Chemical and Biological Investigation of the Stem of Dichapetalum Crassifolium

Abstract

In the present study, the stem of Dichapetalum crassifolium was investigated for its phytochemical constituents and their biological properties. The petroleum ether extract yielded friedelan-3-one, friedelan-3β-ol and a mixture of friedelan-3-one and friedelan-3β-ol. The ethyl acetate extract yielded pomolic acid, dichapetalin M and maslinic acid as well as the friedelins and a mixture of β-sitosterol and stigmasterol. No solid was isolated from the methanol extract. These compounds were identified and characterized using comparative thin-layer chromatography, comparative melting point, mixed melting point, IR, 1H and 13C NMR spectroscopy. In the light of recent investigations suggesting that the dichapetalins and some other triterpenoids have a broad spectrum of biological activities coupled with the urgent need of potential anti-schistosomal agents, the crude extracts as well as three isolates; friedelan-3-one, β-sitosterol/stigmasterol and dichapetalin M were screened for their potential egg hatch inhibition activity against Schistosoma mansoni and Schistosoma haematobium. The petroleum ether, ethyl acetate and methanol crude extracts gave IC50 values of 443.7 ± 0.04, 638.0 ± 0.08 and 893.7 ± 0.08 μg/ml respectively. Among the tested isolates, friedelan-3-one, β-sitosterol/stigmasterol and dichapetalin M gave IC50 values of 378.1 ± 0.23, 177.9 ± 0.10 and 191.0 ± 0.12 μg/ml respectively. The observed egg hatch inhibition activity of the most active isolates, the mixture of β-sitosterol/stigmasterol and dichapetalin M, were however found to be about 11 and 12-fold respectively less potent compared to that of the standard drug, praziquantel (IC50 = 15.47 ± 0.06 μg/ml), used in the study. This study constitutes the first report of the chemical and biological investigation of this member of the family Dichapetalaceae. Among the compounds isolated, maslinic acid is reported for the first time from the plant family.