Brine shrimp toxicity and antiplasmodial activity of five Kenyan medicinal plants

The organic extracts of leaves and roots of five plants used for treating malaria in Central, Nairobi and Rift Valley Provinces, Kenya were tested for brine shrimp lethality and in vitro antiplasmodial activity against chloroquine sensitive and resistant strains of Plasmodium falciparum. Of the plants tested, 60% were toxic to the brine shrimp (LC(50)<30 microg/ml) and eight out of ten plant parts (80%) showed in vitro antiplasmodial activity (IC(50)<50 microg/ml). Among the extracts screened, the leaves of Cyathula polcephala had the highest toxicity to the brine shrimp (LC(50)=2.9 microg/ml) while the leaves of Pentas longiflora had the best antiplasmodial activity (IC(50)=11. /ml). The plant extracts with low IC(50) values are potential sources for novel antiplasmodial compounds.     

In vitro antiplasmodial activity of Brazilian Cerrado plants used as traditional remedies

Twenty-seven species of native Brazilian Cerrado plants commonly used by traditional healers to treat malaria and other diseases were collected and 204 hexanic and ethanolic extracts were obtained by maceration. The antiplasmodial activity of the extracts was tested in vitro against a chloroquine resistant strain (FcB1) of Plasmodium falciparum, and cytotoxicity against the cell lines L-6 of rats and MRC-5 of human was evaluated. Thirty-two extracts showed significant inhibition rates of Plasmodium falciparum growth and of these six showed cytotoxicity against the cell lines. The strongest antiplasmodial activity was found for the hexanic extracts of Xylopia aromatica root wood (IC(50)=4.7 microg/ml), Xylopia emarginata root bark (IC(50)=4.9 microg/ml), Casearia sylvestris var. lingua leaves, stem wood and stem bark, and root wood and root bark (IC(50) values from 0.9 to 2.3 microg/ml), and Cupania vernalis leaves (IC(50)=0.9 microg/ml); and for the ethanolic extract of Aspidosperma macrocarpon root bark (IC(50)=4.9 microg/ml). However, the best selectivity towards Plasmodium falciparum was observed for the hexanic root bark extract of Matayba guianensis (IC(50) on Plasmodium falciparum=6.1 microg/ml, SI=16.4 for MRC-5) and the ethanolic root bark extract of Aspidosperma macrocarpon (IC(50) on Plasmodium falciparum=4.9 micro/ml, SI=16.2 for MRC-5).     

Antimalarial activity of crude extracts from nine African medicinal plants

An ethnobotanical study was conducted in Comores (Ngazidja) about plant species used traditionally for the treatment of various diseases, including malaria. Antimalarial activity of 76 vegetal extracts obtained from 17 species traditionally used to treat malaria symptoms, was evaluated in vitro using Plasmodium falciparum chloroquine-resistant strain (W2). Antiproliferative activity was evaluated on human monocytic THP1 cells and the selectivity index of the plant extracts was calculated. The results showed that 10 plant extracts had a moderate activity (5相似文献   

Screening of selected indigenous plants of Cambodia for antiplasmodial activity

The in vitro antiplasmodial activity of 117 aqueous, methanol and dichloromethane extracts derived from different parts of 28 indigenous wild plant species was studied. These plants are commonly used in Cambodian traditional medicine. The plant extracts were tested for in vitro activity against a chloroquine resistant Plasmodium falciparum strain (W2). Nine extracts were moderately active with IC(50) values ranging between 5 and 10 microg/ml, 17 extracts were active with IC(50) values ranging between 1 and 5 microg/ml. These 26 extracts derived from eight plants belong to six families. The most active extracts were dichloromethane and came from Stephania rotunda and Brucea javanica with IC(50) values of 1 microg/ml and a selectivity index > or = 25. It is interesting to note that some aqueous extracts were as active as dichloromethane extracts especially aqueous extracts of Stephania rotunda, Brucea javanica, Phyllanthus urinaria and Eurycoma longifolia with IC(50) values of < or = 4 microg/ml. These results are in agreement with statements of healers on traditional uses of these plants for the treatment of malaria and/or fever. In this study, we report the antiplasmodial potential activity of eight plant species from Cambodia. Among them four are tested for the first time.     

In vitro antiplasmodial activity of medicinal plants native to or naturalised in South Africa

The increasing prevalence and distribution of malaria has been attributed to a number of factors, one of them being the emergence and spread of drug resistant parasites. Efforts are now being directed towards the discovery and development of new chemically diverse antimalarial agents. The present study reports on the in vitro antiplasmodial activity of 134 plant taxa native to or naturalised in South Africa, representing 54 families, which were selected semi-quantitatively using weighted criteria. The plant extracts were tested for in vitro activity against a Plasmodium falciparum strain D10 using the parasite lactate dehydrogenase (pLDH) assay. Of the 134 species assayed, 49% showed promising antiplasmodial activity (IC(50)< or = 10 microg/ml), while 17% were found to be highly active (IC(50)< or = 5 microg/ml). Several plant species and genera were shown for the first time to possess in vitro antiplasmodial activity. These results support a rational rather than random approach to the selection of antiplasmodial screening candidates, and identify a number of promising taxa for further investigation as plant-based antimalarial agents.     

In vitro antiplasmodial activity of callus culture extracts and fractions from fresh apical stems of Phyllanthus niruri L. (Euphorbiaceae): part 2

The ethanolic extracts from fresh apical stems of Phyllanthus niruri L. (Euphorbiaceae) cultured on Murashige and Skoog (MS) medium supplemented with IBA/BAP/Coco nucifera L. milk for 1, 2, 4 and 6 months were phytochemically and biologically investigated and compared with intact plant part and whole plant extracts. Results from the in vitro antiplasmodial testing indicated that the EtOH extract of a 1-month-old callus culture (IC(50) = 16.3 +/- 2.5 microg/ml) exhibited a higher activity than the ethanolic extracts of the fresh apical stem (IC(50) = 18.2 +/- 2.4 microg/ml) and callus cultures of 2-, 4- and 6-months-old (25 microg/ml < IC(50) < 40 microg/ml). These activities were however lower than that displayed by the ethanolic extract of the whole plant (IC(50) < 3 microg/ml). The EtOH extract of 1-month-old callus culture (the most active) was fractionated with solvents of different polarities. Its CH(2)Cl(2) fraction rich in terpenic constituents (IC(50) = 9.2 +/- 3.4 microg/ml) exhibited a higher antiplasmodial activity than its isoamylic alcohol fraction obtained at pH 2-3 (IC(50) = 25.6 +/- 2.3 microg/ml) rich in flavonoids. The activity of these two fractions was lower than that displayed by the same fractions from the whole plant (2 microg/ml < IC(50) < 3 microg/ml). Alkaloidic fractions from the whole plant and 1-month-old callus culture of fresh apical stem were considered as inactive (IC(50) > 100 microg/ml).     

Antiplasmodial activity of selected Sudanese medicinal plants with emphasis on Maytenus senegalensis (Lam.) Exell.

The antiplasmodial activity of plant extracts related to four families was tested on chloroquine sensitive strain 3D7 and chloroquine resistant strain Dd2 of Plasmodium falciparum. The methanolic extract of Harrisonia abyssinica (Simaroubaceae) inhibited Dd2 with IC50 value of 4.7 microg/ml, while in 3D7, the IC50 value was 10 microg/ml. Most of the plants from the family Meliaceae showed highly potent antiplasmodial activity against the two tested strains. Khaya senegalensis, Azadirachta indica and Trichilia emetica showed IC50 values less than 5 microg/ml. The methanolic extract of Annona squamosa (Annonaceae) leaves showed high antiplasmodial activity with IC50 values of 2 and 30 microg/ml on 3D7 and Dd2, respectively. While stem bark showed moderate activity with IC50 values of 8.5 and 120 microg/ml on Dd2. Maytenus senegalensis (Celastraceae) possessed IC50 values of 3.9 on 3D7, 10 microg/ml on Dd2 and had no effect on lymphocyte proliferation even at the highest tested concentration; the IC50 was greater than 100 microg/ml. Liquid-liquid separation of the methanolic extract of M. senegalensis revealed that the dichloromethane extract possessed an IC50 value of only 2.1 microg/ml. Column fractionation of dichloromethane extract gave four fractions and fraction two showed an IC50 value of 0.5 microg/ml. Preliminary phytochemical analysis of dichloromethane fraction revealed terpenoids and traces of phenolic principles but no alkaloid, tannins or flavonoids were detected.     

Antiplasmodial and antiamoebic activities of medicinal plants from Sierra Leone

Crude ethanol extracts of 18 medicinal plants from Sierra Leone, West Africa were examined for antiplasmodial activity against Plasmodium falciparum, using an in vitro microtest. Eleven of these extracts were also screened for in vitro antiamoebic activity against Entamoeba histolytica. Only one plant extract, Triclisia patens (Menispermaceae) showed significant antiplasmodial activity (IC(50) = 8 microg/mL). None of the plant extracts was effective against Entamoeba histolytica.     

In vitro antiplasmodial activity and cytotoxicity of ethnobotanically selected South African plants.

The resistance of Plasmodium spp. to currently used drugs has become a serious problem and efforts are being directed in obtaining new drugs with different structural features. One option favoured is the search for new plant derived antimalarial drugs. Bark and leaves of 20 extracts from 14 South African plant species were tested for in vitro antiplasmodial activity by means of the flow cytometric test. The most active extract of each species giving more than 70% inhibition at 50 microg/ml was selected for determination of IC(50) values. Two extracts had IC(50) values below 2 microg/ml, another seven had IC(50) values between 2 and 5 microg/ml while one had an IC(50) of 10.1 microg/ml. Chloroquine had an IC(50) of 0.043 microg/ml. Cytotoxicities of the five most active extracts at 50 microg/ml were determined with the monkey kidney cell toxicity test and the ID(50) values ranged between 35 and 100 microg/ml.     

Antiprotozoal and cytotoxic activities in vitro of Colombian Annonaceae

Ethnobotanical and chemotaxonomical studies for antiparasitic activity of Colombian Annonaceae were carried out. In vitro antiprotozoal activity of 36 extracts obtained from six different species was determined against promastigotes of three Leishmania species, epimastigotes of Trypanosoma cruzi and both chloroquine sensitive (F32) and resistant (W2) Plasmodium falciparum. Cytotoxic activity was evaluated in U-937 cells. Active extracts were selected according their selectivity index (SI). Extracts from Annona muricata, Rollinia exsucca, Rollinia pittieri and Xylopia aromatica were active against Leishmania spp. and Trypanosoma cruzi showing IC50 values lower than 25 microg/ml. Hexane extract from Rollinia pittieri leaves was the most selective against Trypanosoma cruzi and Leishmania spp. (IS=10 and 16, respectively). The extracts from Desmopsis panamensis, Pseudomalmea boyacana, Rollinia exsucca and Rollinia pittieri showed good antiplasmodial activity (IC50 < 10 microg/ml). No correlation between antiplasmodial activity and inhibition of beta-hematin production was found. The present study gives specific and useful information about antiprotozoal and cytotoxic activities of some Annonaceae extracts. Results presented here also demonstrate which plants and/or plant parts could be useful in the treatment of leishmaniasis, Chagas' disease and malaria.     

Biologically active bisbenzylisoquinoline alkaloids from the root bark of Epinetrum villosum

Methanol and water extracts of the root of Epinetrum villosum (Exell) Troupin (Menispermaceae) were found to exhibit antimicrobial and antiplasmodial activities. Investigation of the active methanol fraction led to the isolation of four bisbenzylisoquinoline alkaloids, i.e., cycleanine, cycleanine N-oxide, isochondodendrine and cocsoline. Structures were established by spectroscopic methods. Cocsoline displayed antibacterial and antifungal activities (MIC values of 1000-15.62 and 31.25 microg/ml, respectively). Isochondodendrine was found to have the most potent antiplasmodial activity (IC50 = 0.10 microg/ml), whereas the IC50 on HCT-116 human colon carcinoma cells was 17.5 microg/ml (selectivity index 175). Cycleanine acted against HIV-2 (EC50=1.83 microg/ml) but was at least 10-fold less active against HIV-1. Cycleanine N-oxide showed no activity towards all tested microorganisms.     

Antiprotozoal and cytotoxic screening of 45 plant extracts from Democratic Republic of Congo

AIM OF THE STUDY: To evaluate in vitro the antiprotozoal and cytotoxic activities of 80% methanol extract from 45 medicinal plants collected in Sankuru (Democratic Republic of Congo) against Trypanosoma brucei brucei, Trypanosoma cruzi and the chloroquine-sensitive Ghanaian strain of Plasmodium falciparum, and MRC-5 cell lines respectively. MATERIAL AND METHODS: Different extracts were obtained by maceration of each plant part used with 80% methanol for 24h. The mixture was filtered and evaporated in vacuo to give corresponding dried extract. The activity against Trypanosoma brucei brucei and Trypanosoma cruzi were performed in 96 well tissue plates each containing 10 microl aqueous plant extract dilutions (100 to 0.01 microg/ml) with 10 microl of the parasite suspension cultured in Hirumi medium supplemented with 10% foetal calf serum, a solution of 2% penicillin/streptomycin (2% P/S) After 4 days incubation with Almar bluea solution, fluorescence was measured at 500 nm emission and 530 nm excitation and results expressed as percentage reduction in parasite compared to control wells. The antiplasmodial activity of was assessed in vitro against the chloroquine-sensitive Ghanaian strain of Plasmodium falciparum cultured in RPMI-1640 medium by the lactate deshydrogenase assay in the presence of plant extracts (50 to 0.01 microg/ml). Cell-lines MRC-5 were cultured in MEM medium supplemented with 20mM l-glutamine, 16.5mM NaHCO(3), 5% foetal calf serum and 2% P/S solution. After 4h incubation, cell proliferation/viability was spectrophotomecally assessed at 540 nm after addition of MTT. In each assay, the IC50 value for each sample was derived by the drug concentration-response curves. RESULTS: The extracts from Alcornea cordifolia leaves, Momordica charantia whole plant, Omphalocarpum glomerata, root bark and Piptadia africanum stem bark showed good antiprotozoal activity against Trypanosoma brucei brucei with IC50 values from 0.7 to 7 microg/ml. Only Piptadenia africanum extract showed a pronounced antiprotozoal activity against Trypanosoma cruzi (IC50=4.0+/-06 microg/ml). The extracts from Alchornea cordifolia, Polyathia swaveleons stem bark, Sapium cornutum stem bark and Triclisia giletii stem bark exhibited a pronounced antiplasmodial activity against P. falciparum Ghanaian strain with IC50 values ranging from 0.5 to 3.0 microg/ml. Piptadenia africanum extract was the most cytotoxic sample (CC50=0.25 microg/ml) with poor selectivity against all selected protozoa (SI<10) while other active extracts did not show a significant cytotoxic effect against MCR-5 cell-lines with good selectivity according to the case. CONCLUSION: These active plant extracts are selected for extensive studies leading to the isolation of active constituents.     

In vitro antiprotozoal activities and cytotoxicity of some selected Cameroonian medicinal plants

Eight extracts from seven selected Cameroonian medicinal plants, traditionally used to treat malaria and other protozoal diseases, were tested in vitro for their antiprotozoal activities against Plasmodium falciparum K1 chloroquine-resistant strain, Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei rhodesiense, protozoa responsible for malaria, visceral leishmaniasis, Chagas disease and African trypanosomiasis, respectively. The most active extract against Plasmodium falciparum K1 strain and Trypanosoma brucei rhodesiense was the methanolic extract of Albizia zygia (Fabaceae) stem bark with IC(50) values of 1.0 microg/ml and 0.2 microg/ml, respectively. Five extracts showed IC(50) values below 5mug/ml against Leishmania donovani, with the methanolic seed extract of Harungana madagascarensis showing the highest activity, but only the methanolic extract of Albizia zygia showed activity against Trypanosoma cruzi. Cytotoxicity and selectivity indexes were estimated for the most active extracts. The best ratio of cytotoxicity to antiplasmodial activity (SI(a)=14) was established for the methanolic leaf extract of Symphonia globulifera (Clusiaceae), while the methanolic stem bark extract of Albizia zygia showed the best ratio of cytotoxicity to antitrypanosomal activity (SI(b)=22.5).     

Antiplasmodial activity of selected sudanese medicinal plants with emphasis on Acacia nilotica.

Twenty-two plant organs from eleven plants comprising five families were extracted and screened for antiplasmodial activity in vitro against Plasmodium falciparum 3D7 (chloroquine sensitive) and Dd2 (chloroquine resistant and pyrimethamine sensitive). Fifty nine percent of plant extracts from 22 extracts exerted activity on P. falciparum strain 3D7 with an IC(50) less than 50 microg/mL, whereas 43% of plant extracts showed an IC(50) value within 50 microg/mL on Dd2 strains. Plant extracts from Gardenia lutea, Haplophyllum tuberculatum, Cassia tora, Acacia nilotica and Aristolochia bracteolata possessed IC(50) values less than 5 microg/mL on both tested strains. Bioassay guided fractionation of A. nilotica revealed that the ethyl acetate extract possessed the highest activity (IC(50) = 1.5 microg/mL). Fraction 2 (R(f) = 0.75) prepared by preparative chromatography showed the highest activity on P. falciparum (IC(50) = 1.7 microg/mL). Phytochemical analysis indicated that the most active phase contained terpenoids and tannins and was devoid of alkaloids and saponins. The effect of plant extracts on lymphocyte proliferation showed low toxicity to the human cells. This plant has been subjected to long term clinical trials in folk medicine and is a promising plant.     

In vitro screening of some Strychnos species for antiplasmodial activity

The antiplasmodial activity of crude extracts of 19 species of Strychnos (Loganiaceae) was assessed in vitro against a chloroquine-susceptible strain of Plasmodium falciparum. For each species, ethyl acetate (EtOAc) extracts were analysed and, for the most active species, methanolic (MeOH) extracts were also tested. Among them, Strychnos variabilis De Wild. seemed to be very promising (inhibitory concentration 50% (IC50) < 5 microg/ml) whereas two other species, Strychnos gossweileri Exell and Strychnos mellodora S. Moore, could be interesting (IC50 < 15 microg/ml) in further antimalarial studies.     

Antileukemic activity of selected natural products in Taiwan

The aim of the present study was to evaluate the antileukemic activity of six chemical classes of pure compounds present in commonly used medicinal plants in Taiwan--such as the genus Plantago. Studies were conducted on a series of human leukemia and lymphoma cell lines. Results showed that water soluble compounds (aucubin, caffeic acid, chlorogenic acid, ferulic acid, p-coumaric acid and vanillic acid) exhibited a weak antileukemic activity (IC50: 26-56 microg/ml, SI: 2-11). On the other hand, water insoluble compounds such as triterpenoids (oleanolic acid and ursolic acid), monoterpene (linalool) and flavonoid (luteolin) possessed strong activity against human leukemia and lymphoma cell lines. Among them, linalool showed the strongest activity against histiocytic lymphoma cells U937 (IC50: 3.51 microg/ml, SI: 592.6) and Burkitt lymphoma cells P3HR1 (IC50: 4.21 microg/ml, SI: 494.1). Ursolic acid was effective against P3HR1 cells (IC50: 2.5 microg/ml, SI: 262.6) and chronic myelogenous leukemia cells K562 (IC50: 17.79 microg/ml, SI: 36.91), whereas oleanolic acid inhibited the growth of P3HR1 cells (IC50: 26.74 microg/ml, SI: 11.37). Luteolin exhibited effective activity against K562 cells (IC50 18.96 microg/ml, SI: 5.14) and P3HR1 cells (IC50: 18.99 microg/ml, SI: 5.13). We conclude that terpenes and flavonoid in commonly used medicinal plants possess strong activity against lymphoma and leukemia cells, especially human lymphoma cells, suggesting the potential use of these compounds for treatment of lymphoma.     

Antibacterial activities and cytotoxicity of terpenoids isolated from Spirostachys africana

Spirostachys africana Sond. stem bark is used traditionally for the treatment of diarrhoea and dysentery in Limpopo Province of South Africa. Bioassay-guided fractionation of ethanolic extract from bark of Spirostachys africana led to the isolation of four known compounds, two triterpenoids, compound 1 [d-Friedoolean-14-en-oic acid (3-acetyl aleuritolic acid)] and compound 2 (Lupeol), and two diterpenes, compound 3 [ent-2,6alpha-dihydroxy-norbeyer-1,4,15-trien-3-one (diosphenol 2)] and compound 4 (ent-3beta-hydroxy-beyer-15-ene-2-one). Isolated compounds were tested for antibacterial activity using micro-dilution method. Compound 1, exhibited minimum inhibitory concentration (MIC) of 50 microg/ml against Staphylococcus aureus, Salmonella typhy, Vibrio cholera, Escherichia coli and Shigella dysentery. Compound 2 was not active against all tested microorganisms at 200 microg/ml, which was the highest concentration tested. At this concentration, all four compounds were not active against Shigella sonnei. Cytotoxicity of ethanol crude extracts and isolated compounds from Spirostachys africana was determined using the sodium-2,3-bis-[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) assay on Vero cells. Compounds 2 and 3, isolated from Spirostachys africana, had up to three times higher [50% inhibitory concentration (IC(50) values; 300.9 and 308.9 microg/ml)] than the ethanol crude extracts (102.8 microg/ml) suggesting higher toxicity of the crude extract as compared to these two compounds. In contrast, compounds 1 and 4 were not cytotoxic to Vero cell lines (African green monkey) in vitro at the concentrations tested (IC(50)>400 microg/ml). This is the first report on the antibacterial activity and cytotoxicity of purified compounds from Spirostachys africana.     

Antileishmanial, antiplasmodial and cytotoxic activities of 12,16-dideoxy aegyptinone B from Zhumeria majdae Rech.f. & Wendelbo

The ethanol extract of Zhumeria majdae showed potent antileishmanial and antiplasmodial activity in vitro. Bioactivity guided fractionation of the extract led to the isolation of 12,16-dideoxy aegyptinone B. This compound exhibited potent in vitro antileishmanial activity with an IC(50) of 0.75 microg/mL and a strong antiplasmodial activity with IC(50) values of 1.3 and 1.4 microg/mL against chloroquine sensitive and resistant strains, respectively. This compound was further found to have mild cytotoxicity towards cancer cell lines.