Anti-inflammatory and antinociceptive effect of Pachygone ovata leaves

Context: Pachygone ovata (Poir.) Miers ex Hook. F. et Thoms (Menispermaceae) is a rich source of bioactive bisbenzylisoquinoline and aporphine alkaloids.

Objective: This study investigates the in vitro and in vivo anti-inflammatory and antinociceptive potential of Pachygone ovata leaves.

Materials and methods: Lipoxygenase (LOX) assay for anti-inflammatory activity was conducted using MeOH, EA, H and Aq extracts; followed by alkaloid isolation. The anti-inflammatory potential was determined using carrageenan-induced paw oedema and formalin tests for evaluation of Pachygone ovata analgesic effect. Different doses (100, 300 and 400?μg/kg) were administered orally to Wistar rats for a period of one week, once daily.

Results: MeOH and EA extract efficiently inhibited LOX (IC₅₀ 1.43 and 2.15?μg/mL, respectively). MeOH extract had better inhibiting capacity (57%) than indomethacin (51%) in carrageenan induced rats. MeOH extract (300?μg/kg) significantly reduced the increased levels of nitric oxide (8?±?0.57 M), total leukocyte count (4.5?±?0.05 cells 10³/cells) and C-reactive protein (55?±?0.45?mg/mL). There was a decrease in various serum biochemical markers (ALT, AST). Histopathological studies revealed reduction in oedema and decreased cellular infiltration on supplementation with MeOH extract. Furthermore, MeOH extract (300?μg/kg) and alkaloid fraction (400?μg/kg) effected both phases (neurogenic and inflammatory) of formalin injected models.

Discussion and conclusion: Inflammatory mediators play a key role in inflammation; therefore, keeping it in control is of utmost importance. The usefulness of Pachygone ovata leaves on pain and inflammation has been described, probably due to its effect on inflammatory mediators and high alkaloid content.