Anti-inflammatory sesquiterpene lactones from Tithonia diversifolia trigger different effects on human neutrophils

Abstract The tagitinins isolated of Tithonia diversifolia (Hemsl.) A. Gray, Asteraceae, are the most studied sesquiterpene lactones due to their wide spectrum of pharmacologic activities, especially related with nuclear factor-kappa B inhibition. Nevertheless, detailed studies about the mechanism of action of its active compounds are still lacking. Neutrophils perform a fundamental role in the inflammatory response to several etiologic factors. However, the effect of tagitinins on human neutrophil is not yet clearly known. We investigated the role of tagitinin C (1), tagitinin F (2) and tagitinin A (3) in activation and survival of human neutrophils to establish possible effects in their mechanisms of inflammation. Human neutrophils were purified from the peripheral blood and cultivated with tagitinins C (1), F (2) and A (3) in the presence or not of Escherichia coli lipopolysaccharide. The enzymatic activity, apoptosis and secretion of cytokines rate were determined after 18 h. Lipopolysaccharide-induced myeloperoxidase activity of human neutrophils was significantly inhibited only by tagitinin F (2). Apoptosis of neutrophils was increased in the presence of tagitinin C (1), and it occurred independently of the presence of lipopolysaccharide or dexamethasone. Tagitinins C (1), F (2) and A (3) decrease lipopolysaccharide-induced interleukin-6, interleukin-8 and Tumor necrosis factor alpha production by human neutrophils. Together, these results indicate that tagitinins exhibit anti-inflammatory action on human neutrophils. However, tagitinin F (2) was the only sesquiterpene lactone that decreased secretion of inflammatory products by neutrophils without inducing neutrophil apoptosis.

Topical anti-inflammatory activity of yacon leaf extracts

Smallanthus sonchifolius (Poepp.) H. Rob. , Asteraceae, known as yacon, is an herb that is traditionally used for the treatment of diabetes in folk medicine. However, recent studies have demonstrated that this plant has other interesting properties such as anti-microbial and anti-inflammatory actions. Thus, the purpose of this study was to evaluate the topical anti-inflammatory property of different extracts prepared from yacon leaves and analyze the role of different chemical classes in this activity. Three yacon leaf extracts were obtained: aqueous extract, where chlorogenic acid derivatives and sesquiterpene lactones were detected; leaf rinse extract, rich in sesquiterpene lactones; and polar extract, rich in chlorogenic acid derivatives. All the extracts exhibited anti-edematogenic activity in vivo (aqueous extract: 25.9% edema inhibition at 0.50 mg/ear; polar extract: 42.7% inhibition at 0.25 mg/ear; and leaf rinse extract: 44.1% inhibition at 0.25 mg/ear). The leaf rinse extract furnished the best results regarding neutrophil migration inhibition, and NO, TNF-α and PGE2 inhibition. These data indicate that both sesquiterpene lactones and chlorogenic acid derivatives contribute to the anti-inflammatory action, although sesquiterpene lactones seem to have more pronounced effects. In conclusion, yacon leaf extracts, particularly the sesquiterpene lactone-rich extract, has potential use as topical anti-inflammatory agent.