Macroporous Resin Purification of Phenolics from Penthorumchinense Leaves: Phenolic Identification, Composition Analysis, and Biological Activities

In this study, 20% ethanol elution fraction(PC-20), 40% ethanol elution fraction(PC-40), 60% ethanol elution fraction(PC-60), and 80% ethanol elution fraction (PC-80)of Penthorum chinense polyphenols were obtained using AB-8 macroporous resin . Their in vitro bioactivities were compared to explore potential applications. A comprehensive phytochemical analysis identified 85 compounds, including 16 phenolic acids, 36 flavonoids, 24 hydrolyzed tannins, 7 anthocyanins, and 2 others. The results showed clear ethanol concentration-dependent variations in both compound composition and bioactivity. PC-20 had the highest levels of total polyphenols (418.45 mg/g), proanthocyanidins (84.95 mg/g), and tannins (10.61 mg/g), and also showed the best antioxidant capacity. PC-40 contained the most flavonoids (227.55 mg/g). PC-60 gave the strongest α-glucosidase inhibition (IC50 = 0.79 µg/mL), while PC-20 was most effective against pancreatic lipase (IC50 = 101.06 µg/mL) and also significantly activated the enzymes ADH and ALDH. Overall, PC-20 appears more suitable for applications aimed at antioxidant, anti-obesity, or liver-protective effects, whereas PC-60 is more promising for blood glucose control. This work provides a practical basis for selecting different ethanol fractions of P. chinense polyphenols according to specific functional needs.