Cooperative Interaction of Hyaluronic Acid with Epigallocatechin-3-O-gallate and Xanthohumol in Targeting the NF-κB Signaling Pathway in a Cellular Model of Rheumatoid Arthritis

Abstract

Current intra-articular therapies with hyaluronic acid (HA) provide symptomatic relief in joint diseases, but have limited efficacy in counteracting oxidative stress and in- flammation, key drivers of cartilage degradation in rheumatoid arthritis (RA). To address this limitation, the potential of combining HA with the phytochemicals xanthohumol (XAN) and epigallocatechin-3-O-gallate (EGCG), known for their antioxidant and anti- inflammatory properties, was evaluated in a cellular model of RA (SW982 synoviocytes stimulated with interleukin-1β, IL-1β). The Chou–Talalay method demonstrated that their combination synergistically reduced reactive oxygen species (ROS) and nitric oxide (NO) levels. The “TRIPLE” combination (HA + XAN + EGCG) showed the lowest combination index and the highest dose reduction index. Compared to individual treatments, TRIPLE significantly decreased IL-1β-induced IL-6, IL-8, TNF-α, and MMP-3 levels, while increas- ing the levels of the anti-inflammatory cytokine IL-10. Western blot analysis revealed a marked reduction in iNOS, COX-2, and MMP-3 protein expression following TRIPLE treatment. Moreover, the combination inhibited IL-1β-induced phosphorylation of IκB and p65, thereby preventing NF-κB activation. These findings suggest that integrating XAN and EGCG into injectable HA formulations may represent a promising strategy to improve the management of joint inflammation in RA.