Iberis amara extract shows anti-inflammatory activity and endothelium protective effect
Iberis amara extract (STW 6, Steigerwald Arzneimittelwerk GmbH, Darmstadt, Germany) has previously been shown to possess good anti-oxidant and anti-inflammatory activity in vitro. The present study deals with testing it in vivo in models of acute and chronic inflammation. The extract showed dose dependent anti-inflammatory activity in the rat paw carrageenan-induced edema model. In the six-day air pouch model the extract reduced markedly the rise in IL-1β, TNFα and PGE2 as well as oxidative stress biomarkers (total nitrite, malondialdehyde and total anti-oxidant activity) in the exudate induced by injecting carrageenan into the pouch. In the adjuvant-induced arthritis model the extract effectively prevented the development of arthritis when given prophylactically and markedly reduced the inflammation in a curative setting. Furthermore, aortae isolated from rats with adjuvant induced arthritis showed a reduced response to endothelium dependent agonists like acetylcholine but little derangement in endothelium independent responses, such as those to norepinephrine and sodium nitroprusside. Treatment with the extract restored the normal responses to acetylcholine but did not influence those to nitroprusside, indicating a possible endothelium protective effect of the extract. The findings lend further evidence to the strong anti-inflammatory potency of Iberis amara and may prove beneficial in safeguarding the integrity of the endothelium in inflammatory conditions.