The effect of aqueous extract of Malva neglecta on expression of inflammatory biomarkers involved in pain in synoviocytes and THP-1 cells as a model of monocyte/macrophage and human cartilage cells in osteoarthritis

Background: Osteoarthritis is now considered as an active complex of biomechanical, biochemical and cellular processes, not a mere degenerative disorder. Considering the complications of common treatments of osteoarthritis, including non-steroidal anti-inflammatory drug (NSAIDs) and corticosteroids, establishment of new treatments is crucial. This study aimed to explore the effect of Malva neglecta extract on the main inflammatory biomarkers in osteoarthritis. Materials and Methods: Aqueous extract of Malva neglecta, ibuprofen and betamethasone were prepared to investigate their effects on inflammatory biomarkers. Synoviocytes were obtained from the healthy radiocarpal joint cartilage of an 8-month-old Holstein cow. Human monocyte/macrophage (THP-1) cells were also obtained to investigate the effect of Malva neglecta extract on inflammatory agents. Lipopolysaccharide (LPS) was used to induce production of inflammatory cytokines in both cells. Real-time PCR was used to investigate the effect of Malva neglecta extract on expression profile of TNF-α, IL-1β, COX-2, IL-18 and iNOS. Production of NO and PGE2 was also investigated in THP-1 cells. Results: Malva neglecta extract reduced TNF-α, IL-1β, iNOS, IL-18 and COX-2 expression in synoviocytes. Expression of all of these factors was also reduced by the extract in THP-1 cells. Moreover, production of PGE2 and NO in the LPS-induced THP-1 cells was reduced by Malva neglecta extract. Ibuprofen and betamethasone were more effective in reducing inflammatory agents than the extract. Conclusion: According to Malva’s ability to reduce the pro-inflammatory cytokines in the synoviocytes and THP-1 cells, its potential role as a supplement method to common NSAIDs and corticosteroids was confirmed.