Antioxidant Properties and Anti-inflammatory Effects of the Hydroethanolic Extracts of Two Varieties of Bayberry fruit (Myrica rubra Sieb et Zucc.) Prepared by Stirring and Ultrasonic Methods

Abstract

Chinese bayberry (Myrica rubra Sieb. et Zucc.) is an economically important medicinal plant with multiple uses. Two varieties ‘Dongkui Oriental Pearl’ (Dongkui for short) and acuminata ‘Nakai’ (Nakai for short) were used to compare and evaluate the antioxidant activities of hydroethanolic extracts of the fruit using ultrasonic and stirring extraction methods. Dongkui bayberry fruit extract (BFE) prepared using the ultrasonic method exhibited a significantly higher value for the total phenolic content (TPC) and had lower 50% inhibitory concentration (IC50) values of scavenging activities against 1,1-diphenyl-2- picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and hydrogen peroxide (H2O2), as well as reducing power compared to the other treatment. The TPC of the BFE was significantly correlated with its DPPH, ABTS, and H2O2 radical-scavenging and reducing power activities. Dongkui BFE at a concentration of 0.25 mg/mL exhibited significantly greater protection of RAW 264.7 mouse macrophages against H2O2-induced damage and lipopolysaccharide (LPS)-stimulated nitric oxide production by macrophages, and it displayed remarkable inhibitory effects compared to the other extracts using the ultrasonic extraction method. Furthermore, compared to the Nakai BFE, macrophages exposed to the Dongkui BFE by the ultrasonic extraction method significantly inhibited LPS-induced production of tumor necrosis factor-α at a concentration of the extract of 0.25 mg/mL. The antioxidant properties and anti-inflammatory and protective effects of BFE prepared by stirring and ultrasonic methods are discussed for the first time in this study