Comparison of Active Components, Antioxidant Activity and Pancreatic Lipase Inhibitory Activity in Different Solvent Extracts of Penthorum chinense Leaves

The Penthorum chinense Pursh leaves were rich in active ingredients. The active ingredient content, in vitro antioxidant capacity and pancreatic lipase inhibition ability of P. chinense leaves extracted by different solvents (80% acetone, 80% ethanol, 80% methanol, water) were compared in this study. The results showed that the total phenolic content (250.04 mg/g) extracted by 80% acetone was highest, while both the total flavonoid content (176.96 mg/g and 174.89 mg/g) and total proanthocyanidins content (43.05 mg/g and 42.87 mg/g) extracted by 80% methanol and 80% ethanol were highest. Except for rutin, isoquercitrin, kaempferol-3-O-rutinoside, pinocembrin 7-O-D-glucoside, pinocembrin 7-O-(3''-O-galloy-4'',6''-hexahydroxydiphenoyl)-β-glucoside and thonningianin A, the content of nine phenolic compounds showed insignificant differences among three organic solvent extracts, which were significantly higher than those in water extract (P<0.05). Both 80% ethanol extract and 80% methanol extract showed the strongest DPPH free radical scavenging ability (IC₅₀=42.17 μg/mL and 42.21 μg/mL, P>0.05 ), while 80% acetone extract showed the strongest ABTS⁺ free radical scavenging ability (IC₅₀=48.92 μg/mL) and 80% ethanol extract also showed the strongest ferric reducing antioxidant power. In addition, in vitro pancreatic lipase inhibitory activity of 80% acetone extract (IC₅₀=0.46 mg/mL) was the strongest. Correlation analysis showed that DPPH and ABTS⁺ free radical scavenging ability and pancreatic lipase inhibition ability were significantly or extremely significantly positively correlated with 11 phenolic compounds (P<0.05, P<0.01). Above all, in view of the active ingredient content, in vitro biological activity and solvent toxicity, this study recommend 80% ethanol as the extract solvent of P. chinense leaves, which would provide the theoretical basis for the further development, extraction and utilization of P. chinense leaves.