Chemical composition of flavonoids extracted from the leaves of C. paliurus was analysed by LC–MS method (Coppin et al., 2013). Methanol and 0.1% (v/v) formic acid were used as the mobile phase. The elution program was as follows: 0–40 min (30–60 % methanol), 40–60 min (60–80% methanol), 60–70 min (80–30 % methanol). The flow rate was 0.8 mL/min and the injection volume was 5 lL. The UV detector was set at the wavelength of 270 nm and the column temperature was maintained at 30 C. In order to reduce the contamination flow into the ion source, the eluent was discharged to waste for the first 2 min.