Marchantin A, a macrocyclic bisbibenzyl ether, isolated from the liverwort Marchantia polymorpha, inhibits protozoal growth in vitro

In vitro anti-plasmodial activity-guided fractionation of a diethyl ether extract of the liverwort species Marchantia polymorpha, collected in Iceland, led to isolation of the bisbibenzyl ether, marchantin A. The structure of marchantin A (1) was confirmed by NMR and HREIMS. Marchantin A inhibited proliferation of the Plasmodium falciparum strains, NF54 (IC50 = 3.41 μM) and K1 (IC50 = 2.02 μM) and showed activity against other protozoan species Trypanosoma brucei rhodesiense, T. cruzi and Leishmania donovani with IC50 values 2.09, 14.90 and 1.59 μM, respectively. Marchantin A was tested against three recombinant enzymes (PfFabI, PfFabG and PfFabZ) of the PfFAS-II pathway of P. falciparum for malaria prophylactic potential and showed moderate inhibitory activity against PfFabZ (IC50 = 18.18 μM). In addition the cytotoxic effect of marchantin A was evaluated. This is the first report describing the inhibitory effects of the liverwort metabolite marchantin A against these parasites in vitro.