HPLC-QTOF-MS-based chemical Profiling and antioxidant activity of Qatari propolis

Abstract

The chemical composition of propolis (a phytochemical-rich, health-promoting bee product) varies highly with region and season, necessitating its thorough characterization. In this study, the chemical profiling of Qatari propolis (QP) was investigated using HPLC-QTOF-MS, along with its antioxidant activity in the ABTS assay. The yield of QP hydroalcoholic extracts (70%), their total flavonoid content (TFC), and total phenolic content (TPC) were in the ranges of 7.83–33.47%, 4.2–21.6%, and 3–14%, respectively. With increasing extract yield, the amount of TFC and TPC also increased. However, the observed promising antioxidant activity of QP samples was not linked to their TPC and TFC, probably because it depends on phenolic and flavonoid composition rather than their quantities. In the QP samples, compounds from different classes, such as flavonoids, fatty acyl glycosides, peptides, monoacyl glycerols, alkaloids, amino glycosides, cinnamic acids and derivatives, coumarins, phenolic glycosides, fatty amides, fatty acids, and derivatives were identified. Among these, flavonoids was the largest class, of which more than half of the compounds were prenylated flavonoids. This highlights the presence of prenylated flavonoids as a unique characteristic of QP. Altogether, QP samples could be a unique natural ingredient for the healthcare and food sectors.