Characterization of antioxidant compounds extracted from Citrus reticulata cv. Chachiensis using UPLC-Q-TOF-MS/MS, FT-IR and scanning electron microscope.

Citrus reticulata cv. Chachiensis (CRC) has been widely used in many Chinese medicine prescriptions and developed as various health products. Due to its extensive biological activities, increased interest has focused on CRC as a potential source for the treatment of various diseases. However, there is no systematic and sufficient research on optimization and characterization of ultrasound extraction of antioxidant compounds from CRC up to now. In the present work, three parameters including ultrasonic amplitude (45, 55, 70, 85, 95 %), ultrasonic time (26, 40, 60, 80, 94 min) and ethanol concentration (16, 30, 50, 70, 84 %, v/v) were estimated using central-composite design. Determined optimum conditions, considering four responses (TPC, TFC, DPPH and ABTS) at the same time, were 72 % amplitude, 80 min and 70 % ethanol concentration. The maximum yields were TPC values (145.73 mg GAE/g), TFC values (135.21 mg QE/g), DPPH and ABTS scavenging capacity (87.88 and 76.18 mg TE/g, respectively). 55 phytochemicals were identified in the CRC extract using the UPLC-QTOF-MS/MS, 34 of which were flavonoids, which provided important support for various potential applications of CRC.