RESUMO
BACKGROUND & OBJECTIVE: Peganum harmala has been traditionally used to manage rheumatoid arthritis (RA) and other inflammatory conditions. However, its use against RA has not been scientifically evaluated. The current study was designed to assess the anti-arthritic and anti-inflammatory activities of the methanolic extract of P. harmala leaves by in vitro and in vivo methods. METHODS: The in vitro assays were carried out to determine the effect of plant extract on inhibition of egg albumin denaturation and human red blood cell membrane (HRBC) stabilization. Moreover, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity was performed to determine the antioxidant potential. In vivo anti-arthritic activity was performed by determining the curative effect against Complete Freund's adjuvant (0.1 ml). The plant extract was administered to rats orally at 200, 400 and 600 mg/kg/day for 21 days. RESULTS: The values of IC50 of plant extract in protein denaturation, stabilization of HRBC and DPPH assays were 77.54 mg/ml, 23.90 mg/ml and 58.09 µg/ml, respectively. Moreover, the plant extract significantly attenuated the poly-arthritis and weight loss, anemia and paw edema. The plant extract restored the level of C-reactive protein, rheumatoid factor, alanine transaminase, aspartate transaminase and alkaline phosphatase in poly-arthritic rats. Moreover, the plant extract restored the immune organs' weight in treated rats. Treatment with P. harmala also significantly subdued the oxidative stress by reinstating superoxide dismutase, reduced glutathione, catalase and malondialdehyde in poly-arthritic rats. The plant extract notably restored the prostaglandin-E2 and tumor necrosis factor (TNF)-α in the serum of poly-arthritic rats. CONCLUSION: It was concluded that P. harmala extract had potential antioxidant, anti-inflammatory and antiarthritic activities, which primarily might be attributed to alkaloids, flavonoids and phenols.