Abstract:To understand the antioxidant active components in fruits of Amalocalyx yunnanensis, the antioxidant activity and cytotoxicity of different polar fractions of the fruit’s ethanol extract were evaluated through in vitro antioxidant experiments and the MTT colorimetric method. Meanwhile, the total acid and total phenol contents of each fraction were determined, and their correlations with antioxidant activity were analyzed. The chemical components of the fraction with the best antioxidant activity were analyzed by ultra-high performance liquid chromatography coupled with Q-Exactive Orbitrap mass spectrometry (UHPLC-QE-MS) to identify the anti- oxidant active components. The results showed that the ethanol extract of A. yunnanensis fruits and its different polar fractions all had certain antioxidant activities and were non-toxic to LO2 cells. The total acid and total phenol contents were positively correlated with antioxidant activity. Among them, the ethyl acetate fraction had the strongest antioxidant activity and the highest total acid and total phenol contents, which were 835 g/kg and 14.49%, respectively. Through UHPLC-QE-MS analysis, a total of 98 compounds were identified, among which flavonoids and phenolic acids accounted for 30.21% and 14.58%, respectively, which might be the main active components of the ethyl acetate fraction. Therefore, it could provide a basis for the development of A. yunnanensis fruits as natural and safe antioxidants.
