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An aqueous two phase system (ATPS) coupled with ultrasonic was employed to extract flavonoids from Cyclocarya paliurus (Batalin) Iljinskaja leaves first time. The optimal conditions were determined by Response Surface Methodology(RSM) of ethanol concentration 33%; salt concentration 15%; extraction time 52 min; liquid‐solid ratio 33:1, while the flavonoids extraction yield obtained the maximum of 3.00 ± 0.1%. The antioxidant activity of flavonoids was evaluated by vitro antioxidant assays under the optimal conditions, which indicated that the extract has strong DPPH, ABTS + and superoxide anion radical‐scavenging activity (IC50 value of 0.0013 mg/ml, 0.0296 mg/ml and 0.126 mg/ml) which were close to and even better than Vc (extremely close to 0, 0.0291 mg/ml and 0.433 mg/ml). The study showed that the ATPS‐ultrasonic was a commendable approach for the extraction of flavonoids from C. paliurus and the flavonoids may serve as new natural antioxidant for functional food ingredients and additives. Practical applications: In this study, ethanol and inorganic salt are selected as the extraction and separation solvent, which is simpler than the traditional method, environmental friendly, while reducing the process cost, and has great application value. Furthermore, through the analysis of the extraction components of the edible plant Cyclocarya paliurus, it was found that the flavonoids contained in C paliurus had antioxidant activity close to vitamin C. Combined with the above research, C. paliurus has the potential to develop into functional food and additives with antioxidant function. [ABSTRACT FROM AUTHOR]

Phyllodiumpulchellum has been traditionally used as a medicinal herb because of its health-promoting effects, such as its hepatoprotective and antioxidant activities. In the present study, the petroleum ether fraction, ethyl acetate fraction, n-butanol fraction, and aqueous fraction were successively obtained from the ethanol extract of P. pulchellum. Two fractions, ethyl acetate fraction and n-butanol fraction, were found to display hepatoprotective and antioxidant activities. Further chemical investigation of the active fractions led to the isolation of its main constituents, including 11 flavonoids (1–11) and 8 indole alkaloids (12–19). There were 9 flavonoids (1–9) that were obtained from the ethyl acetate fraction, and 2 flavonoids (10 and 11) and 8 alkaloids (12–19) from the n-butanol fraction. Compounds 1–11 and 16–19 were isolated for the first time from P. pulchellum, and 1, 2, 8, 11, and 18 were obtained from the genus Phyllodium initially. Subsequently, the isolated compounds were evaluated for their in vitro hepatoprotective effects on the human normal hepatocyte cell line L-O2 injured by d-galactosamine and radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH). The flavonoids (−)-epigallocatechin (5) and (−)-epicatechin (6) exhibited prominent hepatoprotective activities with higher cell viability values (65.53% and 62.40% at 10 μM·mL−1, respectively) than the positive control, silymarin (61.85% at 10 μM·mL−1). In addition, compared with the positive control of vitamin C (IC50: 5.14 μg·mL−1), (−)-gallocatechin (3) and (−)-epigallocatechin (5) exhibited stronger antioxidant activities with IC50 values of 3.80 and 3.97 μg·mL−1, respectively. Furthermore, the total flavonoids from P. pulchellum were characterized using a high-performance liquid chromatography-linear ion trap quadrupole-Orbitrap-mass spectrometry (HPLC-LTQ-Orbitrap-MS). In total, 34 flavonoids were tentatively identified, which had not been previously reported from P. pulchellum. In addition, we performed a semi-quantitative analysis of the isolated flavonoids. The contents of compounds 1–11 were 3.88, 17.73, 140.35, 41.93, 27.80, 4.34, 0.01, 0.20, 9.67, 795.85, and 5.23 μg·g−1, respectively. In conclusion, this study revealed that the flavonoids that were isolated from P. pulchellum showed hepatoprotective and antioxidant activities, indicating that, besides alkaloids, the flavonoids should be the potential pharmacodynamic ingredients that are responsible for the hepatoprotective and antioxidant activities of P. pulchellum. [ABSTRACT FROM AUTHOR]