The bioactivity of novel furanoterpenoids isolated from Siphonochilus aethiopicus

Aim of the studyThis study investigated the medicinal plant Siphonochilus aethiopicus (Zingiberaceae) for antiplasmodial activity.Materials and methodsThe ethyl acetate extract of Siphonochilus aethiopicus rhizomes was fractionated using solid phase extraction (SPE) and purified by high performance liquid chromatography. Structure elucidation was performed with nuclear magnetic resonance and mass spectrometry. The in vitro cytotoxicity and antiplasmodial activity was determined. In vivo schizontocidal activity was performed in a malaria mouse-model. Additional in vitro testing was done against Staphylococcus aureus, Klebsiella pneumoniae and Mycobacterium tuberculosis.Results and discussionThe ethyl acetate extract showed in vitro activity against the chloroquine-sensitive (CQS) and chloroquine-resistant (CQR) strains of Plasmodium falciparum with IC50-values of 2.9 μg/ml and 1.4 μg/ml, respectively. Bioassay-guided fractionation led to the isolation of three novel furanoterpenoids with moderate in vitro antiplasmodial activity. The crude extract showed very good in vivo activity. The compounds and crude extract were more active against the CQR strain than the CQS strain of Plasmodium falciparum. The SPE fractions were more active than the isolated compounds. The compounds did not show good activity against the micro-organisms tested. No in vitro cytotoxicity was observed.ConclusionThis study provides evidence of antiplasmodial compounds present in Siphonochilus aethiopicus.