Anti-inflammatory triterpenoids from Alchornea cordifolia leaves

The n-hexane extract of Alchornea cordifolia Müll.Arg. leaves has been shown to exhibit a significant and dose dependent inhibition of oedema [1]. In the present investigation, the anti-inflammatory effect of three triterpenoids isolated from the n-hexane extract was evaluated. The pulverized leaves of Alchornea cordifolia were extracted with n-hexane and the crude n-hexane extract (A) precipitated with absolute ethanol to obtain n-hexane residue (A1) and ethanol soluble (A2). Both A1 and A2 were subjected to phytochemical investigation. Column chromatographic separation of A2 on silica gel using mixtures of n-hexane, ethyl acetate and methanol afforded three major triterpenoids A2I, A2II and A2III. These triterpenoids were confirmed with Liebermann – Buchard reaction. The anti-inflammatory effects of the triterpenoids were evaluated using egg-albumen-induced rat hind paw edema as a model of inflammation. A2I (50mg/kg) and A2III (60mg/kg), given intraperitoneally, showed high and significant (p<0.01) activity with percent inhibition of edema values of 73.85 and 49.23 respectively. The activity of A2I (50mg/kg) is comparable to that of Aspirin (100mg/kg). The two compounds also showed dose – dependent inhibition of edema with ID₅₀ of 36.6mg/kg and 52.2mg/kg respectively. In conclusion, the anti-inflammatory effects of the n-hexane extract of Alchornea cordifolia leaves may be attributed to the presence of the triterpenoids A2I and A2III.

Acknowledgments: The authors are grateful to Mr. Ozioko of Bio-resource Development and conservation centre, Nsukka, Enugu State, Nigeria, for authenticating the plant material.

References: [1] Osadebe, P.O., Okoye, F.B.C. (2003). J. Ethnopharmacol. 89: 19–24