Publications scientifiques
Michel Arnaud Mbock
Raceline Gounoue Kamkumo
Bruno Ndjakou Lenta
Brice Maxime Nangmou Nkouayeb* (Auteur correspondant)
Hermine Laure Maza Djomkam* (Auteur correspondant)
Georges Bellier Tabekoueng
Willifred Dongmo Tékapi Tsopgni
Anatole Guy Blaise Azébazé
Gabin Thierry M. Bitchagno
Silvère Augustin Ngouela
Marcel Frese
Norbert Sewald
Chemistry & Biodiversity
Abstract The root extract of Nauclea xanthoxylon (A.Chev.) Aubrév. displayed significant 50 % inhibition concentration (IC 50 s) of 0.57 and 1.26 μg/mL against chloroquine resistant and sensitive Plasmodium falciparum ( Pf ) Dd2 and 3D7 strains, respectively. Bio‐guided fractionation led to an ethyl acetate fraction with IC 50 s of 2.68 and 1.85 μg/mL and subsequently, to the new quinovic acid saponin named xanthoxyloside ( 1 ) with IC 50 s of 0.33 and 1.30 μM, respectively against the tested strains. Further compounds obtained from ethyl acetate and hexane fractions were the known clethric acid ( 2 ), ursolic acid ( 3 ), quafrinoic acid ( 4 ), quinovic acid ( 5 ), quinovic acid 3‐ O ‐ β ‐D‐fucopyranoside ( 6 ), oleanolic acid ( 7 ), oleanolic acid 3‐acetate ( 8 ), friedelin ( 9 ), β‐sitosterol ( 10a ), stigmasterol ( 10b ) and stigmasterol 3‐ O‐β‐ D‐glucopyranoside ( 11 ). Their structures were characterised with the aid of comprehensive spectroscopic methods (1 and 2D NMR, Mass). Bio‐assays were performed using nucleic acid gel stain (SYBR green I)‐based fluorescence assay with chloroquine as reference. Extracts and compounds exhibited good selectivity indices (SIs) of >10. Significant antiplasmodial activities measured for the crude extract, the ethyl acetate fraction and xanthoxyloside ( 1 ) from that fraction can justify the use of the root of N. xanthoxylon in ethnomedicine to treat malaria.
