Anti-inflammatory and membrane-stabilizing stigmastane steroids from Alchornea floribunda Leaves

Okoye, F.B.C. and Osadebe, P.O. and Proksch, P. and Edrada-Ebel, RuAngelie and Nworu, C.S. and Esimone, S.O. (2010) Anti-inflammatory and membrane-stabilizing stigmastane steroids from Alchornea floribunda Leaves. Planta Medica, 76 (2). pp. 172-177. ISSN 0032-0943

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Abstract

Alchornea floribunda (Euphorbiaceae) leaves are widely used in African ethnomedicine for the management of acute and chronic inflammatory disorders. In the present study, bioactivity-guided fractionation led to the isolation of two known (1 and 3) and one new (2) stigmastane steroids from the hexane extract of Alchornea floribunda leaves. The anti-inflammatory activities of these compounds were evaluated using in vitro and in vivo animal models. The compounds 1, 2, and 3 at 50 and 100 µg/ear significantly (p < 0.05) inhibited xylene-induced ear edema in mice in a dose-dependent manner. The topical anti-inflammatory effect of 1 and 2 are significantly (p < 0.05) higher than that of indomethacin and prednisolone. At 20 mg/kg (i. p.), all the compounds significantly (p < 0.05) inhibited acute inflammation induced by subplantar injection of egg albumen in rats. Compound 1 exhibited an anti-inflammatory effect (50.9 % edema inhibition) comparable (p < 0.05) to that of prednisolone (48.0 % edema inhibition) at 3 h. Compounds 1, 2, and 3 (50 µg/mL) significantly (p < 0.05) inhibited heat-induced haemolysis of human erythrocytes in vitro, but had no effect on hypotonicity-induced hemolysis. The compounds were elucidated as (24R)-5α-stigmast-3,6-dione (1), 5α-stigmast − 23-ene-3,6-dione (2), and 3β-hydroxy-5α-stigmast-24-ene (3) by spectral analysis. The results of this study show that these compounds may, in part, account for the anti-inflammatory effect of Alchornea floribunda leaves. This is the first report on the isolation and structure elucidation of these anti-inflammatory steroids from Alchornea floribunda leaves.