In vitro activities of crude extracts and triterpenoid constituents of Dichapetalum crassifolium Chodat against clinical isolates of Schistosoma haematobium

Mary Anti Chama; Henry Akwaffo Onyame; Claudine Fleischer; Dorcas Osei-Safo; Reiner Waibel; Joseph Otchere; Ivan Addae-Mensah; Michael Wilson

doi:10.1016/j.heliyon.2020.e04460

In vitro activities of crude extracts and triterpenoid constituents of Dichapetalum crassifolium Chodat against clinical isolates of Schistosoma haematobium

Heliyon. 2020 Jul 28;6(7):e04460. doi: 10.1016/j.heliyon.2020.e04460. eCollection 2020 Jul.

Authors

Mary Anti Chama¹, Henry Akwaffo Onyame¹, Claudine Fleischer¹, Dorcas Osei-Safo¹, Reiner Waibel², Joseph Otchere³, Ivan Addae-Mensah¹, Michael Wilson³

Affiliations

¹ Department of Chemistry, School of Physical and Mathematical Sciences, P.O Box LG 56, University of Ghana, Legon, Ghana.
² Department of Chemistry and Pharmacy, Friederich Alexander University of Erlangen-Nurnberg, Schuhstrasse 19, 91052 Erlangen, Germany.
³ Parasitology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.

Abstract

Dichapetalum crassifolium Chodat (Dichapetalaceae) is widely distributed in Africa, Tropical Asia and Latin America. As part of our quest for potential bioactive lead compounds for various neglected tropical diseases, we report the anti-schistosomal potential of the crude extracts and chemical constituents of the stems and roots of Dichapetalum crassifolium. Column chromatography of extracts of the stems and roots led to the isolation and identification of three oleanane-type triterpenoids, friedelan-3β-ol (1), friedelan-3-one (2), and maslinic acid (3); the ursane-type tritepenoid, pomolic acid (4) and the dammarane-type tetracyclic triterpenoids, dichapetalin A (5) and dichapetalin M (6). Dichapetalin A was isolated from only the roots. Isolated compounds were identified by comparison of their physico-chemical and spectral data with published data. The highest in vitro anti-schistosomal activity (IC₅₀) of the crude extracts against clinical isolates of Schistosoma haematobium (Bilharz 1852) was 248.6 μg/ml for the ethyl acetate extract of the root while dichapetalin A gave the highest activity at 151.1 μg/ml among the compounds compared with the 15.5 μg/ml for the standard drug, praziquantel. The rest of the compounds showed activities in the order 177.9, 191.0, and 378.1 μg/ml respectively for mixture of β-sitosterol/stigmasterol, dichapetalin M and friedelan-3-one. The least active extract was the methanol extract of the stem (893.7 μg/ml). The constituents of D. crassifolium showed activity against the S. haematobium that are below praziquantel. It is envisaged that the presence of multiple layers and the minute sizes of pores in the egg shells, may preclude penetration of eggs by the compounds.

Keywords: Dichapetalin A; Dichapetalin M; Dichapetalum crassifolium; Maslinic acid; Natural product chemistry; Organic chemistry; Pharmaceutical chemistry; Pomolic acid; Schistosoma haematobium.