In vitro and in vivo anti-inflammatory activity and chemical composition of Renealmia petasites Gagnep

The study aimed to investigate the chemical composition and the anti-inflammatory activity of the hydroethanolic rhizomes, stems, and leaf extracts of Renealmia petasites using in vitro and in vivo assays. The chemical composition of the extracts was characterized in a linear iron trap mass spectrometer. Total phenolic, flavonoid, and tannin content were determined by spectrophotometry analyses. In vitro anti-inflammatory activity was investigated in lipopolysaccharide-stimulated macrophages evaluating the influence on the production of superoxide anion (O₂^-), nitric oxide (NO), and the pro-inflammatory cytokines tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). In vivo effects were determined using the air pouch model in which were inoculated carrageenan and thereafter treated with 50 mg/kg of the hydroethanolic extracts of R. petasites. After 4 and 24 h, the cellular influx, protein exudation, cytokines, and nitric oxide were evaluated. Eight compounds were tentatively identified in the R. petasites extracts, suggesting five diarylheptanoids, one flavonoid, and two fatty alcohols. The in vitro results showed that the extracts were capable of blocking free radicals and/or inhibiting their intracellular actions by inhibiting the production of important mediators of the inflammatory process, such as NO, O₂^-, TNF-α, and IL-6. In vivo, R. petasites significantly decrease the influx of leukocytes, mainly neutrophils, protein exudation, NO, TNF-α, and IL-6 concentration in the air pouch model. The results evidenced that R. petasites can be considered a promising alternative therapy for the treatment and management of osteoarthritis and other inflammatory diseases.