Z Naturforsch [C]. 2002 Nov-Dec; 57(11-12): 1022-7.

Herbal remedies traditionally used against malaria in Ghana: bioassay-guided fractionation of Microglossa pyrifolia (Asteraceae).

KÃ¶hler I, Jenett-Siems K, Kraft C, Siems K, Abbiw D, Bienzle U, Eich E.

Institut f�r Pharmazie (Pharmazeutische Biologie), Freie Universit�t Berlin, KÃ¶nigin-Luise-Strasse 2+4, D-14195 Berlin, Germany.

Different extracts from 11 West African plants traditionally used against malaria in Ghana were tested against both the chloroquine-sensitive strain PoW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum. Due to the promising in vitro activity of the lipophilic extract [IC50: 10.5 microg/ml (PoW); 13.1 microg/ml (Dd2)], Microglossa pyrifolia (Lam.) Kuntze (Asteraceae) was chosen for further phytochemical investigation. From active fractions 13 compounds were isolated; their structures were established on the basis of spectroscopic methods. 1-Acetyl-6E-geranylgeraniol-19-oic acid and sinapyl diangelate represent new natural compounds. The two diterpenes E-phytol [IC50: 8.5 microM (PoW); 11.5 microM (Dd2)], and 6E-geranylgeraniol-19-oic acid [IC50: 12.9 microM (PoW); 15.6 microM (Dd2)] proved to be the most active constituents in our test system.