Isolation And Biological Activity Of Anti-endotoxic Compounds In Radix Paeoniae Rubra

Objective: Lipopolysaccharides (LPS), an important part of extracellular membrane of Gram-negative bacteria, is recognized as a key molecule in the pathophysiology of sepsis. Radix Paeoniae Rubra is one of the main anti-inflammatory materials in Chinese herbs. In our previous study an anti-LPS monome compound, Pentagalloyglucose (PGG), has been obtained from Radix Paeoniae Rubra. Because PGG belongs to tannin, the value of its potential medical use might be limited. The study presented is designed to determine the nontannin active component of anti-LPS in Radix Paeoniae Rubra.Methods: (1) The existed technique of biosensor was well improved to screen the effective component of anti-LPS from Radix Paeoniae Rubra. (2) Based on thin-layer chromatography and biosensor, the effective extraction of anti-LPS components was established. (3) The active component of anti-LPS was isolated from Radix Paeoniae Rubra through high performance liquid chromatography(HPLC). (4) The active component of anti-LPS was analyzed so as to determine the nontannin component, and their activities of anti-LPS were evaluated.Results: (1) The technique of biosensor based on the target of Lipid A was superior to the traditional test in screening the active component of anti-LPS from Radix Paeoniae Rubra. It's stable, timesaving and less interfered. (2) Through biosensor, all kinds of Radix Paeoniae Rubra from different areas were screened. The results showed those from Sichuan province contained the largest quantity of active components of anti-LPS. (3) The extraction with ethanol was the best among the three methods. (4) Six active components that could bind Lipid A were isolated from Sichuan Radix Paeoniae Rubra. It was identified the other five components were nontannin except for the fourth one. In vivo and in vitro, it was showed that the first and fourth components could neutralize LPS and inhibit the release of tumor necrosis factor-α from RAW264.7, then significantly protect the mice challenged with lethal-dose LPS from death.Conclusion: Radix Paeoniae Rubra contained six components that could bind Lipid A with high affinity. Except that the fourth component was tannin (PGG), the others were nontannin. Among those nontannin components, the first one could resist LPS most effectively by binding Lipid A with the highest affinity.