The chemical profiling and identification of Abelia macrotera (Graebn. et Buchw.) Rehd. based on UHPLC-Q-Exactive Orbitrap MS and study their antioxidant, anti-tyrosinase and anti-inflammatory activities

Although Abelia macrotera has long been used as the raw material for the special snack "immortal tofu" Chinese population, the composition and activity of its leaf and stem are rarely studied. Ultrahigh-performance liquid chromatography-quadrupole (UHPLC-Q)-Exactive Orbitrap mass spectrometry and various experiments were used for in vitro study of its chemical composition and antioxidant, antityrosinase, and anti-inflammatory activities. A fast, accurate, and sensitive UHPLC-Q-Exactive Orbitrap mass spectrometry method has been established and effectively used for the determination of the chemical composition of the leaf and stem A. macrotera. The biological activities of the leaf and stem extracts of the A. macrotera were determined in vitro antioxidant and anti-inflammatory methods. A total of 142 chemical constituents including 48 flavonoids, organic acids, 12 phenylpropanoids, and 19 others were identified by UHPLC-Q-Exactive Orbitrap mass spec-trometry. The results show that the leaf and stem extracts have wide and significant antioxidant capacities, including scavenging effects of DPPH, ABTS and hydroxyl radicals, and the ability to reduce both iron and copper metal ions. Additionally, they showed a strong inhibition of NO production, with a dose-dependent inhibition. the best of our knowledge, this is the first study to report the identification and content determination of chemical components of the A. macrotera leaf and stem. These results will be beneficial to further understand medicinal value.