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

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

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

Antibacterial effects of some Cameroonian medicinal plants against common pathogenic bacteria

We screened forty crude extracts of twenty Cameroonian medicinal plants commonly used to treat bacterial infections for broad spectrum antibacterial activity, as a more affordable alternative against resistant organisms. The extracts were screened on common pathogenic gram negative and gram positive bacteria initially by the disc diffusion method followed by the tube dilution method. Using discs containing 30µg of extract, Escherichia coli showed sensitivity to 23 extracts with diameter of zone of inhibition ranging from 7 – 19mm, fifteen of which were up to or > 10mm. Pseudomonas aeruginosa was sensitive to 11 extracts, whereas Salmonella typhimurium and Staphylococcus aureus were not sensitive to any of the extracts. Based on the zones of inhibition the activity of the extracts were equivalent to 30 to 138 % efficacy of the standard antibiotic discs. The lowest Minimum Inhibitory Concentration (MIC) recorded was 2 mg/ml for Euphorbia hirta against S. aureus and P. aeruginosa and the lowest Minimum Bactericidal Concentration (MBC) was 6 mg/ml for six extracts from Ageratum conyzoides, Aframomum citratum, Euphorbia hirta, Momordica charantia, Mangifera indica and Khaya senegalensis against three bacterial species. Three extracts had broad spectrum bacteriostatic activity (MICs &#8804; 4 mg/ml) while in terms of MBCs none of the extracts showed broad spectrum bactericidal activity. We conclude that most of the tested plants used as traditional antibacterials have a bacteriostatic effect on gram-negative pathogenic bacteria. Keywords: plant extracts, broad spectrum, bacteriostatic, bactericidal African Journal of Traditional, Complementary and Alternative Medicines Vol. 3(2) 2006: 84-9

In vitro screening of 1-aryl-6-hydroxy-1,2,3,4-tetrahydroisoquinolines: Structure related activity against pathogenic bacteria

Objective: To evaluate the antibacterial activity of ten synthetic tetrahydroisoquinolines against eight bacterial strains. Methods: The ten tetrahydroisoquinolines synthesized via base-catalyzed Pictet–Spengler cyclization were screened against a total of eight bacterial strains comprising control and pathogenic strains by the disc diffusion and micro-dilution methods. The most active compound was then assessed for cytotoxicity on human lymphocytes. Results: Six of the tetrahydroisoquinolines showed broad spectrum bacteriostatic activity. The zones of inhibition produced ranged from 7 to 23 mm for 200 μg per disc. The presence of a lipophilic substituent at the para position of the pendant phenyl group conferred the highest antibacterial activity. Compound 2 [1-(3,4-chlorophenyl)-6-hydroxy-1,2,3,4-tetrahydroisoquinoline] was the most active and produced zones ranging from 9 to 20 mm against all eight bacterial strains. Compound 2 also showed the lowest minimum inhibitory concentration of 100 μg/mL against Escherichia coli ATCC11775 and the lowest minimum bactericidal concentration of 800 μg/mL against pathogenic Salmonella typhimurium. Overall, compound 2 was the most active with bacteriostatic and bactericidal activity against three and four bacterial strains respectively. A 50% cytotoxic concentration of 98.2 μg/mL was recorded for compound 2 indicating a low risk of toxicity. Conclusions: The 1-aryl-1,2,3,4-tetrahydroisoquinolines display structure-related antibacterial activity and further chemical exploration of the tetrahydroisoquinoline scaffold may yield more potent non-toxic derivatives for development into new antibacterials