS in negative and positive ionization mode using full scan and data-depending methods. After pre-treatment, data were subjected to multivariate statistical analysis assisted by chemometric tools. Well-defined groups were revealed and statistical significant metabolites-biomarkers were identified among groups. The detected HT concentration were correlated with the identified biomarkers and the corresponding weight loss of each group. Significant interrelations were observed associating HT administration with certain trends and metabolic markers.

Acknowledgements Author would like to thank IKY financial support.

• References

• 1 Obesity and Overweigt. Available at: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
• 2 Lemonakis N, Poudyal H, Halabalaki M, Brown L, Tsarbopoulos A, Skaltsounis LA, Gikas E. The LC-MS-based metabolomics of hydroxytyrosol administration in rats reveals ameliotation of the metabolic syndrome. J. Chromarog. B 2017; 1041-1042: 45-59.