Abstract:To track the anti-inflammatory substances in purslane, the lipopolysaccharide-induced RAW264.7 macrophage inflammation model was established, which was guided by the tracer of active substances. The extraction, separation and structural identification of anti-inflammatory substances in purslane were performed by column chromatography (for extraction), silica gel column chromatography (for separation), and preparative high performance liquid chromatography and gas chromatography-mass spectrometry (for analyses). The results showed that the three crude extracts obtained from purslane through sequential extractions with petroleum ether-ethanol, anhydrous ethanol and pure water solvents reduced the secretion of nitric oxide (NO) in the cells to 33.13, 25.83 and 20.53 μmol/L, respectively, with the crude petroleum ether extract exhibiting the strongest inhibitory effect (P<0.05). The petroleum ether phase was further separated into four fractions, with the Fr.1, Fr.2 and Fr.3 fractions had stronger anti-inflammatory effects, though the Fr.1 and Fr.2 fractions contained potential toxic components. Therefore, the Fr.3 fraction was selected for further separation. The Fr.3 fraction was separated through a silica gel column to obtain three fractions. The Fr.3.1 subfraction exhibited the strongest inhibitory effect against the NO secretion (11.80 μmol/L). The Fr.3.1 subfraction was further purified by the preparative liquid chromatography and GC-MS analysis, and the main components of the Fr.3.1 subfraction were identified as stearic acid (47.09%), di(2-ethylhexyl)phthalate (13.21%) and other components. This study established a method for separating and purifying anti-inflammatory substances from purslane, and provides a theoretical reference for the development and utilization of purslane.
