Isolation and characterization of betulinic acid from the stem bark of Feretia canthioides Hiern and its antimalarial potential

Background Malaria is a parasitic disease that constitutes a major global health concern and the increasing resistance of Plasmodium falciparum strains to the commonly used antimalarial drugs has resulted in an increase in treatment failures (Zofou et al.,Malar Res Treat: 561342, 2011). Natural products isolated from plants used in traditional medicine have shown promising antimalarial actions in vitro, and these plants can serve as potential sources for new antimalarial drugs (Wright et al.,Phytother Res 8:149–152, 1994); hence, research into the use of medicinal plants for the treatment of malaria would provide viable options in the effective control of the disease by screening plant extracts for antimalarial activities and also isolating bioactive components from these extracts using TLC and column chromatographic techniques. This research was focused on investigating the antimalarial potentials of the stem bark of Feretia canthioides Hiern used in the traditional treatment of malaria in Nigeria. Results In vitro antimalarial tests carried out on the plant extracts and isolated compound in this research revealed that the methanol extract displayed promising antimalarial activities with an inhibitory concentration (IC 50 ) value of 7.76 μg/ml, the n-hexane extract showed low activity with an IC 50 value of 63.10 μg/ml, while the ethyl acetate and dichloromethane extracts were found to be inactive with IC 50 values above 100 μg/ml. The isolated compound (betulinic acid) showed good antimalarial activity with an IC 50 value of 12.60 μg/ml when compared with chloroquine phosphate which served as the positive control. Detailed phytochemical screening of the plant extracts obtained after extraction of the plant material indicated that the methanolic extract of the stem bark of Feretia canthioides Hiern contained major plant secondary metabolites which include tannins, alkaloids, terpenoids, flavonoids, steroids, alkaloids, saponins and glycosides. Chromatographic techniques carried out on the methanolic extract of this plant led to the isolation of a pentacyclic triterpenoid compound identified to be betulinic acid which is been reported for the first time from the methanolic extract of the stem bark of this plant. Conclusion The inhibitory concentration values (IC 50 ) of the methanolic extract and isolated compound in this research prove that this plant can serve as an effective agent for the treatment of malaria. This research concluded that the stem bark of Feretia canthioides Hiern can be further investigated as a prospective antimalarial agent.