Antimalarial activity in vitro of Cochlospermum tinctorium tubercle extracts

Antiplasmodial, antimalarial activities and toxicity of African medicinal plants: a systematic review of literature

BACKGROUND

Malaria still constitutes a major public health menace, especially in tropical and subtropical countries. Close to half a million people mainly children in Africa, die every year from the disease. With the rising resistance to frontline drugs (artemisinin-based combinations), there is a need to accelerate the discovery and development of newer anti-malarial drugs. A systematic review was conducted to identify the African medicinal plants with significant antiplasmodial and/or anti-malarial activity, toxicity, as wells as assessing the variation in their activity between study designs (in vitro and in vivo).

METHODS

Key health-related databases including Google Scholar, PubMed, PubMed Central, and Science Direct were searched for relevant literature on the antiplasmodial and anti-malarial activities of African medicinal plants.

RESULTS

In total, 200 research articles were identified, a majority of which were studies conducted in Nigeria. The selected research articles constituted 722 independent experiments evaluating 502 plant species. Of the 722 studies, 81.9%, 12.4%, and 5.5% were in vitro, in vivo, and combined in vitro and in vivo, respectively. The most frequently investigated plant species were Azadirachta indica, Zanthoxylum chalybeum, Picrilima nitida, and Nauclea latifolia meanwhile Fabaceae, Euphorbiaceae, Annonaceae, Rubiaceae, Rutaceae, Meliaceae, and Lamiaceae were the most frequently investigated plant families. Overall, 248 (34.3%), 241 (33.4%), and 233 (32.3%) of the studies reported very good, good, and moderate activity, respectively. Alchornea cordifolia, Flueggea virosa, Cryptolepis sanguinolenta, Zanthoxylum chalybeum, and Maytenus senegalensis gave consistently very good activity across the different studies. In all, only 31 (4.3%) of studies involved pure compounds and these had significantly (p = 0.044) higher antiplasmodial activity relative to crude extracts. Out of the 198 plant species tested for toxicity, 52 (26.3%) demonstrated some degree of toxicity, with toxicity most frequently reported with Azadirachta indica and Vernonia amygdalina. These species were equally the most frequently inactive plants reported. The leaves were the most frequently reported toxic part of plants used. Furthermore, toxicity was observed to decrease with increasing antiplasmodial activity.

CONCLUSIONS

Although there are many indigenous plants with considerable antiplasmodial and anti-malarial activity, the progress in the development of new anti-malarial drugs from African medicinal plants is still slothful, with only one clinical trial with Cochlospermum planchonii (Bixaceae) conducted to date. There is, therefore, the need to scale up anti-malarial drug discovery in the African region.

Comparing Medicinal Uses of Cochlospermaceae throughout Its Geographic Range with Insights from Molecular Phylogenetics

Species of the Cochlospermaceae, a small mostly pantropical plant family, were evaluated at a continental scale for medicinal uses in traditional medicine. This ethnobotanical information was placed in a phylogenetic framework to make informed predictions in the search for new medicines and bioactive compounds. Medicinal plant-use data were mapped onto a molecular phylogeny based on DNA sequences of nuclear and chloroplast markers. Associations of medicinal uses among closely related species occurring in different geographic regions and among diverse cultures were evaluated. The most common medicinal uses for these species are those used to treat skin ailments, gastro-intestinal problems, malaria, and liver issues. The plant species with the most numerous uses is Cochlospermum tinctorium, which occurs primarily in West Africa. Closely related species being used by cultural groups in different geographic regions to treat the same illnesses suggests the presence of bioactive compounds with potential biomedical value, since they may represent independent discoveries of similar medicinally-active compounds. This leads to the speculation that those closely related species not currently being used to treat these ailments may also contain identical or similar medicinally-active compounds and are worthy of laboratory investigations.

Medicinal Plants Used in Mali for the Treatment of Malaria and Liver Diseases

Today, ethno-pharmacology is a very important resource in order to discover new therapies for the current diseases. Moreover, another good justification for the ethno-pharmacological approach is to obtain new, effective, less expensive and simple therapies, limiting at the same time the cost of pharmaceutical research. Two major anti-malarial drugs widely used today, i.e. quinine and artemisinin, came respectively from Peruvian and Chinese ancestral treatments reported in the traditional medicines. In this contest, there is an urgent need for the discovery of new drugs, due to the critical epidemiological situation of this disease and to the growth of resistances. In Mali, malaria and liver diseases remain one of the leading public health problems. Many medicinal plants are often used, in local traditional medicine, for the treatment at the same time of malaria and liver diseases, including hepatic syndromes, jaundice, hepatitis and other hepatic disorders. Moreover, in the local language Bamanan, the word “ Sumaya” is used both for malaria and some liver diseases. In addition, we noted that some of the improved traditional phytomedicines produced by the Department of Traditional Medicine are prescribed by modern doctors both for malaria and liver diseases. In this review, pharmacological, toxicological and phytochemical data on Argemone mexicana L. (Papaveraceae), Cochlospermum tinctorium Perr. ex A. Rich (Cochlospermaceae), Combretum micranthum G.Don (Combretaceae), Entada africana Guillet Perr. (Mimosaceae), Erythrina senegalensis A. DC (Fabaceae), Mitragyna inermis (Willd) Kuntze (Rubiaceae), Nauclea latifolia Smith syn. Sarcocephalus latifolius (Smith) Bruce (Rubiaceae), Securidaca longepedunculata Fresen (Polygalaceae), Trichilia emetica Vahl. (Meliaceae), and Vernonia colorata (Willd) Drake (Asteraceae) are reported. Some of the collected data could be used to improve the actual herbal drugs and to propose new phytomedicines for the management of malaria and liver diseases.

Antiplasmodial activity of some phenolic compounds from Cameroonians Allanblackia

BACKGROUND

Plasmodium falciparum, one of the causative agents of malaria, has high adaptability through mutation and is resistant to many types of anti-malarial drugs. This study presents an in vitro assessment of the antiplasmodial activity of some phenolic compounds isolated from plants of the genus Allanblackia.

METHODS

Tests were performed on well plates filled with a fixed parasitized erythrocytes volume. Compounds to be tested were then added in wells. After incubation, tritiated hypoxanthine is added and the plates were returned to the incubator. After thawing, the nucleic acids are collected. Inhibitory Concentration 50 (IC50) was determined by linear interpolation.

RESULTS

From Allanblackia floribunda, have been isolated and characterized 1,7-dihydroxyxanthone 1, macluraxanthone 4, morelloflavone 9, Volkensiflavone 10 and morelloflavone 7-O-glucoside 11; from Allanblackia monticola, α-mangosine 2, rubraxanthone 3, allaxanthone C 5, norcowanine 6, tovophiline A 7, allaxanthone B 8 and from Allanblackia gabonensis, 1,7-dihydroxyxanthone 1. Six of them were evaluated for their antimalarial properties. The most active compound, macluraxanthone, presented a very interesting activity, with an IC50 of 0.36 and 0.27 µg/mL with the F32 and FcM29 strains respectively.

CONCLUSION

This work confirms that species of Allanblackia genus are medicinally important plants containing many biologically active compounds that can be used effectively as antiplasmodial.

Antimalarial and vasorelaxant constituents of the leaves ofAllanblackia monticola(Guttiferae)

Phytochemical investigation of the leaves of Allanblackia monticola led to the isolation and characterisation of five prenylated xanthones [1,6-dihydroxy-3,7-dimethoxy-2-(3-methylbut-2-enyl)xanthone 1, alpha-mangostin 2, tovophyllin A 3, allanxanthone C 4 and 1,7-dihydroxy-3-methoxy-2-(3-methylbut-2-enyl)xanthone 5], two biflavonoid derivatives (amentoflavone 6 and podocarpusflavone A 7) and one pentacyclic triterpene (friedelan-3-one 8). The structures of these compounds were established on the basis of homo- and hetero-nuclear, one- and two-dimensional, nuclear magnetic resonance. Compounds 2-8 and a crude methanolic extract of A. monticola leaves were each tested for antimalarial activity in vitro, using the chloroquine-sensitive F32 and chloroquine-resistant FcM29 strains of Plasmodium falciparum; the median inhibitory concentrations (IC(50)) recorded varied from 0.7 to 83.5 mug/ml. The cytotoxicities of the compounds and crude extract, against cultures of human melanoma cells (A375), were then investigated, and cytotoxicity/antimalarial IC(50) ratios of 0.6-16.75 were recorded. In tests involving aortic rings from guinea pigs, a crude extract of the leaves of A. monticola was found to induce concentration-dependent vasorelaxation, causing up to 82% and 42% inhibition of noradrenaline- and KCl-induced contractions, respectively. The corresponding values for compounds 2 and 6 when tested against noradrenaline-induced contractions were approximately 18% and 35%, respectively.

Macrocyclic spermidine alkaloids from Androya decaryi L. Perrier

Three new spermidine alkaloids and two known compounds were isolated from the leaves of Androya decaryi. Their structures were elucidated on the basis of their spectroscopic data (NMR and mass spectrometry), by X-Ray diffraction and by comparison with literature values. Evaluation of the in vitro antiplamosdial properties of the isolated compounds revealed they did not possess any significant activity.

Aqueous Methanol Extracts of Cochlospermum tinctorium (A. Rich) Possess Analgesic and Anti-inflammatory Activities

Cochlopermum tinctorium A. Rich. (Cochlospermaceae) is a commonly used medicinal plant in the West Africa sub-region for the management of various conditions including pain and inflammatory conditions. In the present study, we report the analgesic and anti-inflammatory activities of the aqueous methanol leaf (20-80 mg/kg), root (7.5-30 mg/kg), and root bark (20-80 mg/kg) extracts of the plant. The analgesic potentials of the extracts were studied using acetic acid induced writhing and hot plate tests in mice while the anti-inflammatory activity was investigated using carrageenan-induced paw edema in rats.The extracts significantly and dose dependently inhibited the acetic acid-induced writhing in mice. However, the highest protection against writhing was produced by aqueous methanol leaf extract at the dose of 80 mg/kg (96.65%) which even was greater than that of the standard agent, ketoprofen (82.30%). The extracts did not significantly increase mean latency of response in the hot plate test. However, aqueous methanol root bark extract at the dose of 20 mg/kg significantly (P < 0.05) increased the mean latency of pain response. While the extracts of the root and root bark extracts of the plant afforded non dose-dependent protection against carrageenan-induced edema, the aqueous methanol leaf extract significantly and dose-dependently inhibited carrageenan-induced hind paw edema at the end of the third hour.The present study suggests that the aqueous methanol leaf, root, and root bark extracts of Cochlopermum tinctorium possess analgesic and anti-inflammatory activities which lend some credence to the ethnomedical claim of the use of the plant in the management of pain and inflammatory conditions.

Plants used by native Amazonian groups from the Nanay River (Peru) for the treatment of malaria

AIM OF THE STUDY

In order to evaluate the antimalarial potential of traditional remedies used in Peru, Indigenous and Mestizo populations from the river Nanay in Loreto were interviewed about traditional medication for the treatment of malaria.

MATERIALS AND METHODS

The survey took place on six villages and led to the collection of 59 plants. 35 hydro-alcoholic extractions were performed on the 21 most cited plants. The extracts were then tested for antiplasmodial activity in vitro on Plasmodium falciparum chloroquine resistant strain (FCR-3), and ferriprotoporphyrin inhibition test was also performed in order to assume pharmacological properties.

RESULTS

Extracts from 9 plants on twenty-one tested (Abuta rufescens, Ayapana lanceolata, Capsiandra angustifolia, Citrus limon, Citrus paradise, Minquartia guianensis, Potalia resinífera, Scoparia dulcis, and Physalis angulata) displayed an interesting antiplasmodial activity (IC(50)<10 μg/ml) and 16 remedies were active on the ferriprotoporphyrin inhibition test.

CONCLUSIONS

The results give scientific validation to the traditional medical knowledge of the Amerindian and Mestizo populations from Loreto and exhibit a source of potentially active plants.

An antiplasmodial new (bis)indole alkaloid from the hard coral Tubastraea sp

Tubastarea sp., a stony coral (Dendrophylliidae) from the Great Hanish in the Archipelago of the Hanish Islands, Yemen, contains, in addition to the known aplysinopsin (1) and 6-bromo-3'-deimino-3'-oxoaplysinopsin (2), the new bis(indole) alkaloid (3). The structures of compounds (1-3) were elucidated by interpretation of spectral data. Compound 3 inhibits the growth of Plasmodium falciparum (chloroquine-resistant strain) with an IC(50) 1.2 microg mL(-1).

Four anti-protozoal and anti-bacterial compounds from Tapirira guianensis

Tapirira guianensis is a common tree used in traditional medicine in French Guiana against several infectious diseases (malaria, leishmaniasis, bacteria, etc.). The bioassay-guided purification of CH(2)Cl(2) bark extract led to the isolation of four cyclic alkyl polyol derivatives: 4,6,2'-trihydroxy-6-[10'(Z)-heptadecenyl]-1-cyclohexen-2-one (1a), 1,4,6-trihydroxy-1,2'-epoxy-6-[10'(Z)-heptadecenyl]-2-cyclohexene (1b), 1,4,5,2'-tetrahydroxy-1-[10'(Z)-heptadecenyl]-2-cyclohexene (2), and 1,3,4,6-tetrahydroxy-1,2'-epoxy-6-[10'(Z)-heptadecenyl]-cyclohexane (3). The structures were established on the basis of 1D and 2D NMR analyses. The anti-leishmanial, anti-plasmodial, anti-bacterial (on Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli), and anti-fungal (on Candida albicans) activities of the extracts and of these original compounds were evaluated. Two showed medicinal interest supporting the traditional uses of the plant. The structures were established through spectral analyses of the isolates and their derivatives.

Electrochemical impedance spectroscopy to study physiological changes affecting the red blood cell after invasion by malaria parasites

The malaria parasite, Plasmodium falciparum, invades human erythrocytes and induces dramatic changes in the host cell. The idea of this work was to use RBC modified electrode to perform electrochemical impedance spectroscopy (EIS) with the aim of monitoring physiological changes affecting the erythrocyte after invasion by the malaria parasite. Impedance cell-based devices are potentially useful to give insight into cellular behavior and to detect morphological changes. The modelling of impedance plots (Nyquist diagram) in equivalent circuit taking into account the presence of the cellular layer, allowed us pointing out specific events associated with the development of the parasite such as (i) strong changes in the host cell cytoplasm illustrated by changes in the film capacity, (ii) perturbation of the ionic composition of the host cell illustrated by changes in the film resistance, (iii) releasing of reducer (lactic acid or heme) and an enhanced oxygen consumption characterized by changes in the charge transfer resistance and in the Warburg coefficient characteristic of the redox species diffusion. These results show that the RBC-based device may help to analyze strategic events in the malaria parasite development constituting a new tool in antimalarial research.

Alisiaquinones and alisiaquinol, dual inhibitors of Plasmodium falciparum enzyme targets from a New Caledonian deep water sponge

Four new meroterpenes, alisiaquinones A-C (1-3) and alisiaquinol (4), were isolated from a New Caledonian deep water sponge. Their structures and relative stereochemistry were elucidated by spectroscopic data analysis. They are related to xestoquinone, but showed unusual substitution on a tetrahydrofuran junction. They displayed micromolar range activity on two enzymatic targets of importance for the control of malaria, the plasmodial kinase Pfnek-1 and a protein farnesyl transferase, as well as on different chloroquine-sensitive and -resistant strains of Plasmodium falciparum. Alisiaquinone C displayed a submicromolar activity on P. falciparum and a competitive selectivity index on the different plasmodial strains.

Are West African plants a source of future antimalarial drugs?

Ethnopharmacology is a very interesting resource in which new therapies may be discovered. In the case of malaria, two major antimalarial drugs widely used today came originally from indigenous medical systems, that is quinine and artemisinin, from Peruvian and Chinese ancestral treatments, respectively. There is an urgent need for the discovery of new drugs due to the critical epidemiological situation of this disease. New inexpensive therapies that are simple to use and that will limit the cost of drug research are good justifications for this ethnopharmacological approach. Therefore, the aim of this review is to empirically analyse plants that are used for antimalarial treatment in West Africa, and to determine those with real promising antimalarial activity. The major leads such as those extracted from Cochlospermum, Cryptolepsis, Guiera and Azadirachta have been highlighted. Indeed, some extracts seem to be promising in future research, but development of new isolation and characterization techniques, for designing new derivatives with improved properties need to be discussed.

Amazonian plants from Peru used by Quechua and Mestizo to treat malaria with evaluation of their activity

Indigenous Quechua and Mestizo populations from distinct areas in Loreto, Peru, were interviewed about traditional medication for the treatment of malaria. An ethnographic survey concerning the native theory of illness aetiology in the specific case of malaria permitted the elaboration of an efficient ethnopharmacological enquiry. The survey took place on three main zones corresponding to villages on the Napo and the Pastaza rivers (for the Quechua), and in the surroundings of Iquitos (for the Mestizos) and led to the collection of 14 plants. Serial extractions in hexane, dichloromethane, and methanol were performed on the different parts of the plants collected. The extracts were then tested for antiplasmodial activity in vitro. Seven plants displayed antiplasmodial activity (IC(50) from 2 to 25 microg/mL) and usually low cytotoxicity, indicating their antiplasmodial specificity. The results give scientific validation to the traditional medical knowledge of Quechua and Mestizo populations from Loreto and confirm a source of potentially active plants.

Antimalarial activity from three ascidians: an exploration of different marine invertebrate phyla

Recent research suggests that marine organisms may produce compounds with activity against malaria parasites. Of a total of 27 aqueous extracts from different marine species, collected on the northwest Cuban coast, 20 were considered as showing no significant activity against Plasmodium falciparum F32, with minimum inhibitory concentrations (MIC) >500 microg/ml, while seven extracts (MIC < or =500 microg/ml) were selected for further investigation by determining their selectivity indices and in vivo antimalarial activity. Three species of tunicates were chosen, as more than 50% reduction of P. berghei parasitaemia was produced after administration of 250 or 500 mg/kg of their crude extracts into infected mice. The aqueous extracts of Microcosmus goanus, Ascidia sydneiensis and Phallusia nigra were partitioned between water and n-butanol; the organic phases inhibited P. falciparum growth by 50% at concentrations of 17.5 microg/ml, 20.9 microg/ml and 29.4 microg/ml respectively. In general, these results are similar to those of most ethnobotanical surveys. Further chemical studies are being undertaken in order to isolate new antimalarial compounds from these Caribbean tunicates.

Antiplasmodial activity and cytotoxicity of plants used in West African traditional medicine for the treatment of malaria

Eighteen plants originating from Ivory Coast were selected by ethnobotanical survey as plants commonly used by traditional healers for the treatment of malaria. Extracts of these plants were tested on two strains of Plasmodium falciparum: FcM29-Cameroon (chloroquine-resistant strain) and a Nigerian chloroquine-sensitive strain. The powdered plants were used to prepare three kinds of extracts: by decoction in water, in ethanol (95%) and in pentane. A radioactive micromethod allowed the evaluation of the antiplasmodial in vitro activity of the extracts on P. falciparum. Concentrations inhibiting 50% of the parasite growth (IC50) ranged from 18 microg/ml to more than 500 microg/ml for aqueous and ethanol extracts and from 4.3 microg/ml to more than 500 microg/ml for pentane extracts. Cytotoxicity was estimated on A375 melanoma cells and a cytotoxicity/antiplasmodial index (CAR) was calculated for each extract, ranging from 1 to 10. The pentane extracts of Cola caricaefolia and Uvaria afzelii, which revealed the strongest antiplasmodial activity had CAR values of about 10.

InVitro and inVivo Antimalarial Activity of Derivatives of 1,10-Phenanthroline Framework

A series of trisubstituted 1,10-phenanthrolines was prepared. These compounds exhibited mild to high biological activities in vitro both toward chloroquino-resistant FcB1-Columbia and FcM29-Cameron strains and Nigerian chloroquino-sensitive strain of Plasmodium falciparum. Cytotoxicity of the most active compounds was estimated showing that one compound (10) exhibited a selective activity against malaria parasite (selectivity indexes of 52 and 144). Antiplasmodial activity of this derivative was optimized by N-10 alkylation and the phenanthrolinium salt (15) submitted to an in vivo study using mice infected by P. vinckei petteri showing an ED50 of 7.86 mg/kg/day.

Prenylated Xanthone Derivatives with Antiplasmodial Activity from Allanblackia monticola STANER L.C

Further study of the methanol extract of the stem bark of Allanblackia monticola STANER L.C. resulted in the isolation of a new prenylated xanthenedione, designated allanxanthone C, together with the five known xanthones, garciniafuran, tovophyllin A, rubraxanthone, norcowanin and mangostin and one saponin, stigmasterol-3-O-beta-D-glucopyranoside. The structure of the new compound was established by detailed spectroscopic analysis to be 1,2-dihydro-3,6,8-trihydroxy-1,1,7-tri(3-methylbut-2-enyl)xanthen-2,9-dione (3-hydroxyapetalinone C). The methanol extract and pure compounds were tested on two strains of Plasmodium falciparum, F32 (chloroquine sensitive) and FcM29 (chloroquine resistant). The IC50 values obtained ranged from 0.6 to 8.9 microg/ml. Their cytotoxicity was estimated on human melanoma cells (A375) and the cytotoxicity/antiplasmodial ratio was found to be between 15.45 and 30.46. The antimicrobial activities against a range of microorganisms of the crude extract and some of these compounds are also reported.

New clerodane diterpenoids from Laetia procera (Poepp.) Eichler (Flacourtiaceae), with antiplasmodial and antileishmanial activities

Extracts of Laetia procera (Flacourtiaceae) displayed significant in vitro activity against Plasmodium falciparum. P. falciparum bioassay guided fractionation of a trunk bark extract of this plant led to the isolation of six clerodane diterpenoids (1-6) and a butanolide (7). Five of these compounds are new and called Laetiaprocerine A-D (3-6) and Laetianolide A (7). Their structures were established on the basis of 1D and 2D NMR experiments. Absolute configurations of 1 and 2 were determined by a modified Mosher's method and the absolute configuration of 5 by chemical correlation. The clerodane diterpenoids displayed activities against P. falciparum with an IC50 down to 0.5 microM on FCb1 and F32 strains, and also cytotoxicity toward human tumor cell line MCF7. The most active compound showed a selectivity index of 6.8. Some of these compounds also displayed activities against Leishmania amazonensis amastigote axenic stages and promastigote.

Medicinal use of Cochlospermum tinctorium in Mali Anti-ulcer-, radical scavenging- and immunomodulating activities of polymers in the aqueous extract of the roots

Cochlospermum tinctorium A. Rich. (Cochlospermaceae) is a widely used medicinal plant in the West African country, Mali. An ethnopharmacological survey was conducted and 106 traditional practitioners interviewed. The roots were the part of the plant reported to be the most frequently used for medicinal purposes. The main indications were to treat jaundice (41), gastro intestinal diseases or ailments (28), malaria (12), schistosomiasis (10) and dysurea (6). A high-molecular weight water extract (25, 50 and 100 mg/kg, body weight) significantly inhibited HCl/ethanol-induced gastric lesions in mice. The extract showed DPPH-radical scavenging- and immunomodulating activities in vitro. The main components of the extract were identified as polysaccharides (59.3%) and polyphenols (9.3%). The polysaccharides were purified and characterised as highly complex pectic arabinogalactans type II. As parts of the polyphenol compounds gallotannins and ferulic acids were identified. This study shows that the polysaccharides are partly responsible for the bioactivities observed in vitro. Both polysaccharides and polyphenols may be responsible for the anti-ulcer activities observed.

Studies on medicinal plants of Ivory Coast: investigation of Sida acuta for in vitro antiplasmodial activities and identification of an active constituent

Sida acuta Burm. (Malvaceae) originating from Ivory Coast was selected after an ethnobotanical survey: traditional healers of malaria commonly used this plant for the treatment. Extracts were tested on two strains of Plasmodium falciparum: FcM29-Cameroon (chloroquine-resistant strain) and a Nigerian chloroquine-sensitive strain. Extracts were obtained by preparing decoction in water of the powdered plant, the technique used by most of the traditional healers. An ethanol extract was then made and tested. The IC50 values obtained for these extracts ranged from 3.9 to -5.4 microg/ml. Purification of this active fraction led to the identification of cryptolepine as the active antiplasmodial constituent of the plant.

N'Dribala (Cochlospermum planchonii) versus chloroquine for treatment of uncomplicated Plasmodium falciparum malaria

The aim of this work was to assess the efficacy of oral N'Dribala (tuberous roots decoction of Cochlospermum planchonii Hook) treatment versus chloroquine in non-severe malaria. The study included 85 patients with uncomplicated Plasmodium falciparum infection in Banfora, Burkina Faso. Forty-six patients that received N'Dribala beverage were compared to 21 patients treated with chloroquine. All patients were monitored with clinical examination and a parasitemia control by Giemsa-stained thick films. N'Dribala appeared safe and statistically as efficient as chloroquine for the treatment of uncomplicated Plasmodium falciparum malaria. At day 5 (D5), 57% of chloroquine-treated and 52% of N'Dribala-treated patients were cured with no detectable parasitemia (parasite density (Pd): 0) and more than 90% of whole patients were asymptomatic. N'Dribala is easily available in this country, cheap, without significant side effects and efficient with a clearly demonstrated activity on Plasmodium falciparum blood stages. This study enhances the traditional use of the Cochlospermum planchonii as alternative therapy for treatment of non-severe malaria.

In vitro antiplasmodial activity and cytotoxicity of ethnobotanically selected Ivorian plants

Eight extracts from four Ivorian medicinal plants, traditionally used to treat malaria, were tested for their antiplasmodial activity in vitro by assessing their ability to inhibit the uptake of [3H]hypoxanthine into the Plasmodium falciparum K1 chloroquine-resistant strain. The most active extract was the methylene chloride extract of Anogeissus leiocarpus which exhibited an IC(50) value of 3.8 micro g/ml. Inhibition of the growth of Plasmodium falciparum was also observed with the methylene chloride extract of Cochlospermum planchonii and Microdesmis keayana as well as with both methylene chloride and methanolic extracts of Hymenocardia acida.

Antiplasmodial compounds from Cochlospermum tinctorium

Fractionation of an ethanol extract of roots of Cochlospermum tinctorium afforded five compounds: 3-O-E-p-coumaroylalphitolic acid (1), cochloxanthin (2), dihydrocochloxanthin (3), alphitolic acid (4), and 1-hydroxytetradecan-3-one (5). This is the first example of a 1-hydroxyalkan-3-one obtained from plant material after gentle workup. The antiplasmodial activities of the compounds were determined, and the IC(50) value of 3-O-E-p-coumaroylalphitolic acid was 2.3 microM.

Ethnopharmacology of the Popoluca, Mexico: an evaluation

Medicinal plants are an essential part of indigenous pharmaceutical systems. We studied the medicinal plants used by the Popoluca of the Sierra Santa Marta (Eastern Mexico). This study is part of a series on the ethnopharmacology of various Macro-Mayan groups. During 16 months of ethnobotanical fieldwork, 614 taxa used medicinally and 4488 individual use-reports were documented. The data are analysed using the concept of the "healers' consensus" in order to identify culturally important medicinal plants. The medicinal uses of the plants were grouped into 13 illness categories. The responses for each species were summarized for each of the categories and were ordered by frequency of mention. The most frequently recorded medicinal plants of the Popoluca are Hamelia patens, used to stop bleeding from wounds, and Byrsonima crassifolia, used against diarrhoea. The high-ranked medicinal species were assessed pharmacognostically using published phytochemical and pharmacological data. Popoluca medicinal uses were fairly consistent with published data on active ingredients for those plants for which such data exist. However, data is still lacking for many other species. Toxicological studies are particularly scarce. This study will be used as a basis for subsequent studies on the pharmacology and phytochemistry of medicinal plant species.

A search for natural bioactive compounds in Bolivia through a multidisciplinary approach. Part V. Evaluation of the antimalarial activity of plants used by the Tacana Indians

One hundred and twenty-five extracts of 122 different plant species traditionally used by the Tacana, a native community living in lowland forest at the base of the last foothills of the Cordillera Oriental of the Bolivian Andes, were screened for antimalarial activity in vitro on Plasmodium falciparum chloroquine resistant (D2) and sensitive strains (F32), and were evaluated in vivo on rodent malaria Plasmodium berghei. Five ethanolic stembark extracts showed marked activity either in vitro or in vivo, and only one of them, Bowdichia virgilioides being traditionally used against malaria, was active in vitro (IC50=1 microg/ml on both strains) and in vivo (51% at 100 mg/kg). Other active extracts were from Caesalpinia pluviosa bark displaying activity in vitro against chloroquine resistant strain (IC50 8.3 microg/ml), traditionally used against dysentery; two Lauraceae bark extracts, Nectandra aff. hihua and Licaria canella respectively used for construction purposes and against stomach ache, both displaying activity in vitro against P. falciparum sensible and resistant strains (IC50 around 4 microg/ml); finally, the bark of a strongly aromatic Burseraceae, Protium glabrescens exuding an anti-inflammatory and analgesic resin, was active in vivo only (61% at 100 mg/kg). Results are discussed in relation with Tacana traditional medicine.

Antiplasmodial activity of plant extracts used in west African traditional medicine

Five plants originating from Ivory Coast were selected after an ethnobotanical survey, Alchornea cordifolia, Mitragyna inermis, Nauclea diderrichii, Pterocarpus santalinoides, and Terminalia glaucescens. Traditional healers for the treatment of malaria commonly used these plants. Extracts of these plants were tested on three strains of Plasmodium falciparum, FcB1-Colombia and FcM29-Cameroon (chloroquine-resistant strains) and a Nigerian chloroquine-sensitive strain. Extracts were obtained by preparing decoction in water of the powdered plant, the technique used by most of the traditional healers. A radioactive micromethod allowed the evaluation of the in vitro activity of the extracts on P. falciparum. Concentrations inhibiting 50% of the parasite growth (IC(50)) ranged from 2.34 to more than 500 microg/ml according to the plant. For the most active plants (A. cordifolia and T. glaucescens) ethanol and pentane extracts were made and tested. The IC(50) values obtained for these extracts ranged from 0.35 to 43.40 microg/ml. The stage specificity of the ethanol extracts of A. cordifolia and T. glaucescens and pentane extract of T. glaucescens on the parasite erythrocytic cycle were determined. The ethanol extract of T. glaucescens showed its highest activity at the transition from the trophozoite to the schizont stages. Cytotoxicity was estimated on human fibroblasts (HeLa) cells and a cytotoxicity/antiplasmodial index was calculated, it ranged between 5 and 21, and the best antiplasmodial extract (T. glaucescens ethanol extract) had the higher index (>20).

In vitro antiplasmodial activity of stem and root extracts of Nauclea latifolia S.M. (Rubiaceae)

Aqueous extracts from Nauclea latifolia S.M. (Rubiaceae), a plant commonly used in Ivory Coast by traditional healers for the treatment of malaria, were tested on two strains of Plasmodium faliparum: FcB1-Colombia (chloroquine-resistant) and a Nigerian strain (chloroquine-sensitive). The extracts were obtained from stems and roots of the plant in two forms, infusion and decoction, both methods used by most traditional healers. The in vitro activity of N. latifolia extracts on P. falciparum was assessed both visually and by a radioactive method. The visual analysis allowed determination of the time of extract action on the erythrocytic cycle, as well as the parasitic stage of most inhibitory effect. Similar results were obtained applying fresh, frozen or lyophilized extracts. The IC50 values determined were within the range already reported for other antimalarial plants such as Azadirachta indica A. Juss (Meliaceae) or Artemisia annua L. (Asteraceae). Aqueous extracts of N. latifolia inhibited P. falciparum (FcB1 strain) mainly at the end of the erythrocytic cycle (32nd to 48th hour).

In vitro antimalarial activity of penduline, a bisbenzylisoquinoline from Isopyrum thalictroides

Two bisbenzylisoquinolines, tetrandrine and penduline, were purified from Isopyrum thalictroides. When tested for antimalarial activity in vitro, penduline was efficient at concentrations fivefold lower than those of tetrandrine. In highly synchronized parasite cultures, penduline mostly interfered between the 8th and the 32nd hours of the parasite cycle.

Continuous culture of Plasmodium falciparum: its impact on malaria research

The methods developed by us in 1976 for the continuous culture of the erythrocytic stages of Plasmodium falciparum make this organism available to a large variety of scientists. As a result, much has been learned about P. falciparum during the past 20 years. Here we attempt to emphasize recent developments in the diverse aspects for which the culture method has been particularly useful: chemotherapy; drug resistance; vaccine development; pathogenesis; export of proteins into the host cell; cell biology, the mitochondrion and the plastid; innate resistance involving mutant human erythrocytes; gametocytogenesis; genetics, transfection; molecular biology; biochemistry; extracellular cultivation.

In vivo and in vitro antiplasmodial activities of some plants traditionally used in Guatemala against malaria

We present an evaluation of the antiplasmodial and cytotoxic effects of four plants commonly used in Guatemalan folk medicine against malaria. Methanol extracts of Simarouba glauca D. C., Sansevieria guineensis Willd, Croton guatemalensis Lotsy, and Neurolaena lobata (L.)R.Br. significantly reduced parasitemias in Plasmodium berghei-infected mice. Dichloromethane fractions were screened for their cytotoxicities on Artemia salina (brine shrimp) larvae, and 50% inhibitory concentrations were determined for Plasmodium falciparum in in vitro cultures. Both chloroquine-susceptible and -resistant strains of P. falciparum were significantly inhibited by these extracts. Of all dichloromethane extracts, only the S. glauca cortex extract was considered to be toxic to nauplii of A. salina in the brine shrimp test.

Composition and antimalarial activity in vitro of volatile components of Lippia multiflora

The essential oil of Lippia multiflora was prepared by hydrodistillation of leaves and stalks and characterized by GC and mass spectroscopy. The oil was tested for antimalarial activity on in vitro cultures of Plasmodium falciparum (FcB1-Columbia chloroquine-resistant strain and F32-Tanzania chloroquine-sensitive strain). The dilutions inhibiting the in vitro growth of the parasite by 50% 24 and 72 hr after administration of the essential oil to the parasite culture were 1/12,000 and 1/21,000, respectively. When tested on a highly synchronized culture, the essential oil inhibited growth mostly at the trophozoite-schizont step, indicating a potential effect on the first nuclear division of the parasite.