Curative potential of Populus ciliata Wall ex. Royle extract against adjuvant-induced arthritis and peripheral neuropathy in Wistar rats.

Populus ciliata (PCCR) is traditionally used to treat muscular swelling, inflammation, pain, and fever. The current study was designed to validate the potential of aqueous ethanolic extract of the plant against inflammation, peripheral neuropathy, and pain in arthritic rats. The PCCR was chemically characterized by gas chromatography-mass spectroscopy and high-performance liquid chromatography. In vitro antioxidant, and in vitro anti-inflammatory assays were carried out on PCCR. For anti-arthritic potential, Wistar rats' rear paws were injected with 0.1 ml Complete Freund's Adjuvant using methotrexate (3 mg/kg/week) as standard control. PCCR at 100, 200, and 400 mg/kg was given orally to arthritic rats for 21 days. The PCCR exhibited significant inhibition of bovine serum albumin denaturation (IC-50: 202.1 µg/ml), egg albumin denaturation (IC-50:553.5 mg/ml) and RBC membrane stabilization (IC-50: 122.5 µg/ml) and antioxidant (IC-50 = 49.43 µg/ml) activities. The PCCR notably decreased the paw diameter and increased body weight of treated arthritic animals as equated to diseased control. The treatment notably (p < 0.05-0.0001) decreased malondialdehyde, and increased superoxide dismutase, reduced glutathione, and catalase in the liver and sciatic nerve homogenate in compared to diseased rats. The PCCR treatment remarkably (p < 0.05-0.0001) regulated the levels of nor-adrenaline and serotonin in sciatic nerve in contrast to diseased rats. Treatment with PCCR improved the motor activity, pain, ligament degeneration, and synovial hyperplasia in arthritic rats. Moreover, PCCR significantly (p < 0.01-0.0001) decreased the IL-6 and TNF-α. It is evident from the current study that PCCR had ameliorated polyarthritis and peripheral neuropathy through reduction of inflammatory markers, and improvement of oxidative stress might be due to presence of phenolic acids, flavonoids, phytosterols, and other fatty acids.