Caralluma tuberculata exhibits analgesic and anti-arthritic potential by downregulating pro-inflammatory cytokines and attenuating oxidative stress.

Caralluma tuberculata N.E. Brown (Common name: Chongan), belonging to the family Asclepiadaceae is distributed widely in hilly areas of Dir, Swat, Kohat and in plain lands of Punjab, Pakistan. The plant has been used as a source of vegetable as well as home remedy for headache, muscle spasms and rheumatism. The present study was proposed to investigate the analgesic, anti-inflammatory and anti-arthritic potential of the aqueous methanolic extract of C. tuberculata (ICE). The dried shoots of plant were used to prepare aqueous methanolic extract (30:70) by 3 days thrice maceration and filtration followed by evaporation under reduced pressure. ICE was screened for the presence of phytochemicals using preliminary phytochemical analysis and HPLC. The antioxidant potential was evaluated through DPPH assay. Analgesic potential of ICE was studied using hot plate and tail immersion methods, and anti-inflammatory activity was performed using turpentine oil and carrageenan-induced inflammation models, in wistar albino rats. Formaldehyde-induced and Complete Freund's Adjuvant-induced arthritis models were used for the assessment of anti-arthritic activity of ICE and its effects on serum levels of PGE-2 as well as gene expression levels of pro-inflammatory cytokines were studied. ICE displayed a dose-dependent (300-1000 mg/Kg p.o.) analgesic effect in hot plate (maximum retention time of 10.87 and 13 s) and tail immersion (response time of 11 and 13.64 s) tests at the doses of 500 and 1000 mg/Kg, respectively. The extract exhibited a significant decrease in paw inflammation of rats at the doses of 500 and 1000 mg/Kg as compared to the disease control group. ICE also exhibited a remarkable decline in arthritic score and a dose-dependent drop in serum levels of prostaglandin E2. There was a significant suppression in the expression of TNF-α, IL-1β, IL-6, NF-κB and cyclooxygenase enzyme in treatment groups. This study concludes that Caralluma tuberculata exhibits strong analgesic, anti-inflammatory, antioxidant and anti-arthritic activities thus upholding the vernacular use of the plant for pain and rheumatism.