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

Current intra-articular therapies with hyaluronic acid (HA) provide symptomatic relief in joint diseases, but have limited efficacy in counteracting oxidative stress and inflammation, 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 increasing 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.