Journal of Ethnopharmacology 120 (2008) 382–386 Contents lists available at ScienceDirect Journal of Ethnopharmacology journal homepage: www.elsevier.com/locate/jethpharm Screening of medicinal plants from Reunion Island for antimalarial and cytotoxic activity M.C. Jonville a,∗ , H. Kodja b , L. Humeau b , J. Fournel b , P. De Mol c , M. Cao a , L. Angenot a , M. Frédérich a a Université de Liège, CIRM, Laboratoire de Pharmacognosie (B36), Av de l’Hôpital, 1, 4000 Liège, Belgium Université de la Réunion, UMR PVBMT, Av René Cassin, 15, BP7151, 97717 Saint Denis, France c Université de Liège, CIRM, Laboratoire de Microbiologie Médicale (B23), Av de l’Hôpital, 1, 4000 Liège, Belgium b a r t i c l e i n f o Article history: Received 30 May 2008 Received in revised form 4 September 2008 Accepted 5 September 2008 Available online 18 September 2008 Keywords: Malaria Plasmodium Aphloia theiformis Terminalia bentzoe Nuxia verticillata Reunion Island a b s t r a c t Aim of the study: Nine plants from Reunion Island, selected using ethnopharmacology and chemotaxonomy, were investigated for their potential antimalarial value. Materials and methods: Thirty-eight extracts were prepared by maceration using CH2 Cl2 and MeOH, and were tested for in vitro activity against the 3D7 and W2 strain of Plasmodium falciparum. The most active extracts were then tested for in vitro cytotoxicity on human WI-38 fibroblasts to determine the selectivity index. Those extracts were also investigated in vivo against Plasmodium berghei infected mice. Results: Most active of the extracts tested were the dichloromethane leaves extracts of Nuxia verticillata Lam. (Buddlejaceae), Psiadia arguta Voigt. (Asteraceae), Lantana camara L. (Verbenaceae), the methanol extracts from Aphloia theiformis (Vahl) Benn. (Aphloiaceae) bark, and Terminalia bentzoe L. (Combretaceae) leaves displaying in vitro IC50 values ranging from 5.7 to 14.1 ␮g/ml. Extracts from Psiadia, Aphloia at 200 mg/(kg day) and Teminalia at 50 mg/(kg day) also exhibited significant (p < 0.0005) parasite inhibition in mice: 75.5%, 65.6% and 83.5%, respectively. Conclusion: Two plants showed interesting antimalarial activity with good selectivity: Aphloia theiformis and Terminalia bentzoe. Nuxia verticillata still needs to be tested in vivo, with a new batch of plant material. © 2008 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Malaria is still the most common parasitic infection in many tropical and subtropical countries. However, even though efficacious treatments are nowadays widely available, the number of cases in the world has not decreased during the last 30 years. The principal reasons for this situation are the spread of parasite and vector resistance to drugs and insecticides and the cost of some antimalarials, not generally affordable in tropical countries. Thus, new, more affordable or more accessible antimalarial agents possessing original mode of action are urgently needed. There are still many plants that may be of use against malaria that have not been analyzed phytochemically. Plants provide a good source of new compounds and are often already being used by populations that have little access to Western medicine (Newman et al., 2003). Although malaria was declared eradicated from Reunion Island in 1979 according to WHO, plants used to treat malaria could still be found in the local pharmacopoeia. Moreover, imported cases of malaria, from neighboring countries (Madagascar and Comoros ∗ Corresponding author. Tel.: +32 4 366 4336; fax: +32 4 366 4332. E-mail address: MC.Jonville@ulg.ac.be (M.C. Jonville). 0378-8741/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2008.09.005 Island) hit yet by this devastating disease, still occur and traditional remedies are still used to effect a cure. Furthermore, thanks to its geography and its geomorphology (volcanic island), Reunion Island flora is very diverse (up to 30% of vegetation is endemic; Strasberg et al., 2005). For this reason the island is very much worth investigating. We decided to screen flora from this island before the popular knowledge of plant medicine vanishes or the plants themselves disappear. In this study, plants were selected using two strategies. The first one, ethnopharmacology, pointed out several herbal extracts used as a febrifuge or more especially used against paludism in Reunion Island (Lavergne and Véra, 1989; Association Flore Réunion, 2001): Aphloia theiformis (Vahl) Benn. (Aphloiaceae) (native), Terminalia bentzoe L.(Combretaceae) (native), Lantana camara L. (Verbenaceae), Eupatorium triplinerve Vahl (Asteraceae). We also collected other plants notified to treat malaria in Madagascar (the nearest country on the continent) such as Justicia gendarussa Burm f. (Acanthaceae), species of Nuxia and Psiadia (Rasoanaivo et al., 1992). We chose then to harvest two endemic plants from these genera: Nuxia verticillata Lam. (Loganiaceae) and Psiadia arguta Voigt (Asteraceae). The other strategy used was chemotaxonomy. This discipline classifies plants according to their biochemical contents. In agreement with the idea that a class of M.C. Jonville et al. / Journal of Ethnopharmacology 120 (2008) 382–386 compounds could be responsible for a specific pharmacological activity, we decided to pick plants from the Loganiaceae family already being studied in our laboratory for the antiplasmodial activity (Philippe et al., 2005), Buddleja salviifolia (L.) Lam. (Loganiaceae) and Geniostoma borbonicum Spreng. (Loganiaceae) endemic (Forgacs et al., 1981). This paper reports on the antiplasmodial activity (against Plasmodium falciparum in vitro and Plasmodium berghei in vivo) of plants collected on Reunion Island, and on the in vitro cytotoxicity against human cells, WI-38. Our tests were performed with the aim of selecting new plant candidates that might allow us later to isolate antiplasmodial compounds acting on the erythrocytic cycle of the parasite. 2. Materials and methods 2.1. Selection and collection of plant material The plants were collected in various regions of the island (Table 1) and identified by Dr. L. Humeau and J. Fournel (Herbier universitaire de la Réunion). Voucher specimens were deposited in the Herbarium of the Reunion University. The specimens were quickfrozen, pounded with liquid nitrogen and freeze-dried. Batches no. 2 (only) of Nuxia verticillata leaves and Terminalia bentzoe leaves were air-dried at room temperature, with no direct sunlight and then pulverized using an electrical grinder. 2.2. Preparations of extracts For each plant part, 5 g of powdered dried material was macerated three times in 50 ml solvent (MeOH or CH2 Cl2 ), for 30 min with constant shaking, at room temperature. The filtrates were pooled and evaporated to dryness under reduced pressure at 40 ◦ C. 2.3. In vitro antiplasmodial assays Continuous cultures of Plasmodium falciparum, chloroquine sensitive (3D7) and chloroquine resistant (W2) strains, were assessed following the procedure already described in Frederich et al. (2002). Both strains were obtained from Prof. Grellier (Museum d’Histoire Naturelle in Paris, France). Each extract sample was applied in a series of 8 threefold dilutions (final concentrations ranging from 0.09 to 200 ␮g/ml) on 2 rows of a 96-well microplate and was tested in triplicate (n = 3). Parasite growth was estimated by determination of lactate dehydrogenase activity as described previously in Kenmogne et al. (2006). Quinine base (90%, Sigma–Aldrich), chloroquine diphosphate salt (C6628, Sigma–Aldrich), and artemisinin (98%, Sigma–Aldrich) were used as positive controls. 2.4. In vitro cytotoxic assays The human normal fetal lung fibroblasts, WI-38, were maintained in continuous culture in a humid atmosphere at 37 ◦ C and 5% CO2 in DMEM medium (Bio-whittaker-LONZA) supplemented with 10% heat-inactivated foetal bovine serum, 1% l-glutamine (200 mM) and penicillin (100 UI/ml)–Streptomycin (100 ␮g/ml) (Pen-Strep®) (Bio-whittaker-LONZA). For the assays, 96-well microplates were seeded with 200 ␮l medium containing 8000 cells in suspension. After 24 h incubation, cells were treated with 6 threefold dilutions (final concentrations ranging from 0.82 to 200 ␮g/ml) of crude extracts in culture medium. After 48 h incubation, cell viability was determined by adding WST-1 (Roche) tetrazolium salt as a cytotoxicity indicator and by reading absorbance at 450 nm with a scanning multiwell spectrophotometer after about 1-h wait. Tetrazolium salts are 383 cleaved to formazan dye by cellular enzymes (only in the viable cells). The level of absorbance directly correlates to the metabolically active cells. Each condition was realized in triplicate in a 96-well microplate and each set of tests was performed twice. Camptothecin (∼95% HPLC, Sigma–Aldrich) was used as a positive control. 2.5. In vivo antiplasmodial assays The present work was approved by the Ethical Committee for using animals at the University of Liège (no. 79). The test protocol was based on the 4-day suppressive test of Peters (Fidock et al., 2004). Female Swiss mice (10 weeks of age, 25 ± 2 g) obtained from Charles River Laboratories (Brussels) were infested by the rodent parasite Plasmodium berghei NK173 following the protocol described in Frederich et al. (2004) and randomly divided into five mice per group. The treatment doses (50 mg/kg and 200 mg/kg in 7% Tween 80 and 3% ethanol) were given intraperitoneally (200 ␮l/mouse) 4 h after infection on day 0 and were repeated once daily for 3 days. The 200 mg/kg dose of Aphloia methanolic extract was given orally because the suspension was partially soluble. On day 4 and day 7 post-infection, thin blood smears were made from mouse-tail blood and stained with Giemsa. Slides were inspected under microscope and parasitaemia was determined by counting at least 500 erythrocytes. Mice were controlled for their mortality during 2 weeks. Chloroquine diphosphate salt at 2 mg/kg and 4 mg/kg doses was used as a positive control and physiological serum was used as a negative control. 2.6. Statistics Differences between control and the test sample results obtained for in vivo assays were analyzed by the Student t-test. Statistical significance between treatments was set at p < 0.0005. 3. Results In order to conduct a first selection for prospective antiplasmodial recourses, 38 plant extracts (MeOH and CH2 Cl2 ) were investigated in vitro against the 3D7 chloroquine sensitive strain of Plasmodium falciparum. IC50 values were calculated from a set of eight concentrations tested for each extract. Extracts having IC50 values higher than 50 ␮g/ml were discarded, while lower values were summarized and presented in Table 2. According to WHO guidelines and previous results from our team (Philippe et al., 2005; Pink et al., 2005), antiplasmodial activity was classified as follows: highly active at IC50 < 5 ␮g/ml, promising at 5–15 ␮g/ml, low at 15–50 ␮g/ml and inactive at >50 ␮g/ml. The extracts displaying IC50 values < 50 ␮g/ml were tested against the W2 chloroquine resistant strain to confirm their activity (Table 2). Based on the antiplasmodium promising activity (IC50 < 15 ␮g/ml), six extracts, coming from five different species, were picked for further investigations. Cytotoxic assays were performed on human lung fibroblasts to check that the selected extracts were specific to the parasite. The impact of the toxicity was established by analyzing the selectivity index (SI) values. The SI corresponds to the ratio between cytotoxic IC50 values and W2 parasitic IC50 values. The only extract having a very small SI is the one corresponding to Psiadia arguta dichloromethane extract showing a SI = 1.9. The others showing higher selectivity should offer the potential of specific and safer therapy. As a complement to in vitro assays, in vivo tests on mice infected by Plasmodium berghei were carried out. Those assays involve the pharmacokinetic or metabolic process and could show other side 384 M.C. Jonville et al. / Journal of Ethnopharmacology 120 (2008) 382–386 Table 1 Selected plants from Reunion Island used to treat fever and malaria. Local names, populations, sampling dates, voucher numbers and specific parts of the plants used were also indicated. Species (Family) Local name Population (altitude) Date Voucher number Plant parta Aphloia theiformis (Vahl) Benn. (Aphloiaceae) Change écorce, Goyave marron Plaines des Fougères (1200 m) La montagne (650 m) September 2006 REU 04618 L (batch 1) September 2006 REU 04618B L (batch 2), B Buddleja salvi folia (L.) Lam (Loganiaceae) n.d. September 2006 n.d. F, L, B Eupatorium triplinerve Vahl (Asteraceae) Ayapana Plaine des Fougères (1200 m) Saint-André (100 m) January 2007 REU 05708 AP Geniostoma borbonicum Spreng. (Loganiaceae) Bois de piment Plaine des Palmistes (1000 m) Grand Etang (500 m) June 2006 REU 04549 B, L (batch 1) September 2006 REU 04549B L (batch 2) Justicia gendarussa Burm f. (Acanthaceae) Ayapana marron Saint-André (100 m) January 2007 REU 04625 AP Lantana camara L. (Verbenaceae) Galabert, corbeille d’or La montagne (650 m) La montagne (650 m) September 2006 September 2006 REU 02781 REU 02781B L (batch 1) “pink flower” L (batch 2) “orange flower” Nuxia verticillata Lam. (Loganiaceae) Bois maigre La montagne (650 m) Mare longue (350 m) January 2008 January 2007 REU 4619 REU 04404B L (batch 2), B L (batch 1) Psiadia arguta Voigt (Asteraceae) n.d. Fac de Sciences (75 m) November 2006 REU 05706 L Terminalia bentzoe L. (Combretaceae) Benjoin Fac des Sciences (75 m) Fac des Sciences (75 m) November 2006 March 2007 REU 05705 REU 05705 L (batch 1) L (batch 2) a F = flowers; L = leaves; B = bark; AP = aerial part; n.d. = not determined. effects of the drugs not directly related to parasiticidal and cytotoxic action. The five plants displaying in vitro promising activities were tested on mice at 50 mg/kg and 200 mg/kg, except for Nuxia verticillata because of a lack of plant material. Viability and parasitaemia inhibition, displayed in Table 3 and Fig. 1, respectively, are two parameters to consider in that kind of assay. Usually mice infected by Plasmodium berghei die after 7 or 8 days post-infection without any treatment. Apparently, the methanolic extract of Terminalia at 200 mg/kg seemed to be toxic for the mice; 60% died after two injections and the remaining 40% showed locomotion disorders. At lower dose levels, the extract was less toxic, no disorder was detected and a good effect on parasitaemia was noticed especially on day 7 post-infection with a value of 83.5% inhibition (p < 0.0001). The same improvement in parasitaemia inhibition was observed with the extract of Aphloia and Psiadia also on the seventh day post-infection, higher doses displaying 65.6% (p < 0.0005) and 75.5% (p < 0.0002) inhibition, respectively. The significant reduction of parasitaemia on day 7 for those extracts compared to the negative control is indicative of an interesting antimalarial potential. The other promising effect of Terminalia (50 mg/kg) and Aphloia (50 and 200 mg/kg) extracts was viability, which was 60% at the end of the experiment time (day 15 post-infection) compared to the negative control (0% viability at day 15). Table 2 Selectivity index (SI), in vitro IC50 values under 50 ␮g/ml against Plasmodium falciparum and IC50 values against WI-38 cells. Species Plant part Extract 3D7, IC50 (␮g/ml) W2, IC50 (␮g/ml) WI-38, IC50 (␮g/ml) SI Aphloïa theiformis Bark MeOH CH2 Cl2 CH2 Cl2 13.3 ± 0.8 16.1 ± 2.7 21.0 ± 1.6 11.0 ± 3.1 18.2 ± 2.7 22.7 ± 2.9 58.3 ± 5.5 n.d. n.d. 5.3 n.d. n.d. Psiadia arguta Leaves MeOH CH2 Cl2 22.4 ± 2.2 10.1 ± 1.2 26.1 ± 6.5 8.4 ± 1.1 n.d. 16.3 ± 6.3 n.d. 1.9 Terminalia bentzoe Leaves—batch 1 Leaves—batch 2 MeOH CH2 Cl2 MeOH f.p. MeOH CH2 Cl2 24.8 ± 4.9 47.9 ± 1.5 12.8 ± 2.9 25.1 ± 5.2 42.7 ± 3.2 49.1 ± 6.8 n.d. 12.8 ± 3.5 26.2 ± 0.8 21.0 ± 2.1 n.d. n.d. 133.4 ± 26.2 115.5 ± 22.9 n.d. n.d. n.d. 10.4 4.4 n.d. Buddleja salviifolia Bark Leaves CH2 Cl2 CH2 Cl2 49.9 ± 9.6 29.7 ± 12.6 n.d. 18.6 ± 5.8 n.d. n.d. n.d. n.d. Nuxia verticillata Leaves—batch 1 Leaves—batch 2 CH2 Cl2 MeOH CH2 Cl2 MeOH CH2 Cl2 26.7 ± 9.8 32.7 ± 7.4 10.9 ± 1.8 36.9 ± 5.7 27.4 ± 6.6 19.6 ± 7.0 n.d. 8.8 ± 1.2 n.d. n.d. 70.9 ± 12.8 n.d. 33.7 ± 6.5 n.d. n.d. 3.6 n.d. 3.8 n.d. n.d. CH2 Cl2 CH2 Cl2 8.7 ± 1.0 14.1 ± 8.4 5.7 ± 1.6 12.2 ± 2.9 69.5 ± 12.1 97.2 ± 2.4 12.2 7.9 0.062 0.013 0.006 n.d. n.d. 0.369 0.003 n.d. n.d. n.d. n.d. 0.041 n.d. n.d. n.d. n.d. Leaves—batch 1 Bark—batch 2 Lantana camara Quinine Chloroquine Artemisinin Camptothecin Leaves—batch 1 Leaves—batch 2 f.p. = freshly prepared; n.d. = not determined; bolded IC50 values express promising therapeutic activity. M.C. Jonville et al. / Journal of Ethnopharmacology 120 (2008) 382–386 385 Table 3 Effect of selected medicinal plants extracts on Plasmodium berghei in mice. Group (n = 5) Day 4a Parasitaemia (%) Viability (%) Parasitaemia (%) Viability (%) Viability (%) To (n = 10) Chl 2 Chl 4 Aphloia 50b Aphloia 200b Psiadia 50c Psiadia 200c Terminalia 50d Terminalia 200d Lantana 50e 54.4 31.8 1.2 55.0 33.2 50.8 40.5 40.0 48.4 52.0 100 100 100 100 100 100 100 100 40 100 ND 48.5 13.7 39.4 18.7 25.6 13.3 9.0 ND ND 20 80 100 60 60 60 60 60 0 0 0 80 100 60 60 0 0 60 0 0 a b c d e Day 7a Day 15a Post-infection. Park methanolic extract. Pichloromethane extract. Batch 2 methanolic extract. Batch 2 dichloromethane extract. Fig. 1. Results of in vivo assays on parasitaemia inhibition in mice infected by Plasmodium berghei. T0 = negative control; Chl2 = chloroquine, 2 mg/kg; Chl4 = chloroquine, 4 mg/kg; Aphloia 50 = Aphloia theiformis MeOH bark extract, 50 mg/kg; Aphloia 200 = Aphloia theiformis MeOH bark extract, 200 mg/kg; Psiadia 50 = Psiadia arguta CH2 Cl2 extract, 50 mg/kg; Psiadia 200 = Psiadia arguta CH2 Cl2 extract, 200 mg/kg; Term 50 = Terminalia bentzoe MeOH leaf extract, 50 mg/kg; Term 200 = Terminalia bentzoe MeOH leaf extract, 200 mg/kg; Lantana 50 = Lantana camara CH2 Cl2 leaves extract, 50 mg/kg. 4. Discussion Tropical flora is less known and more seriously threatened with extinction than other flora in the world. To prevent the extermination of valuable species it is important to report the usefulness of plants in medicine and to demonstrate that usefulness scientifically. Furthermore, various parameters such as localization and period of collection, plant part, drying procedure and extract preparation may modify the pharmacological response produced by a single species. In this survey, we found that important differences in pharmacological response, as measured in our in vitro antiplasmodial assays, were connected with variations in such parameters. For instance, Aphloia theiformis leaves were collected in two different ecosystems. The methanolic extract from “La montagne” (Table 1) at lower altitude (650 m asl), situated in disturbed leeward submountain rainforest was completely inactive against Plasmodium falciparum, but the specimen from the “Plaine des Fougères”, a native windward submountain rainforest at 1200 m asl, showed a low activity. The part of the plant used is also significant; in this case the bark exhibited higher activity than the leaves. This species which is the only one of the Aphloiaceae family, is a small shrub characterized by a distinctive bark-peeling and by a heterophylly which is indicated by a number of synonyms for the species’ name: Lightfootia theiformis Vahl = Prockia theiformis (Vahl) Willd = Ludia heterophylla Lam. = Neumannia theiformis (Vahl) A Rich. It has a restricted geographical distribution (East Africa, Madagascar, Seychelles and Mascareignes Archipelagos). Traditionally used in Reunion to treat fever, pains, paludism, inflammation, and as a depurative; the leaves are also used in Mauritius as a febrifuge. In Madagascar (Rasoanaivo et al., 1992), the bark is used as an emetic; the young leaves are effective against haematuria and the old leaves against rheumatisms (Lavergne, 1983). Little phytochemical research has been carried out, reporting the presence in the leaves polar extracts of saponins and a xanthone (aphloiol). Besides, aphloiol is known to prevent the lysis of red blood cells (Lavergne, 2004). Another example of a variable response to antiplasmodial assays was obtained with dichloromethane leaves extract of Nuxia verticillata. In this case, the drying procedure was different; the extract exhibiting a moderate activity was one air-dried at room temperature (batch 2). During this procedure, chemical or enzymatic reactions could occur and the secondary metabolites produced by the plants could be transformed. Nuxia verticillata Lam. is endemic to Reunion and Mauritius islands. The leaves of this tree contain flavonoids, saponins, tannins (Forgacs et al., 1981). Results obtained by recent research on an other representative of this genus against Plasmodium are heartening: triterpenoids have been isolated from an ethyl acetate extract of the leaves of Nuxia sphaerocephala, these compounds exhibited in vitro inhibitory activity against FcB1, the best IC50 values being 1.55 ␮g/ml (Mambu et al., 2006). The methanolic leaves extract of Terminalia bentzoe seems to be unstable; oxidation may occur. In fact, its in vitro antiplasmodial activity depends on the freshness of the extract preparation, and also on the drying procedure. When directly frozen after collection, the extract displays low activity, but on the other hand the potency of freshly prepared extract is increased. Terminalia bentzoe is an endemic tree from Mascareigne archipelago (Mauritius, Reunion and Rodrigues islands) and an endangered species of the island of Rodrigues. Its bark is often used by the local population against diarrhoea and dysentery, and as a sudorific (Lavergne, 1983). Actually, there are no reports on this species for antimalarial activity. However, Terminalia is a well-studied genus especially for antiplasmodial activity because of its traditional use against malaria in different countries of Africa. Numerous species displayed high in vitro activity, usually the bark water extract being the most active: Terminalia macrophtera, IC50 against W2 = 1 ␮g/ml (Sanon et al., 2003); Terminalia glaucescens, IC50 against chloroquine resistant and sensitive strains = 2.34–4.21 ␮g/ml (Mustofa et al., 2000). 386 M.C. Jonville et al. / Journal of Ethnopharmacology 120 (2008) 382–386 Several phytochemical studies explored the phytochemistry of this genus; the most common chemical groups with presumed activity are terpenes, flavonoids, saponins. Lantana camara is a widely studied plant. In fact, it has a broad distribution all over the world and many folk medicinal uses are described against illnesses such as malaria, cancers, chicken pox, measles, eczema, ulcers, asthma. A substantial amount of phytochemical research exists but few have reported antimalarial activity. The leaves extract has been already reported for its in vitro antiplasmodial activity against a chloroquine sensitive strain (D10) with a IC50 value of 11 ␮g/ml (Clarkson et al., 2004). The rootbark non-polar extract also has demonstrated high activity against multidrug resistant K1 strain (Weenen et al., 1990). On the other hand, an in vivo study reports only 8% of inhibition of parasite (Hakizamungu and Weri, 1988) which tallies with our results. Psiadia arguta Voigt. (Syn.: P. trinervia willd.) is an endemic endangered species from Mauritius, and is traditionally used as expectorant on this island. To prevent its extinction, Kodja et al. realized a study on its in vitro micropropagation (Kodja et al., 1998). Preliminary phytochemical screenings have shown the presence of alkaloids, coumarins, flavones and tannins (Govinden-Soulange et al., 2002). An interesting study demonstrated the presence of phenolic compounds, including flavonoids having antimicrobial, antiviral but also cytotoxic activities against human skin fibroblasts (Wang and Hostettmann, 1990). This is in accordance with our cytotoxic results. Since the extracts are a mixture of various compounds, the antiplasmodial activity could be caused by a different class of molecule. To confirm this, the compounds responsible for the activity should be isolated and characterized. Psiadia in vivo results exhibits however a slight toxicity (no survival after 15 days), people should be careful when using the extract of this medicinal plant. 5. Conclusions This preliminary screening revealed five plants, of which three endemic to Reunion and Mauritius Islands, having some appealing in vitro antiplasmodial activities. The cytotoxicity of those plants was evaluated; only Psiadia arguta has a low selectivity index. In vivo antimalarial assays highlight the possible value of Terminalia bentzoe and Aphloia theiformis in Plasmodium inhibition. Further investigations on Nuxia verticillata, Terminalia bentzoe and Aphloia theiformis will be carried out in our laboratory to identify the active antimalarial compounds. Acknowledgements D. Strasberg is gratefully acknowledged for his help in the collection of plant samples. The authors wish also to thank Dr. Alain Chariot for the access to the cell culture facilities and Anne-Françoise Rénert for her help in human cells culture. 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