Fig. 2
Gradient reverse phase HPLC analysis of flavonoids in the shoots of A. occidentale and the flavonoid standards. HPLC analysis was performed on the hydrolysed samples of A. occidentale (Fig. 2a) and the flavonoid standards (Fig. 2b). Flavonoids were separated on a NovaPak C18 reversed-phase column (150 × 3.0 mm i.d, 4 μm), using a linear gradient system of 7–40% acetonitrile in water (pH 2.5), at a flow rate of 0.5 ml/min. Absorbance was measured at a wavelength of 260 nm. 1:quercetin; 2:kaempferol