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S L Lumpu,
C M Kikueta,
M E Tshodi,
A P Mbenza,
O K Kambu,
B M Mbamu,
P Cos,
L Maes,
S Apers, L Pieters,
R K Cimanga
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ABSTRACT: ETHNOPHARMACOLOGICAL RELEVANCE: To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases. MATERIALS AND METHODS: The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resitant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well. RESULTS: The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of P. falciparum with IC50 values ranging from 2 to 5µg/ml, and good activity against T. b. brucei and T. cruzi with IC50 values ranging between 5 and 10µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC50 values <10µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC50>64µg/ml). In general, the aqueous extracts (traditional decoctions) showed the highest selectivity, especially against P. falciparum. CONCLUSION: These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.
Journal of ethnopharmacology 04/2013; · 2.32 Impact Factor
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ABSTRACT: To evaluate the antidiarrhoeal properties of Alstonia congensis leaves claimed to be effective for the treatment of diarrhoea by traditional healers during our ethnopharmacological investigation conducted in Kinshasa, Democratic Republic of Congo.
The aqueous extract (decoction), and the 80% hot methanol extract (Soxhlet extraction) were obtained. This last extract was fractionated. The antidiarrhoeal activity was evaluated using castor oil and magnesium sulphate-induced diarrhoea in animals. The potential antibacterial activity of all samples was also assessed in vitro.
At all oral doses of 100 and 200 mg/kg body weight, all A. congensis samples showed significant and dose-dependent antidiarrhoeal activity in treated Wistar rats characterised by significant increase of onset time and decrease of all other diarrhoeal parameters at various degrees compared to untreated groups in both models. At the highest oral dose of 200 mg/kg bodyweight, the 80% hot methanol and aqueous extracts produced 79.8 ± 2.1% and 78.6 ± 0.5%, and 75.0 ± 2.1% and 71.4 ± 2.1% inhibition of defecation and diarrhoea respectively against castor oil-induced diarrhoea, and 75.0 ± 1.2% and 73.3±1.2% inhibition of diarrhoea respectively against magnesium sulphate-induced diarrhoea. The 80% hot methanol and aqueous detannified extracts showed low activity (42-47% inhibition of defecation and/or diarrhoea in both tests) suggesting that tannins may be responsible for the observed activity. At the same oral doses, the total alkaloid extract, the chloroform soluble fraction rich in alkaloids, the 80% methanol and the alkaline aqueous soluble subfractions produced more than 50% inhibition of defecation and/or diarrhoea in both tests. From the antibacterial testing in vitro, results indicated that all A. congensis samples exhibited an antibacterial activity mainly against bacteria implicated in diarrhoea with MIC and MBC values in the range of 15.6-500 μg/ml. The most active samples were the aqueous (decoction) and the 80% hot methanol dried extracts, the chloroform subfraction rich in alkaloids and the total alkaloid extract (MIC: 15.7-125 μg/ml, MBC: 31.2-250 μg/ml). Proteus varibilis was found to be the most resistant microorganism.
These reported results can partly support and justify the traditional use of extracts from Alstonia congensis leaves for the treatment of diarrhoea in tradittional medicine.
Journal of ethnopharmacology 05/2012; 142(3):620-6. · 2.32 Impact Factor
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D Musuyu Muganza,
B I Fruth,
J Nzunzu Lami,
G K Mesia,
O K Kambu,
G L Tona,
R Cimanga Kanyanga,
P Cos,
L Maes,
S Apers, L Pieters
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ABSTRACT: The antiprotozoal and cytotoxic activity of the aqueous extracts from 33 medicinal plants, used by traditional healers for the treatment of various parasitic diseases and collected after an ethnopharmacological inventory conducted in the Bolongo area, Bandundu province in DR Congo, was evaluated.
Decoctions were prepared, lyophilized and evaluated for in vitro antiprotozoal activity against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum, and the chloroquine- and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Cytotoxicity against MRC-5 cells was included to assess selectivity of activity.
Most of the tested extracts exhibited pronounced (IC(50)≤5μg/ml) or good (5<IC(50)≤10μg/ml) antiprotozoal activity against one or more of the selected protozoa. A total of 19 plant extracts inhibited Trypanosoma b. brucei, especially the extract from Isolona hexaloba stem bark (IC(50)=1.95μg/ml, SI=16.5); 8 plant extracts were active against Trypanosoma cruzi, the extracts from Enanatia chlorantha stem bark and Quassia africana root bark being the most active with IC(50) values of 1.87 and 1.88μg/ml, respectively (SI=3.0 and 3.3, respectively); 8 plant extracts showed activity against Leishmania infantum, with extracts from Napoleona vogelii stem bark and Quassia africana root bark as the most active with IC(50) values of 5.66 and 5.04μg/ml (SI=11.3 and 1.2). Finally, 9 plant extracts inhibited Plasmodium falciparum K1 with the extracts from Quassia africana (root bark and stem bark) being the most active ones with IC(50) values of 0.46 and 1.27μg/ml (SI=13.7 and 13.6). Extracts from Enantia chlorantha stem bark, Piptadeniastrum africanum stem bark and Quassia africana root bark were cytotoxic for MRC-5 cells (CC(50)<10μg/ml).
These results can partly support and justify the traditional use of some of these plant species for the treatment of parasitic diseases.
Journal of ethnopharmacology 03/2012; 141(1):301-8. · 2.32 Impact Factor
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ABSTRACT: This paper describes the construction of a QSAR model to relate the structures of various derivatives of neocryptolepine to their anti-malarial activities. QSAR classification models were build using Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Classification and Regression Trees (CART), Partial Least Squares-Discriminant Analysis (PLS-DA), Orthogonal Projections to Latent Structures-Discriminant Analysis (OPLS-DA), and Support Vector Machines for Classification (SVM-C), using four sets of molecular descriptors as explanatory variables. Prior to classification, the molecules were divided into a training and a test set using the duplex algorithm. The different classification models were compared regarding their predictive ability, simplicity, and interpretability. Both binary and multi-class classification models were constructed. For classification into three classes, CART and One-Against-One (OAO)-SVM-C were found to be the best predictive methods, while for classification into two classes, LDA, QDA and CART were.
Analytica chimica acta 10/2011; 705(1-2):98-110. · 4.31 Impact Factor
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ABSTRACT: Saponins are high molecular weight glycosides which are known for their broad range of biological activities. In case of Maesa lanceolata, a tree growing in African countries, the maesasaponins showed virucidal, haemolytic, molluscicidal and anti-angiogenic activity. Since the different activities are dependent on the structure of the saponins, a method was developed and validated for the analysis of the individual saponins in this plant. Since the saponins were only present in small amounts, it was necessary to develop a very sensitive analytical method. For the fast and sensitive analysis of the extracted and purified plant samples ultra-performance liquid chromatography was coupled to a triple quadrupole mass spectrometer for MS/MS detection. A method in positive ESI mode, using sodium acetate in the mobile phase, was developed. The sodium adduct ion was selected as the precursor ion since it provided better sensitivity and a better, more stable fragmentation compared to the deprotonated and protonated ions. The intensity of the signal obtained by fragmentation of the sodium adducts of the saponins, was optimized by the addition of different concentrations of sodium acetate to the mobile phase. Reference standards were not available for all 14 saponins. Therefore, a relative MS/UV response was calculated allowing the estimation of the saponins in real samples. alpha-Hederin was used as external standard. The method was linear over the investigated concentration range with a good correlation coefficient (>0.99). The intra- and inter-day precisions were below 15% for most maesasaponins with the exception of maesasaponin II, which showed a precision within 20%. The recoveries of the spiked pure compounds maesasaponin IV.1 and VII.1 were 96.6% and 85.5%, respectively. The validated method can be applied in the investigation of the content of 14 saponins in transgenic and non-transgenic plant material of M. lanceolata.
Talanta 06/2010; 81(4-5):1258-63. · 3.79 Impact Factor
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ABSTRACT: The most well known food-based strategies to modulate the composition of the intestinal microbiota are the dietary use of prebiotics, probiotics and their combination, synbiotics. Currently established prebiotic compounds are mainly targeting the bifidobacteria population of the colon microbiota. A good illustration of the importance of high colonic bifidobacteria levels is the observation that breast milk creates an environment in the colon (because of its high amount in galacto-oligosaccharides with prebiotic activity) favouring the development of a simple flora, dominated by bifidobacteria to which various health benefits have been ascribed. Currently, high colonic bifidobacteria levels has been considered favourably at all ages and strategies to augment their presence have been demonstrated in placebo-controlled intervention studies; e.g. in toddlers to reduce sickness events, in adults to reduce the risk for developing gastrointestinal diseases and in the elderly to re-enhance their declining immune activity. The intestinal microbiota can be considered as a metabolically adaptable and rapidly renewable organ of the body. However, unbalances in its microbial community and activities are found to be implicated in disease initiation and progression, such as chronic inflammatory bowel diseases and colonic cancers. Restoration of this balance by increasing bifidobacteria levels has demonstrated to reduce disease severity of patients and to improve well-being in healtly volunteers. New emerging evidence on the difference in the composition of the colonic microbiota between obese and lean volunteers has opened new areas for pre-, pro- and synbiotic research. Additionally, as knowledge will increase about the microbial bio-conversion of polyphenolic compounds into bioactive metabolites in the colon and whether food-based strategies can augment such bioconversion into more potent compounds with anti-oxidant and/or anti-inflammatory activity new areas of research will be discovered. This paper provides an up-to-date review of the health benefits associated to the induction of high bifidobacteria levels in the colon by the use of prebiotics (inulin and oligofructose). New areas of emerging science will be discussed as well.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2009; 60 Suppl 6:5-11. · 2.27 Impact Factor
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ABSTRACT: The study was aimed to evaluate the in vitro antispasmodic activity of Morinda morindoides leaves aqueous extract, its soluble fractions and isolated compounds to provide the pharmacological basis for its use for the treatment of constipation and diarrhoea in traditional medicine.
The antispasmodic activity of each sample was evaluated on acetylcholine (ACh) and the depolarized KCl solution induced contractions on guinea-pig isolated ileum suspended in Tyrode's solution.
At a test concentration of 40mug/ml in organ bath, the aqueous extract and its petroleum ether soluble fraction showed a spasmogenic effect on both agonists. The diethylether, ethyl acetate, n-butanol and residual aqueous phase soluble fractions from the partition of the aqueous extract exhibited spasmolytic activity producing 47-100% inhibition of contractions induced by both agonists with IC(50) values ranged from 6 to 15 microg/ml according to the case. In addition, the n-butanol and residual aqueous phase soluble fractions showed an inhibitory effect of 75 and 66% respectively on low high [K(+)] (25 mM) and 65 and 60% respectively on high [K+] (80 mM). Crude flavonoids showed spasmolytic on both agonists while crude saponins only showed spasmolytic activity on ACh and displayed spasmogenic effect on KCl. Quercetin, quercitrin and rutin exhibited significant antispasmodic effect with IC(50) values <0.1 microg/ml. Epoxygaertneroside and gaertneroside showed good antispasmodic activity on both agonists (4<IC(50)<7 microg/ml).
Morinda morindoides leaves possess spasmogenic and spasmolytic properties that can at least explain and support its traditional use against constipation and diarrhoea respectively.
Journal of ethnopharmacology 11/2009; 127(2):215-20. · 2.32 Impact Factor
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ABSTRACT: The aerial parts of Cressa cretica L. yielded five flavonoids that were identified as quercetin (1), quercetin-3-O-glucoside (2), kampferol-3-O-glucoside (3), kampferol-3-O-rhamnoglucoside (4), and rutin (5). All of the isolated flavonoids were identified by spectroscopic methods (UV, FAB-MS, 1H NMR and 13C NMR) and in comparison with literature data. The isolated flavonoids, except quercetin, are reported here for the first time from Cressa cretica L.
09/2008; 42(4-5):349-352.
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ABSTRACT: A new method was developed and validated for the quantification of strictosamide in the extract of the stem bark of Nauclea pobeguinii. This plant belongs to the Rubiaceae family and is widely used in the African traditional medicine against malaria and malaria-like symptoms. Alkaloids are suspected to be responsible for the antimalarial activity. One of these alkaloids is strictosamide, already reported to be the major constituent in the root bark of this plant. Because strictosamide was not commercially available another alkaloid, ajmalicine HCl, with comparable properties was used as a secondary standard. The samples of the dried 80% ethanol extract from the stem bark of N. pobeguinii were purified on C(18) solid phase extraction cartridges and analysed using HPLC-UV. The strictosamide used for the validation of the correction factor for response was isolated and purified by means of preparative HPLC and TLC. Although the relative standard deviation (R.S.D.) of 2.6% was still acceptable, the response factor was determined for every analysis based on the ratio of the peak area of strictosamide compared to the peak area of ajmalicine HCl in a concentration of 0.01 mg/ml. The precision of the method according to the time and the concentration, had a R.S.D. value of 2.2% and 2.6%, respectively. The recovery of the method was 92.2% (R.S.D. of 9.4%) which was acceptable. The method has been proven to be suitable for the determination of alkaloids in the extract of the stem bark of N. pobeguinii, according to the ICH guidelines on the validation of analytical methods.
Talanta 08/2008; 76(2):462-8. · 3.79 Impact Factor
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ABSTRACT: Saponins are a very diverse and large group of natural compounds, consisting of a glycan moiety linked to a triterpene or a steroid sapogenin. Part of these contain a 13,28-epoxy bridge, where C-28 can be a methylene, a hydroxymethylene or a carbonyl group. This review was restricted to those saponins possessing a completely saturated pentacyclic triterpene skeleton and a 13,28-epoxy bridge, in which C-28 was a methylene or a hydroxymethylene group, excluding the C-28 carbonyl derivatives (28→13 lactones). Almost all of these saponins have been found in members of the Primulaceae or Myrsinaceae plant families. The most important genera were Ardisia, Maesa, and Myrsine from the Myrsinaceae, and Cyclamen, Lysimachia, and Primula from the Primulaceae. Their structures were reviewed, biological activities discussed, and structure-activity relationships established.
Current Organic Chemistry 04/2008; 12(8):629-642. · 3.06 Impact Factor
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ABSTRACT: 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.
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 blueâ 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.
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.
These active plant extracts are selected for extensive studies leading to the isolation of active constituents.
Journal of Ethnopharmacology 03/2008; 115(3):409-15. · 3.01 Impact Factor
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ABSTRACT: After prolonged storage, samples of dihydroartemisinin were found to contain a decomposition product with a molecular weight of 238, as evidenced by MS analysis, the formation of which was accelerated by heating at 60 degrees C for several days. This decomposition product was isolated and identified as 2-(3-oxobutyl)-3-methyl-6-(2-propanal)-cyclohexanon, known to be formed by thermolysis of dihydroartemisinin at 190 degrees C. However, during work-up of this compound a hitherto unknown decomposition product of dihydroartemisinin with a molecular weight of 210 was obtained and identified by 1H, 13C and two-dimensional NMR spectroscopy as 2-(3-oxobutyl)-3-methyl-6-ethyl-cyclohexanon. Most probably this product was formed by oxidation of the aldehyde functionality of the former decomposition product and subsequent decarboxylation.
Pharmazie 01/2008; 62(12):900-1. · 1.01 Impact Factor
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F B Magassouba,
A Diallo,
M Kouyaté,
F Mara,
O Mara,
O Bangoura,
A Camara,
S Traoré,
A K Diallo,
M Zaoro, [......],
K Oularé,
M S Barry,
M Donzo,
K Camara,
K Toté,
D Vanden Berghe,
J Totté, L Pieters,
A J Vlietinck,
A M Baldé
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ABSTRACT: A total of 418 healers have been interviewed in Guinea, a coastal country of West Africa, ranging between 7 degrees 30 and 12 degrees 30 of northern latitude and 8 degrees and 15 degrees of western longitude. Plant species used by the local inhabitants to treat infectious diseases were identified using ethnobotanical, ethnographic and taxonomic methods. During these investigations, 218 plants were registered, of which the following were the most frequently used: Erythrina senegalensis, Bridelia ferruginea, Crossopteryx febrifuga, Ximenia americana, Annona senegalensis, Cochlospermum tinctorium, Cochlospermum planchonii, Lantana camara, Costus afer, Psidium guajava, Terminalia glaucescens, Uapaca somon and Swartzia madagascariensis. Most plants, and especially the leaves, were essentially used as a decoction. In order to assess antibacterial activity, 190 recipes were prepared and biologically tested, among which six showed activity (minimal inhibitory concentration<125 microg/ml) against Bacillus cereus, Mycobacterium fortuitum, Staphylococcus aureus, or Candida albicans, i.e., Entada africana, Chlorophora regia, Erythrina senegalensis, Harrisonia abyssinica, Uvaria tomentosa, and a mixture of six plants consisting of Swartzia madagascariensis, Isoberlinia doka, Annona senegalensis, Gardenia ternifolia, Terminalia glaucescens and Erythrina senegalensis.
Journal of Ethnopharmacology 10/2007; 114(1):44-53. · 3.01 Impact Factor
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ABSTRACT: Over the last decade, much research has focused on the potential health benefits of antioxidants and indeed many synthetic and natural compounds have been evaluated for their antioxidant profile. However, in several studies only a limited number of assays, often poorly validated, are used and the techniques available frequently lack specificity. These limitations may incorrectly influence the results. This review will therefore focus on several pitfalls that may emerge in vitro and in vivo antioxidant research. First, different in vitro techniques to determine antioxidant potential are discussed, including radical scavenging assays and fingerprinting methods. As a rule, a panel of different assays is indispensable to characterize and establish in vitro antioxidant activity. Furthermore, as problems of absorption, distribution, metabolism and excretion are only accounted for by in vivo studies, the need for in vivo antioxidant research is pointed out. Several methods to characterize the in vivo activity of antioxidants, including major drawbacks and pitfalls of some assays, have been discussed. The availability of both a representative “oxidative stress” animal model and a battery of well-validated assays to assess the broad diversity of oxidative damage and antioxidative defence parameters, are crucial for antioxidant research in vivo.
Current Medicinal Chemistry 01/2007; 14(4):417-430. · 4.86 Impact Factor
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Planta Medica 01/2007; 73(9):920-920. · 2.15 Impact Factor
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ABSTRACT: An aqueous decotion (dried extract), an 80% MeOH extract from Morinda morindoides leaves, and 10 flavonoids and 4 iridoids isolated from the 80% MeOH extract were evaluated in vitro for their potential antiamoebic activity and their cytotoxic effect against MT-4 cells. Results indicated that the aqueous decoction and the 80% MeOH extract exhibited an interesting antiamoebic activity with IC(50) values of 3.1 +/- 1.7 and 1.7 +/- 0.6 microg/ml, respectively. Apigenin-7-O-glucoside and luteolin-7-O-glucoside exhibited a moderate antiamoebic activity with IC(50) values of 22.3 +/- 3.2 and 37.4 +/- 2.7 microg/ml, respectively. Kaempferol (IC(50) = 10.3 +/- 2.3 microg/ml), apigenin (IC(50) = 12.7 +/- 4.3 microg/ml), and luteolin (IC(50) = 17.8 +/- 4.3 microg/ml) showed a more pronounced activity than their corresponding glycosides. All tested iridoids displayed a very good activity with IC(50) values less than 10 microg/ml. The most active iridoids were epoxygaertneroside (IC(50) = 1.3 +/- 0.4 microg/ml) and methoxygaertneroside (IC(50) = 2.3. +/- 0.7), followed by gaertneroside and gaertneric acid with IC(50) values of 4.3 +/- 1.8 and 7.1 +/- 1.4 microg/ml, respectively. Except quercetin and quercetin-7,4'-dimethylether which have shown a cytotoxic effect with IC(50) ranging from 14 to 22 microg/ml. No correlation could be deduced between the observed antiamoebic and cytotoxic activity of these tested samples. A structure-activity relationship for isolated compounds is discussed. These findings support the medicinal report for the traditional use of Morinda morindoides leaves for the treatment of amoebiasis.
Journal of Ethnopharmacology 09/2006; 107(1):83-90. · 3.01 Impact Factor
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AM Baldé,
FB Magassouba,
R Barry,
A Loua,
S Traoré,
F Mara,
O Mara,
O Bangoura,
A Camara,
M Kouyaté, [......],
G Mamy,
G Kolomou,
S Mamy,
A Dieng,
MD Barry,
F Soumah,
A Traoré, L Pieters,
J Totté,
AJ Vlietinck
Retrovirology. 01/2006;
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ABSTRACT: 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.
Journal of Ethnopharmacology 11/2005; 102(1):89-94. · 3.01 Impact Factor
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G K Mesia,
G L Tona,
O Penge,
M Lusakibanza,
T M Nanga,
R K Cimanga,
S Apers,
S Van Miert,
J Totte, L Pieters,
A J Vlietinck
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ABSTRACT: The antimalarial activities of crude extracts and 17 fractions from the partition of 80%-methanolic extracts of three plants (the stem bark of Croton mubango, the stem bark of Nauclea pobeguinii and the leaves of Pyrenacantha staudtii) used as antimalarial remedies in the Democratic Republic of Congo were studied both in vitro (against Plasmodium falciparum) and in mice infected with Pl. berghei berghei. The toxic effects of dried aqueous extracts of the plants were also investigated, in uninfected mice. The most active crude extracts in vitro, with median inhibitory concentrations (IC(50)) of <1 microg/ml, were found to be the methanolic and dichloromethane extracts of C. mubango, and the dichloromethane extracts of N. pobeguinii and Py. staudtii. The aqueous extract with the most antimalarial activity in vitro was that of C. mubango (IC(50) = 3.2 microg/ml), followed by that of N. probeguinii (IC(50) = 5.3 microg/ml) and then that of Py. staudii (IC(50) = 15.2 microg/ml). Results from the in-vivo tests of antimalarial activity showed that, at a daily oral dose of 200 mg/kg, all the dichloromethane extracts, the petroleum-ether, chloroformic, ethyl-acetate and residual water-soluble fractions from C. mubango, and the chloroformic, ethyl-acetate and n-butanolic fractions from Py. staudtii produced >80% chemosuppression of the parasitaemias by day 4. The aqueous extracts of C. mubango and N. probeguinii produced a slightly lower but still significant inhibition of parasitaemia (60%-80%) whereas that of Py. staudtii only suppressed the day-4 parasitaemias by 37%. The dried aqueous extract of the stem bark of C. mubango showed some signs of toxicity in mice, with median lethal doses (LD(50)) of 350 mg/kg in the female mice and 900 mg/kg in the male. The extract significantly increased the serum concentrations of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) in mice of both sexes, but had no effect on the blood levels of creatinine or urea. No significant toxic effect was observed for the dried aqueous extracts of N. pobeguinii and Py. staudtii (LD(50) >5 g/kg). Neither of these extracts affected the serum concentrations of GPT or the blood concentrations of creatinine and urea, although the N. pobeguinii extract did increase the serum concentration of GOT.
Annals of Tropical Medicine and Parasitology 06/2005; 99(4):345-57. · 1.43 Impact Factor
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ABSTRACT: The double bond position in long-chain 6-alkenyl salicylic acids has been determined by collisional activation of [M - H + 2Li]+ and [M - H]− precursor ions, which were generated by FAB. The pattern of product ions characteristic for charge-remote fragmentations allowed for a straightforward determination of the location of the double bond for the dilithiated precursor ion species, whereas complications from loss of CO2 were experienced for carboxylate anions. The product ion collisionally activated dissociation spectra obtained for both precursor ion species also reveal the formation of stable radical ions, which are likely distonic and point to the involvement of radical processes in charge-remote fragmentation.
Biological Mass Spectrometry 04/2005; 22(11):647 - 653. · 3.41 Impact Factor
