ABSTRACT
From the results of an ethnomedicinal investigation of plants from Uganda with antimalarial activity, Citropsis articulata was selected because of the antiplasmodial effect of an ethyl acetate extract of its root bark. Thus, from the cyclohexane, ethyl acetate, and methanol extracts, two new heterocyclic compounds, omubioside (1) and katimborine (2), were isolated in addition to five known coumarins (rutarin (3), seselin (4), suberosin (5), demethylsuberosin (6), and haploperoside (7)), two known alkaloids (5-hydroxynoracronycine (8) and 1,5-dihydroxy-2,3-dimethoxy-10-methyl-9-acridone (9)), trigonelline (10), and the limonoid 7α-obacunyl acetate (11). The best growth inhibitors of Plasmodium falciparum were alkaloids 8 and 9, with IC50 values of 0.9 and 3.0 µg/mL.
Subject(s)
Antimalarials/isolation & purification , Antimalarials/pharmacology , Coumarins/isolation & purification , Coumarins/pharmacology , Glycosides/isolation & purification , Glycosides/pharmacology , Plasmodium falciparum/drug effects , Rutaceae/chemistry , Alkaloids/chemistry , Alkaloids/isolation & purification , Animals , Antimalarials/chemistry , Chlorocebus aethiops , Coumarins/chemistry , Glycosides/chemistry , Inhibitory Concentration 50 , Leishmania donovani/drug effects , Parasitic Sensitivity Tests , Plant Roots/chemistry , Uganda , Vero CellsABSTRACT
Three structurally related cycloheptapeptides, cyclocitropsides A-C, have been isolated from a MeOH extract of the root bark of Citropsis articulata, a medicinal plant in Uganda. Their sequences were elucidated on the basis of their MS/MS fragmentation, extensive 2D-NMR, chemical degradation, and biochemical modifications. Surprisingly, the sequence of cyclocitropside C differed from that of cyclocitropside B only by an Asp(5)/isoAsp(5) substitution. This is the first report of an isoAsp residue in a plant cyclic peptide.
Subject(s)
Isoaspartic Acid/chemistry , Peptides, Cyclic/chemistry , Plants/chemistry , Rutaceae/chemistry , Amino Acid Sequence , Peptides, Cyclic/isolation & purification , Plant Roots/chemistryABSTRACT
AIM OF THE STUDY: In Uganda, malaria is the most common disease and Ugandan people largely rely on traditional medicine. In this context, we carried out an ethnobotanical study on the Kiohima village, located close to the Kibale National Park in South-Western Uganda and investigated in vitro the antiplasmodial and cytotoxic activities of selected medicinal plants. MATERIALS AND METHODS: Seventy-five plants-using adults (men and women) were interviewed to find out their plant use. From these information, 48 plants used in traditional medicine were identified and according to their reported uses and to bibliographic data, several parts of 28 plants (leaves, barks, roots), were selected and collected for biological evaluations. These samples were dried, extracted with ethyl acetate and the crude extracts were assayed for in vitro antiplasmodial and cytotoxic activities at 10 µg/mL. RESULTS: One third of the screened plants showed a significant antiplasmodial activity with inhibition greater than 50% at 10 µg/mL. CONCLUSION: These results may indicate a possible explanation of the use of some medicinal plant against malaria in the village of Kiohima and have also allowed to highlight a plant with potent antimalarial activity: Citropsis articulata root barks.