Selective activity of extracts of Margaritaria discoidea and Homalium africanum on Onchocerca ochengi

<p>Abstract</p> <p>Background</p> <p>The current treatment of onchocerciasis relies on the use of ivermectin which is only microfilaricidal and for which resistant parasite strains of veterinary importance are increasingly being detected. In the search for novel filaricides and alternative medicines, we investigated the selective activity of crude extracts of <it>Margaritaria discoidea </it>and <it>Homalium africanum </it>on <it>Onchocerca ochengi</it>, a model parasite for <it>O. volvulus</it>. These plants are used to treat the disease in North West Cameroon.</p> <p>Methods</p> <p>Sixteen crude extracts were prepared from various parts of <it>M. discoidea </it>and <it>H. africanum </it>using different organic solvents. The filaricidal activities were determined <it>in vitro</it>. Cytotoxicity of the active extracts was assessed on monkey kidney epithelial cells <it>in vitro </it>and the selectivity indices (SI) of the extracts determined. Acute toxicity of the promising extracts was investigated in mice.</p> <p>Results</p> <p>Four out of the 16 extracts showed microfilaricidal activity based on motility reduction, whereas, none showed macrofilaricidal activity based on the MTT/formazan assay. The methylene chloride extract of <it>H. africanum </it>leaves (HLC) recorded the lowest IC₅₀of 31.25 μg/mL and an IC₁₀₀of 62.5 μg/mL. The SI for the active extracts ranged from 0.5 - 2.63. No form of acute toxicity was observed in mice. Phytochemical analysis revealed the presence of anthraquinones, sterols and terpenoids in the promising extracts.</p> <p>Conclusions</p> <p>The non-polar extracts of <it>M. discoidea </it>and <it>H. africanum </it>are potential sources of new microfilaricidal lead compounds, and the results support their use in traditional medicine.</p

Isolation and molecular identification of Salmonella with high multidrug resistance to first line typhoid antibiotics in Southwest Cameroon

Background:The prevalence of typhoid fever in Cameroon is high. However, studies on susceptibility of Salmonella to the recommended antibiotics are few and not extensive. This study investigated the susceptibility of Salmonella isolated from clinical specimens in the South West region of Cameroon and the genes responsible for their antibiotic resistance.&nbsp;Methods:&nbsp;Salmonellawas isolated from clinical specimens collected from some medical laboratories in the study area by culture on Salmonella Shigella agar. Identification and resistance genes analysis were done using biochemical tests, PCR and gene sequencing. Disc diffusion test was done using 11 commercial antibiotics and minimum inhibitory concentrations determined by microdilution test to assess antibiotic susceptibility profile. The Multi-Antibiotic Resistance (MAR) index values were calculated.&nbsp;Results:&nbsp;Salmonella was isolated from 50 out of 115 specimens, of which 46 (92 %) were multidrug resistant (MDR) with MAR indices &gt; 0.2.The MDR isolates showed high resistance to penicillins and low resistance to ciprofloxacin. PCR revealed that antibiotic resistance was largely due to the&nbsp;tem-1,&nbsp;Sul 1,&nbsp;dfrA1,&nbsp;floR&nbsp;genes. Sequencing revealed double mutations at codons 83 (Ser83-Phe) and 87 (Asp87-Gly) and one mutation at codon 83 (Ser83-Trp) in the quinolone resistance determining regions of the&nbsp;gyrA gene in two isolates.&nbsp;Conclusion:&nbsp;This study has revealed presence of MDR&nbsp;Salmonella enterica&nbsp;isolates in Southwest Cameroon with several resistance genes.&nbsp;This finding will guide use of antibiotics in treatment of Salmonella infections in the study area and justifies the search for new efficacious antibacterials against the MDR strains

In Vitro Antiplasmodial Activity and Cytotoxicity of Extracts of Selected Medicinal Plants Used by Traditional Healers of Western Cameroon

Medicinal plants play a key role in malaria control in Africa, especially in remote areas where health facilities are limited. In order to assess their acclaimed potentials, eleven extracts were prepared from seven selected plants commonly used in Western Cameroon, and tested both for their antiplasmodial activity and cytotoxicity. The antiplasmodial activity was assessed using Lactate Dehydrogenase Assay (pLDH) and the cytotoxicity estimated on LLC-MK2 monkey kidney epithelial cells. Seven extracts from five different plants were significantly active, with very weak or no cytotoxicity. The Dacryodes edulis leaves showed the highest activity (IC50 of 6.45 μg/mL on 3D7 and 8.2 μg/mL on DD2) followed by the leaves of Vernonia amygdalina (IC50 of 8.72 and 11.27 μg/mL on 3D7 and DD2 resp.) and roots of V. amygdalina (IC50 of 8.72 μg/mL on 3D7), Coula edulis leaves (IC50 of 13.80 μg/mL and 5.79 μg/mL on 3D7 and DD2 resp.), Eucalyptus globulus leaves (IC50 of 16.80 μg/mL and 26.45 μg/mL on 3D7 and DD2) and Cuviera longiflora stem bark (IC50 of 20.24 μg/mL and 13.91 μg/mL on 3D7 and DD2). These findings justify the use of five of the seven plants in malaria treatment by traditional healers of Western Cameroon

Antiplasmodial activities of some products from Turreanthus africanus (Meliaceae)

We investigated the antiplasmodial activity of some pure compounds of Turreanthus africanus (Meliaceae), a plant that is used in traditional medicine to treat malaria in Southwest Cameroon. A phytochemical analysis of the methylene chloride: methanol (1:1) extract of the seeds of the plant yielded seven compounds. Four of them, which were oils, were subjected to in vitro bioassays on Plasmodium falciparum F 32, chloroquine sensitive strain. Compound 1 (16-oxolabda-8 (17), 12(E)-dien-15-oic acid), showed the highest antiplasmodial activity, two others (methyl-14,15-epoxylabda-8 (17), 12(E)-diene-16-oate, and turreanin A), had moderate activity and one was inactive. These findings are consistent with the use of T. africanus in the traditional treatment of P. falciparum malaria. African Journal of Health Sciences Vol. 13 (1-2) 2008: pp. 32-3

THE ANTIMALARIAL POTENTIAL OF MEDICINAL PLANTS USED FOR THE TREATMENT OF MALARIA IN CAMEROONIAN FOLK MEDICINE

Malaria remains one of the leading public health problems in Cameroon as in other parts of Sub-Saharan Africa. In the past decades, this situation has been aggravated by the increasing spread of drug-resistant Plasmodium falciparum strains. New antimalarial drug leads are therefore urgently needed. Traditional healers have long used plants to prevent or cure infections. This article reviews the current status of botanical screening efforts in Cameroon as well as experimental studies done on antimalarial plants. Data collected from 54 references from various research groups in the literature up to June 2007 shows that 217 different species have been cited for their use as antimalarials in folk medicine in Cameroon. About a hundred phytochemicals have been isolated from 26 species some among which are potential leads for development of new antiamalarials. Crude extracts and or essential oils prepared from 54 other species showed a wide range of activity on Plasmodium spp. Moreover, some 137 plants from 48 families that are employed by traditional healers remain uninvestigated for their presumed antimalarial properties. The present study shows that Cameroonian flora represents a high potential for new antimalarial compounds. Further ethnobotanical surveys and laboratory investigations are needed to fully exploit the potential of the identified species in the control of malaria

Antiplasmodial Activities of Some Products from Turreanthus Africanus (Meliaceae)

We investigated the antiplasmodial activity of some pure compounds of Turreanthus africanus (Meliaceae), a plant that is used in traditional medicine to treat malaria in Southwest Cameroon. A phytochemical analysis of the methylene chloride: methanol (1:1) extract of the seeds of the plant yielded seven compounds. Four of them, which were oils, were subjected to in vitro bioassays on Plasmodium falciparum F 32, chloroquine sensitive strain. Compound 1 (16-oxolabda-8 (17), 12(E)-dien-15-oic acid), showed the highest antiplasmodial activity, two others (methyl-14,15-epoxylabda-8 (17), 12(E)-diene-16-oate, and turreanin A), had moderate activity and one was inactive. These findings are consistent with the use of T. africanus in the traditional treatment of P. falciparum malaria

Chemical constituents and mosquito larvicidal properties of leaf extracts and fractions of Quassia amara linn against Anopheles gambiae

This study evaluated the larvicidal efficacy of the crude methanol extract of the leaves of Quassia amara and the hexane, chloroform and ethyl acetate fractions partitioned based on their polarities, against the fourth instar larvae of Anopheles gambiae. Larvicidal studies were carried out on larvae collected from mosquito breeding sites, at concentrations ranging from 125 to 2000 μg/mL for the crude extract, 125 to 500 μg/mL for the partitioned fractions and 7.5 to 120 μg/mL for the sub-fractions. Larvae were exposed to extracts/fractions for 24 h. The percentage mortalities were calculated and the LC50 values were obtained using GraphPad Prism, a nonlinear regression analysis. The&nbsp; structures of compounds present in the active fractions were elucidated using spectroscopic techniques. The crude methanol extract was toxic to the larvae displaying 100 % mortality at 2000 μg/mL and an LC50 of 640 μg/mL. Results were concentration dependent. The LC50 values for the hexane and chloroform soluble fractions were 37.38 and 283 μg/mL respectively. The ethyl acetate fraction had a percentage mortality of &lt;50 % at the highest dose tested. Further bioactivity led chromatographic separation of the hexane soluble fraction (LC50= 17.84 μg/mL) obtained methyl gallate. Results obtained from this study suggest that Q. amara could serve as an alternative to synthetic larvicides. Keywords: Quassia amara, Anopheles gambiae, larvae, extracts, methyl gallate, toxicit

The Antimalarial Potential Of Medicinal Plants Used For The Treatment Of Malaria In Cameroonian Folk Medicine

Malaria remains one of the leading public health problems in Cameroon as in other parts of Sub-Saharan Africa. In the past decades, this situation has been aggravated by the increasing spread of drug-resistant Plasmodium falciparum strains. New antimalarial drug leads are therefore urgently needed. Traditional healers have long used plants to prevent or cure infections. This article reviews the current status of botanical screening efforts in Cameroon as well as experimental studies done on antimalarial plants. Data collected from 54 references from various research groups in the literature up to June 2007 shows that 217 different species have been cited for their use as antimalarials in folk medicine in Cameroon. About a hundred phytochemicals have been isolated from 26 species some among which are potential leads for development of new antiamalarials. Crude extracts and or essential oils prepared from 54 other species showed a wide range of activity on Plasmodium spp. Moreover, some 137 plants from 48 families that are employed by traditional healers remain uninvestigated for their presumed antimalarial properties. The present study shows that Cameroonian flora represents a high potential for new antimalarial compounds. Further ethnobotanical surveys and laboratory investigations are needed to fully exploit the potential of the identified species in the control of malaria

Anti-onchocercal and antibacterial Activities of crude extracts and Secondary Metabolites from the Rhizome of Anchomanes difformis (Araceae)

The methanol (MeOH) extract of Anchomanes difformis(Araceae) was fractionated by column chromatography and some pure compounds were obtained whose structures were determined by 1H and 13C-NMR spectroscopy. The extract was tested in vitro for anti-onchocercal activity against O. ochengi, a close relative of O. vulvolus. The MeOH extract showed 100% inhibition of O. ochengi microfilarial activity. Compounds 1, 2 and 3 which were identified as (Z)-12-heptadecenoic acid (1), hexadecanoic acid (2) and â-stigmasterol (3) showed no anti-onchocercal activity against the microfilariae, but 1 and 2 showed weak antibacterial activity against E. coli with erythromycin included as reference.The present study constitutes the first report on the antifilarial activity of Anchomanes difformis and lends credence to the traditional use of juice from the rhizome in the management of river blindness.Key words: Anchomanes difformis, Onchocerciasis, Antibacterial, Antifilaria