Anti–anaphylactic and anti–inflammatory activities of a bioactive alkaloid from the root bark of Plumeria acutifolia Poir

o investigate the anti-anaphylactic, anti-inflammatory and membrane stabilizing properties of plumerianine (compound 1) isolated from the root bark of Plumeria acutifolia Poir. The anti-anaphylactic activity of compound 1 (10, 25 and 50 mg/kg) was studied by using models such as passive cutaneous anaphylaxis, passive paw anaphylaxis and its anti-inflammatory activity against carrageenin induced paw edema and cotton pellet granuloma in albino rats was also investigated using ketotifen and indomethacin as reference drugs. A dose-dependent beneficial effect was observed on leakage of evans blue dye in skin challenged with antigen and on paw anaphylaxis induced by antiserum. The compound 1 also exhibited significant (P<0.01) inhibition of rat paw edema and granuloma tissue formation, including significant protection of RBC against the haemolytic effect of hypotonic solution, an indication of membrane-stabilizing activity. Anti-anaphylactic activity of compound 1 may be possibly due to inhibition of the release of various inflammatory mediators. Anti-inflammatory activity of compound may be related to the inhibition of the early phase and late phase of inflammatory events.