In vitro antioxidant and antiarthritic effects of Persicaria lanigera R. Br. Soják (Polygonaceae) leaf extract in complete Freund’s Adjuvant-induced rheumatoid arthritis model via immunomodulatory regulation of NF-κB, IL-1β, TNF-α, and COX-2 signalin

Rheumatoid arthritis is an autoimmune disease with a high prevalence rate globally, particularly in developing countries. Persicaria lanigera is used in folkloric medicine to treat arthritis and other inflammatory disorders. The present study appraises the potential antioxidant activity and management of arthritis using aqueous ethanol leaf extract of Persicaria lanigera in a CFA-induced arthritis model. The ex-vivo antioxidant activity of the extract was carried out in TAC, DPPH, and H 2 O 2 experiments. Furthermore, in a CFA-induced arthritis model, the antiarthritic effect of Persicaria lanigera extract (100-600 mg kg -1 , p.o. ) was studied by intraplantar injection of 100 µl CFA into right hind limbs of Sprague-Dawley rats (n=7). In this study, P. lanigera exhibited an increase of 39.13±6.80 µg ascorbic acid equivalent per g in TAC and exerted high scavenging effects of 81.87±8.25% and 0.03±0.01 ( p<0.05 ) when compared to ascorbic acid in DPPH and H 2 O 2 respectively. In the CFA-induced model, P. lanigera extract substantially lowered the mean percentage maximal arthritic paw from 854.50±67.00% to 568.50±91.18%, 545.50±71.88% and 541.83±70.21% ( p<0.05 ) at 100, 300, and 600 mg/kg when given therapeutically, respectively. In addition, P. lanigera extract reduced the total inflamed arthritic paw formed significantly by 20.98%, 27.11%, and 33.45% ( p<0.05 ) at the same doses, respectively. The haematological and biochemical alterations were restored by the extract and weight loss in arthritic rats was prevented. In the histopathological and radiological assessments, P. lanigera extract improved the condition of the ankle joint, inhibited bone and cartilage erosion, and maintained the integrity of bone tissues. Furthermore, P. lanigera extract inhibited NF-κB, IL-1β, TNF-α, and COX-2 signaling pathways, and improved ocular conditions of the arthritic rats. The findings have a relevant impact on the development of newer and alternative treatment sources for the management of rheumatoid arthritis as well as other related chronic inflammatory disorders. Ultimately, this study provides vital scientific evidence to support the folkloric use of the plant in traditional medicine for treating inflammatory diseases. Persicaria lanigera extract possesses antioxidant and arthritic properties.