Preparative separation of the flavonoid fractions from Periploca forrestii Schltr. ethanol extracts using macroporous resin combined with HPLC analysis and evaluation of their biological activities.

A preparative separation method using macroporous absorptive resin coupled with high-performance liquid chromatography was developed for the separation of six fractions of the 80% ethanol extract of Periploca forrestii Schltr. The six ethanol fractions (5-95; A, B, C, D, E, and F) obtained were carefully analyzed to locate the corresponding peaks in the high-performance liquid chromatography chromatogram of the total extract, which was established in a previous study. Furthermore, the biological activities, including antioxidant activities, acetyl cholinesterase inhibitory capacities, antihyaluronidase activities, and anti-inflammatory effects, were evaluated in MH7A cells. The results demonstrated that fraction E could significantly prevent oxidation and inhibit hyaluronidase and acetyl cholinesterase. Finally, the main flavonoids in fractions A and E from P. forrestii Schltr. were purified, and the compounds were identified as chlorogenic acid, quercetin-3-O-α-L-arabinopyranoside, and quercetin-7-O-β-D-glucopyranoside. The chemical structures were confirmed by mass spectrometry and nuclear magnetic resonance spectroscopy. Furthermore, the inhibitory effects of these compounds against complete Freund's adjuvant-induced secondary immune arthritis in rats were evaluated.