Giovanna Aquinoa,b, Eduardo Maria Sommellaa, Pietro Campigliaa, Giacomo Pepea

aDepartment of Pharmacy, University of Salerno, Via Giovanni Paolo II, Fisciano, 84084 Salerno, Italy.
bPhD Program in Drug Discovery and Development, University of Salerno, Fisciano, 84084 Salerno, Italy.

This project aimed to valorize agricultural by-products by investigating Allium cepa leaves, with the goal of utilizing these valuable by-products and giving them “a second life” through the production of high-value added extracts suitable for applications in the food and pharmaceutical industries. Allium cepa PDO (Protected Designation of Origin) leaves hydroalcoholic extract was obtained using a previously optimized Box Behnken Design – Microwave Assisted Extraction model [1]. The extreme chemical complexity requires enhanced separation to fully resolve the profile of the extract. In this context, we developed and optimized an online comprehensive two-dimensional (2D) liquid chromatography (LC × LC) strategy. Key parameters, in both dimensions, such as flow rates, stationary phases chemistry, and mobile phases composition, were investigated to boost peak capacity and orthogonality. The optimized method relies on a RP-LC × RP-LC combination, further hyphenated to high-resolution mass spectrometry to provide a detailed characterization of the multiple compound classes present in the Allium cepa extract. The online RP-LC × RP-LC-HRMS approach provided a good separation of secondary metabolites, yielding high resolution and peak capacity, together with a good employment of the 2D separation space. This significantly improved compound identification compared to conventional mono-dimensional (1D) analytical methods. The developed technique holds potential to standardize and define biomarkers with antioxidant properties, as reported in previous studies [1].

Acknowledgements: This study was carried out within the Agritech National Research Center and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.

Keywords: agri-food waste, green extraction, two-dimensional liquid chromatography, mass spectrometry References

References

1. Aquino G., Basilicata M.G.,  et al. Scientific Report 13, (2023) pag. 14923. DOI: 10.1038/s41598-023-42303-x