Development of novel transdermal therapy for rheumatoid arthritis from Adenanthera microsperma Teijsm. & Binn

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by persistent joint inflammation, pain, and progressive cartilage destruction. Current treatments have limitations, necessitating alternative therapeutic strategies. This study evaluated the anti-arthritic potential of Adenanthera microsperma , a species with traditional use in inflammatory conditions [ 1 ]. The in vitro anti-inflammatory potential of the methanolic extract was evaluated in RAW 264.7 macrophages, where it exhibited significant nitric oxide inhibition. Additionally, the extract demonstrated activity in the in vitro anti-arthritic assay using the protein denaturation method. Based on these findings, in vivo studies were performed in female Sprague-Dawley rats with CFA-induced arthritis [ 2 ]. The extract was administered orally at doses of 200 and 400 mg/kg, demonstrating promising anti-arthritic effects. To enhance site-specific delivery and minimize systemic toxicity, a transferosome-based transdermal gel was formulated [ 3 ] and evaluated at 25 mg/kg and 50 mg/kg, with methotrexate gel as the standard. The formulation significantly reduced inflammatory markers: IL-6 (581.03 pg/mL in disease control vs. 219.11 pg/mL at 50 mg/kg), IL-1β (267.97 pg/mL vs. 97.73 pg/mL), and TNF-α (54.77 pg/mL vs. 24.33 pg/mL). X-ray analysis of the affected ankle joint confirmed reduced bone erosion, and histopathology revealed decreased synovial hyperplasia and inflammatory infiltration. Furthermore, oxidative stress markers (SOD, catalase) were significantly restored. The transferosomal gel formulation effectively alleviated arthritis symptoms, offering a targeted, non-invasive therapeutic approach with reduced systemic side effects. These findings establish A. microsperma as a promising natural anti-arthritic agent, warranting further clinical investigation. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany