Planta Med 2006; 72 - P_007
DOI: 10.1055/s-2006-949807

Antiprotozoal activity of saponins from Anogeissus leiocarpus (Combretaceae)

M Chaabi 1, S Benayache 2, C Vonthron-Sénécheau 1, 3, B Weniger 1, R Anton 1, A Lobstein 1
  • 1Laboratoire de Pharmacognosie, LC1 UMR 7175, Faculté de Pharmacie de Strasbourg,78 route du Rhin, 67401 Illkirch, France
  • 2Laboratoire de Valorisation des Ressources Naturelles, Route Ain El-Bey. 25000 Constantine. Algérie
  • 3Laboratoire de Biologie et Biotechnologies Marines, Ifremer UMR 100, Université de Caen Basse Normandie, Esplanade de la Paix, 14032 Caen, France

In the frame work of our research on African species presenting antiparasitic activities, we reported previously the good antiprotozoal activity of Anogeissus leiocarpus (DC.) Guill. & Perr. (Combretaceae) [1]. In continuation of our work, we examined the constituents of the bark of this species.

Fractionation of the ethanolic bark crude extract was carried out by combination of gel filtration on Sephadex LH-20 and preparative TLC. Two saponins of oleane type were isolated for the first time from this genus and their structures were established by spectroscopic methods, including 2D-NMR heteronuclear correlation experiments. They were identified as olean-12-en-28-oic acid 2α,3β,19α,23,24-pentahydroxy-β-D-glucopyranosyl ester (trachelosperoside E1) (1) and olean-12-en-28-oic acid 2α,3β,19α,23-tetrahydroxy-β-D-glucopyranosyl ester (arjunglucoside I) (2), both previously isolated from Rudgea viburnioides [2].

A comparison of their antiprotozoal activity shows that (1) has a good antitrypanosomal activity (IC50=1.24µM), without significant cytotoxicity (SI >100).

Structure elucidation of three other saponins and three ellagic acid derivatives are currently under progress.

Data shown are values of duplicate

a Plasmodium falciparum K1 resistant strain; b Leishmania donovani amastigotes; c Trypanosoma cruzi Talahuen strain trypomastigotes; d Trypanosoma brucei rhodensiense STIB 900 strain trypomastigotes; e L6 cells, f SI: selectivity index, ratio of cytotoxic activity on L6 cells to antitrypanosomal activity against STIB 900 strain of T. brucei rhodensiense trypomastigotes.

Samples

In vitro antiprotozoal activity IC 50 (µM)

Cytotoxicity e

Antiplasmodialactivity a

Leishmanicidalactivity b

Antitrypanosomalactivity c

Antitrypanosomalactivity d

IC 50 (µM)

SI f

1

>5

>5

>5

1.24

>150

>100

2

>5

>5

>5

>5

>150

>5

Chloroquine

0.19

-

-

-

-

-

Artemisinin

0.007

-

-

-

-

-

Miltefosin

-

0.47

-

-

-

-

Benznidazole

-

-

1.69

-

-

-

Melarsoprol

-

-

-

0.005

-

-

Podophyllotoxin

-

-

-

-

0.048

-

References: 1. Vonthron-Sénécheau, C. et al. (2003), J. Ethnopharmacol. 87: 221–225. 2. Young, M.C. et al. (1998), J. Nat. Prod. 617: 936–938.