Anti-inflammatory, analgesic, and anti-immune-mediated polyarthritis activities of topically applied polarity fractions of Clematis florida var. Plena and their underlying mechanisms
Clematis florida var. Plena ( C. florida ) holds significant potential as a topical treatment for immune-mediated polyarthritis (IMPA); however, its active fractions and mechanisms of action remain poorly understood. Given the chemical complexity of herbal remedies, this study adopted a bioactivity- and mechanism-driven approach, focusing on the effects of polarity-based fractions rather than isolated compounds. C. florida was extracted with 70% ethanol and sequentially partitioned into petroleum ether (PE), ethyl acetate (EA), n -butanol (BU), and water (WA) fractions. Phytochemical analysis was conducted to determine the distribution of saponins and flavonoids. Anti-inflammatory and analgesic activities were evaluated using xylene-induced ear edema and acetic acid-induced writhing models, respectively. Therapeutic efficacy was assessed in a rat model of adjuvant-induced arthritis via topical application. Joint tissues were analyzed using H&E and Safranin O–Fast Green staining, immunohistochemistry, and Western blotting to investigate histological changes and signaling pathways (ERK and NF-κB). Phytochemical analysis revealed that the extract is rich in saponins and flavonoids, which exhibit distinct distribution patterns across fractions of varying polarity. All fractions exhibited anti-inflammatory effects in the ear edema model and analgesic activity in the writhing test. In the arthritis model, topical application of the EA, BU, and WA fractions significantly attenuated paw swelling and reduced serum levels of TNF-α, COX-2, rheumatoid factor, and IL-6. Histological staining confirmed partial protection against joint destruction. Mechanistic studies revealed that these fractions enhanced ERK phosphorylation and suppressed NF-κB activation in joint tissues. The EA, BU, and WA fractions of C. florida possess significant topical therapeutic potential against IMPA. The anti-arthritic effects are likely associated with the modulation of ERK and NF-κB signaling pathways. This study elucidates the pharmacodynamic basis of C. florida fractions, positioning them as promising candidates for the development of topical treatments for animal joint disorders.