Anti-nociceptive and Anti-inflammatory Effects of Gmelina arborea Roxb. e x. Sm.

Abstract

Background: The aim of the present study was to evaluate the anti-inflammatory and anti-nociceptive activities of the methanolic extract of Gmelina arborea fruit (GAF) and stem bark (GASB) on egg-albumin induced inflammation and heated plate metal respectively. Methods: 500 g of each of the pulverised samples was extracted with 90% methanol using soxhlet extractor to produce dense mass of methanolic extracts after distillation and kept in a refrigerator at 4 o C until further analysis. The anti-inflammatory activity was determined on fresh egg albumins over 4 h by measurement of rat paw oedema according to established procedure. The anti-nociceptive was evaluated by placing each rat on the heated metal plate (Hot plate) maintained at the temperature of about 50-55 0 C within the restraining plastic cylinder while animals responses were taken over 90 min. Results: Methanolic extracts of G. arborea yielded blackish thick mass and greenish paste viscous extract for the GASB and GAF respectively with percentage yields of 28% and 30% respectively. The yield revealed more extractives in the GAF than GASB. The anti-nociceptive properties of both GAF and GASB shows a relatively time dependent activity as rate of inhibition was high at the 30 th min (at the peak of p<0.001) for all doses except for 100 mg/kg per oral for the GAF. At increased time, the activity of most of the extracts reduced considerably. The eggalbumin induced inflammation was inhibited by the extracts as well in different doses. There were considerable inhibition for the GAF as well as the GASB at a minimum significant value of p<0.05 from the 1 st h to the 4 th h with maximum percentage inhibition (PI) values ranging between 30% to a peak of 70% when compared to the control. The methanolic extract of G. arborea fruit and stem bark showed significant (p<0.05) anti-inflammatory activity. Conclusions: This study has shown that GASB and GAF displayed significant anti-inflammatory effect on paw oedema induced by egg-albumin by inhibiting the release of mediators for the entire 4 h experimental period. The anti-nociceptive actions were also significant when compared with the control.