Esculentic acid, a novel and selective COX-2 inhibitor with anti-inflammatory effect in vivo and in vitro.

Esculentic acid (EA), a pentacyclic triterpenoids compound extracted from the Chinese herb Phytolacca esculenta, has long been used in traditional Chinese medicine for the treatment of rheumatoid arthritis, edema, hepatitis and bronchitis disease. The present study aimed to investigate the anti-inflammatory effect of EA in vivo and in vitro and the effect of EA on cyclooxygenase (COX) protein expression. To gain insight into the anti-inflammatory effect of EA both in vivo and in vitro and its effect on COX-2 expression, we used animal inflammatory models and lipopolysaccharide (LPS)-induced mouse peritoneal macrophages to examine the anti-inflammatory action of EA. Our findings demonstrated that EA possessed potent anti-inflammatory activity both in vivo and in vitro, while the anti-inflammation action in vitro may be attributed to the inhibition of the level of TNF-α and IL-6 pro-inflammatory cytokines and PGE2 inflammatory mediator in macrophages. Meanwhile, the production of PGE2 was possibly associated with COX-2 protein expression which was similar to that of NSAIDS. The study extends our understanding of the anti-inflammatory effect of EA both in vivo and in vitro and provides clarification of the molecular mechanisms underlying the effect of EA on PGE2 production, extending a novel aspect to the pharmacological activity of EA.