Effect of the Arctic terrestrial plant Ranunculus hyperboreus on LPS-induced inflammatory response via MAPK pathways

The Arctic flora hosts a limited number of species due to its extreme environmental conditions which also yield novel and unique secondary metabolites from withstanding plants. Considering a lack of research on bioactivity potential of Arctic flora, Ranunculus hyperboreus, an Arctic plant, was studied for its anti-inflammatory potential as a part of ongoing research on discovering novel natural bioactive products. Solvent-based fractions (H2O, n-BuOH, 85% aq. MeOH, n-hexane) from R. hyperboreus extract were observed to decrease the elevated nitrate amount during the inflammatory response of lipopolysaccharide-induced mouse macrophage RAW264.7 cells. To some extent, treatment with fractions was able to regulate the expression and protein levels of inflammation-related enzymes, iNOS and COX-2, and pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6. The most active fractions, H2O and 85% aq. MeOH, were suggested to exert their effect through suppressed activation of MAPK pathways, especially JNK. Based on the studies of same species, phenolic glycosides were suggested to be the main active ingredients. To our knowledge, this is the first report of any bioactivity of R. hyperboreus which could be a valuable source of natural bioactive agents against inflammation.