Inhibition of COX-2 and PGE2 in LPS-stimulated RAW264.7 cells by lonimacranthoide VI, a chlorogenic acid ester saponin.

Lonimacranthoide VI, first isolated from the flower buds of Lonicera macranthoides in our previous study, is a rare chlorogenic acid ester acylated at C-23 of hederagenin. In the present study, the anti-inflammatory effects of lonimacranthoide VI were studied. Lipopolysaccharides (LPS) induced an inflammatory response through the production of prostaglandin E2 (PGE2), and these levels were reduced when lonimacranthoide VI was pre-administered. Additionally, the mechanism of the anti-inflammatory effects of lonimacranthoide VI was investigated by measuring cyclooxygenase (COX) activity and mRNA expression. The results showed that lonimacranthoide VI inhibited mRNA expression and in vitro activity of COX-2 in a dose-dependent manner, whereas only the higher lonimacranthoide VI concentration possibly reduced COX-1 expression and in vitro activity. Taken together, these results indicate that lonimacranthoide VI is an important anti-inflammatory constituent of Lonicera macranthoides and that the anti-inflammatory effect is attributed to the inhibition of PGE2 production through COX activity and mRNA expression.