HPLC chromatogram of the extraction solvent (a), mixed standards solution (b), P. angulata leaves (c), calyces (d) and fruits (e). All peaks were identified based on the UV spectra theory of phenolic acids and flavonoids developed by Campos and Markham (2007). P1–P13: Phenolic acids, including P4: chlorogenic acid, P6: caffeic acid, P8: p-coumaric acid. F1–F9: Flavonoids, including F4: rutin, F9: queretin.