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1.
J Ethnopharmacol ; 235: 111-121, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-30738118

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Annona muricata (Annonaceae) is a commonly used medicinal plants in Cameroonian traditional medicines to treat various diseases including malaria. Previous studies have shown that extracts from this plant have antiplasmodial activity. AIM OF THE STUDY: This study aimed to explore the endophyic fungi associated with some parts of this plant for their ability to produce antiplasmodial metabolites. MATERIALS AND METHODS: One hundred and fifty-two endophytic fungi isolated from twelve different organs of A. muricata were cultured and the ethyl acetate extracts of conditioned media screened for antiplasmodial activity using the 96-well microtiter plate format SYBR green florescence assay against Chloroquine-sensitive Pf3D7 and Chloroquine-resistant PfINDO/PfDd2 strains of Plasmodium falciparum. RESULTS: Twenty-seven (17.76%) of fungi tested were found to completely inhibit the growth of Plasmodium parasites at 10 µg/mL. The 5.8S rDNA sequencing data revealed the strongly active (IC50 < 2 µg/mL against at least 2 P. falciparum strains) isolates to be Trichoderma afroharzianum AMrb7, Penicillium citrinum AMrb11, Neocosmospora rubicola AMb22, Penicillium tropicum AMb3, Penicillium citrinum AMrb23, Aspergillus versicolor AMb7, and Fusarium sp AMst1. Of these, the extracts from Penicillium citrinum AMrb11 (IC50 0.84-0.93 µg/mL) and Neocosmospora rubicola AMb22 (IC50 0.39-1.92 µg/mL) showed the highest promise against all three plasmodial strains with selectivity indices ranging from 34.71 to 180.97. Dynamic head space GC-MS analysis of ethyl acetate extracts of promising fungi revealed broad-spectrum antimicrobial compounds such as Penicidin, Aromadendrene, Ethyl p-methoxycinnamate, 2-Coumaranone and 2-Methyl resorcinol. CONCLUSION: These results have opened new avenues for discovery of novel antimalarial lead compounds from endophytic fungi associated with Annona muricata - a medicinally important plant.


Assuntos
Annona/microbiologia , Antimaláricos/farmacologia , Fungos/isolamento & purificação , Plasmodium falciparum/efeitos dos fármacos , Antimaláricos/administração & dosagem , Antimaláricos/isolamento & purificação , Camarões , Cloroquina/farmacologia , Descoberta de Drogas/métodos , Endófitos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Concentração Inibidora 50 , Medicina Tradicional Africana/métodos
2.
Parasitol Res ; 117(8): 2473-2485, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29797084

RESUMO

Plasmodial resistance to artemisinin-based combination therapies emphasizes the need for new drug development to control malaria. This paper describes the antiplasmodial activity of metabolites produced by endophytic fungi of three Cameroonian plants. Ethyl acetate extracts of fungi cultivated on three different media were tested against Plasmodium falciparum chloroquine-sensitive (Pf3D7) and chloroquine-resistant (PfINDO) strains using the SYBR green florescence assay. Selected endophytes were further grown in potato dextrose broth supplemented with small organic elicitors and their extracts tested for activity. The effect of elicitors on de novo metabolite synthesis was assessed by reverse-phase HPLC. Activity screening of 81 extracts indicated that Aspergillus niger 58 (IC50 2.25-6.69 µg/mL, Pf3D7), Fusarium sp. N240 (IC50 1.62-4.38 µg/mL, Pf3D7), Phomopsis sp. N114 (IC50 0.34-7.26 µg/mL, Pf3D7), and Xylaria sp. N120 (IC50 2.69-6.77 µg/mL, Pf3D7) produced potent extracts when grown in all three media. Further culture of these endophytes in potato dextrose broth supplemented with each of the eight small organic elicitors and subsequent extracts screening indicated the extract of Phomopsis sp. N114 grown with 1% 1-butanol to be highly selective and extremely potent (IC50 0.20-0.33 µg/mL; SI > 666). RPHPLC profiles of extracts of Phomopsis sp. N114 grown with or without 1-butanol showed some peaks of enhanced intensities in the former without any qualitative change in the chromatograms. This study showed the ability of selected endophytes to produce potent and selective antiplasmodial metabolites in varied culture conditions. It also showed how the production of desired metabolites can be enhanced by use of small molecular weight elicitors.


Assuntos
Antimaláricos/farmacologia , Aspergillus niger/metabolismo , Cananga/microbiologia , Extratos Celulares/farmacologia , Fusarium/metabolismo , Plasmodium falciparum/efeitos dos fármacos , Terminalia/microbiologia , Xylariales/metabolismo , Antimaláricos/metabolismo , Artemisininas/farmacologia , Aspergillus niger/isolamento & purificação , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Camarões , Cloroquina/farmacologia , Meios de Cultivo Condicionados , Fusarium/isolamento & purificação , Malária/tratamento farmacológico , Testes de Sensibilidade Parasitária , Extratos Vegetais/farmacologia , Plantas Medicinais/microbiologia , Xylariales/isolamento & purificação
3.
Nat Prod Res ; 32(6): 640-647, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28540745

RESUMO

Reverse transcriptase (RT)-associated DNA polymerase (RDDP) and ribonucleaser H (RNase H) functions are both essential for HIV-1 genome replication, and the identification of new inhibitors to block both of them is a goal actively pursued by the scientific community. In this field, natural extracts have shown a great potential as source of new antivirals. In the present work, we investigated the effect of Uvaria angolensis extracts on the HIV-1 reverse transcriptase-associated DNA polymerase and ribonuclease H activities. The U. angolensis stem bark methanol extract inhibit both HIV-1 RNase H function and RDDP activity with IC50 values of 1.0 ± 0.2 and 0.62 ± 0.15 µg/mL, respectively and, after been fractionated with different solvents, its solid residue showed an IC50 of 0.10 ± 0.03 and of 0.23 ± 0.04 µg/mL against RNase H and RDDP, respectively, hence laying the bases for further studies for identification of single active components.


Assuntos
Fármacos Anti-HIV/farmacologia , Transcriptase Reversa do HIV/antagonistas & inibidores , Inibidores da Transcriptase Reversa/farmacologia , Ribonuclease H/antagonistas & inibidores , Uvaria/química , Fármacos Anti-HIV/química , Linhagem Celular , Fracionamento Químico , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Concentração Inibidora 50 , Casca de Planta/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , DNA Polimerase Dirigida por RNA/metabolismo , Inibidores da Transcriptase Reversa/química
4.
Medicines (Basel) ; 4(1)2017 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-28930221

RESUMO

Background: Pathogenic yeasts resistance to current drugs emphasizes the need for new, safe, and cost-effective drugs. Also, new inhibitors are needed to control the effects of enzymes that are implicated in metabolic dysfunctions such as cancer, obesity, and epilepsy. Methods: The anti-yeast extract from Terminalia mantaly (Combretaceae) was fractionated and the structures of the isolated compounds established by means of spectroscopic analysis and comparison with literature data. Activity was assessed against Candida albicans, C. parapsilosis and C. krusei using the microdilution method, and against four enzymes of metabolic significance: glucose-6-phosphate dehydrogenase, human erythrocyte carbonic anhydrase I and II, and glutathione S-transferase. Results: Seven compounds, 3,3'-di-O-methylellagic acid 4'-O-α-rhamnopyranoside; 3-O-methylellagic acid; arjungenin or 2,3,19,23-tetrahydroxyolean-12-en-28-oïc acid; arjunglucoside or 2,3,19,23-tetrahydroxyolean-12-en-28-oïc acid glucopyranoside; 2α,3α,24-trihydroxyolean-11,13(18)-dien-28-oïc acid; stigmasterol; and stigmasterol 3-O-ß-d-glucopyranoside were isolated from the extract. Among those, 3,3'-di-O-methylellagic acid 4'-O-α-rhamnopyranoside, 3-O-methylellagic acid, and arjunglucoside showed anti-yeast activity comparable to that of reference fluconazole with minimal inhibitory concentrations (MIC) below 32 µg/mL. Besides, Arjunglucoside potently inhibited the tested enzymes with 50% inhibitory concentrations (IC50) below 4 µM and inhibitory constant (Ki) <3 µM. Conclusions: The results achieved indicate that further SAR studies will likely identify potent hit derivatives that should subsequently enter the drug development pipeline.

5.
J Ethnobiol Ethnomed ; 13(1): 33, 2017 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-28595645

RESUMO

BACKGROUND: The combined efforts to combat outdoor/indoor transmission of malaria parasites are hampered by the emerging vector resistance in a wide variety of malaria-endemic settings of Africa and the rest of the world, stressing the need for alternative control measures. This study aimed at documenting insect's repellent plant species used by indigenous populations of 6 localities of East, South, West and Centre regions of Cameroon. METHODS: Information was gathered through face-to-face interviews guided by a semi-structured questionnaire on the knowledge of medicinal plants with insect repellent properties. RESULTS: A total of 182 informants aged from 25 to 75 years were recruited by convenience from May to June 2015. The informants had general knowledge about insects' repellent plants (78.6%). A total of 16 plant species were recorded as insects' repellents with 50% being trees. The most cited plants were Canarium schweinfurthii (Burseraceae) (in four localities, 58/182), Elaeis guineensis (Arecaceae) (in three localities, 38/182), Chromolaena odorata (Compositae) (16/182) and Citrus limon (Rutaceae) (11/182) in two localities each. Among the repellent plant species recorded, 50% were reported to be burnt to produce in-house smokes, 31.2% were mashed and applied on the body, and 18.8% were hung in the houses. The leaf was the most commonly used plant part (52.9%), followed by the bark (17.6%). CONCLUSIONS: This study has shown that rural populations of the 6 targeted localities possess indigenous knowledge on repellent plants that are otherwise cost-effective and better choice for repelling insects including malaria-transmitting mosquitoes. Meanwhile, such practices should be validated experimentally and promoted as sustainable malaria transmission control tools in the remotely located communities.


Assuntos
Etnobotânica , Repelentes de Insetos/farmacologia , Malária/prevenção & controle , Plantas Medicinais , Adulto , Idoso , Camarões , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
6.
Med Mycol ; 55(5): 546-554, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27744307

RESUMO

The molecular epidemiology and the antifungal susceptibility profiles of Candida albicans are scarce in Cameroon. Authors studied the genetic diversity and the antifungal susceptibility of C. albicans isolates from Yaoundé HIV-infected patients. Clinical isolates were obtained by mycological diagnosis of oropharyngeal swabs, stools, urine, and vaginal swabs from patients. C. albicans isolates were confirmed by the Light cycler real-time PCR of the ITS1 region of the 5.8s ribosomal DNA. The ABC genotypes and the Hwp1 gene amplification were carried out with specific primers. Microsatellite length polymorphism of HIS3, CDC3, and EF3 microsatellites was analysed. The antifungal susceptibility testing was carried out by the CLSI broth microdilution M27-A3 and M27-S4 protocols. The minimal inhibitory concentration (MIC) results were interpreted according to updated clinical breakpoints (CBPs) recommended by the CLSI or epidemiological cut-off values (ECVs). One hundred and thirteen (113) isolates were obtained from the analysis of 1218 samples. The ABC genotyping showed 79 (69.91%) genotype A, 24 (21.23%) genotype B, and 10 (8.84%) genotype C. The Hwp1 gene amplification provided a newly observed genetic polymorphism, named H and 5 genotypes described (H1-H5). The microsatellite analysis generated 65 molecular types. All the isolates were susceptible to amphotericin B (MIC ≤ 1 µg/ml); 79.64% of isolates were wild type to itraconazole (MIC ≤ 0.12 µg/ml); and 86.72% of isolates were susceptible to fluconazole (MIC ≤ 2 µg/ml). These results highlight the important genetic diversity of C. albicans isolates among Yaoundé HIV-infected patients and bring clues for the comprehension of the molecular epidemiology of the yeast in Cameroon.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Genes Fúngicos/genética , Variação Genética , Infecções por HIV/complicações , Repetições de Microssatélites/genética , Camarões , Candida albicans/classificação , Candida albicans/isolamento & purificação , Farmacorresistência Fúngica , Proteínas Fúngicas/genética , Genótipo , Humanos , Glicoproteínas de Membrana/genética , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Tipagem Molecular , Reação em Cadeia da Polimerase em Tempo Real
7.
J Med Microbiol ; 65(7): 579-589, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27100672

RESUMO

Cryptococcal meningitis is a dreadful opportunistic fungal infection amongst human immunodeficiency virus (HIV)-infected patients. One complication in the management of the disease is the possible infection of a patient by two or more different strains of Cryptococcus neoformans. This study investigated the intra-individual genetic diversity and antifungal susceptibility of C. neoformans isolates from Yaoundé (Cameroon) HIV-infected patients with cryptococcal meningitis. Twenty-five clinical isolates were obtained during a prospective study. Five colonies were randomly collected from each initial sample. The 150 isolates obtained (125 colonies and 25 initial samples) were submitted to serotyping by multiplex PCR. Genotyping analyses were achieved using RFLP, and minisatellite- and microsatellite-length polymorphism. The antifungal susceptibility testing was carried out using a Sensititre YeastOne kit. Seven antifungals were tested: itraconazole, fluconazole, amphotericin B, ketoconazole, 5-fluorocytosine, posaconazole and voriconazole. The 150 isolates were identified as C. neoformans serotype A and genotype VNI. The microsatellite and minisatellite sequence analyses generated 15 genotypes. Six out of 25 (24 %) patients were found to be infected by two different genotypes. Antifungal susceptibility showed several profiles: posaconazole (0.015-0.25 µg ml-1), amphotericin B (0.06-1 µg ml-1), fluconazole (0.5-16 µg ml-1), itraconazole (0.008-0.12 µg ml-1), ketoconazole (0.008-0.12 µg ml-1), 5-fluorocytosine (0.25-16 µg ml-1) and voriconazole (0.008-0.12 µg ml-1). It was noted that isolates from the same patient might present different susceptibility profiles to an antifungal drug with differences of more than four dilutions. The results achieved highlighted the possible presence of isolates with different genotypes in a patient with dissimilar antifungal susceptibility profiles during a single episode of cryptococcal meningitis.


Assuntos
Antifúngicos/farmacologia , Coinfecção/microbiologia , Cryptococcus neoformans/classificação , Farmacorresistência Fúngica , Variação Genética , Infecções por HIV/complicações , Meningite Criptocócica/microbiologia , Adulto , Idoso , Camarões , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/genética , Cryptococcus neoformans/isolamento & purificação , Feminino , Genótipo , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Tipagem Molecular , Reação em Cadeia da Polimerase Multiplex , Técnicas de Tipagem Micológica , Fenótipo , Polimorfismo de Fragmento de Restrição , Estudos Prospectivos
8.
Int J Mycobacteriol ; 5 Suppl 1: S204-S205, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28043556

RESUMO

AIM AND OBJECTIVES: Buruli ulcer (BU) is a neglected tropical disease caused by a mycobacteria, Mycobacterium ulcerans. The WHO recommended Rifampicin-Streptomycin combination side effects and poor compliance, leaves rural populations with no choice than to patronise indigenous remedies. This study is aimed at validating medicinal plants used in traditional medicine to treat BU by investigating the in vitro efficacy and safety as well as their composition in active molecules. METHODS: A short report-based survey was used to identify medicinal plants used traditionally for BU treatment. Maceration of collected plant samples in methanol, hydroethanolic, ethanol, dichloromethane, and hexane, resulted in a total of 67 extracts assessed for antimycobacteria activity against Mycobacterium smegmatis and Mycobacterium ulcerans using the Resazurin Microtiter Assay. The cytotoxicity effect of promising extracts was assessed on normal human liver cells using the MTT assay. The bio-guided fractionation of the promising extracts led to the isolation of active compounds. RESULTS: Majority of plants prepared as infusion, decoction, poultice, and macerate were administered topically. Significant antimycobacterial activity with MIC values ranging from 16 to 250µg/mL was recorded against M. smegmatis (25 extracts) and M. ulcerans (17 extracts).1 Most of antimycobacterial extracts showed no significant cytotoxicity against normal human hepatocytes.1 The isolation guided by the biological activity revealed nine compounds with significant in vitro anti-M. ulcerans activity (MIC=16-128µg/mL). CONCLUSIONS: The results completed support the use these plants in the indigenous knowledge against BU. Further analyses of active principles might lead to new drug toe fight against BU.

9.
Int J Mycobacteriol ; 5 Suppl 1: S206-S207, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28043557

RESUMO

OBJECTIVE/BACKGROUND: Mycobacterial infections including tuberculosis, leprosy, and buruli ulcer are among the most prevalent, debilitating, and deadly tropical diseases, especially in Sub-Saharan Africa. The development of drug resistance to the currently available drugs and the poor compliance emphasize the need for new chemotherapeutic agents. This study was designed to evaluate the in vitro activity of Cleistopholis patens, Annona reticulata, and Greenwayodendron suaveolens against Mycobacterium smegmatis. The safety on normal liver cells was also assessed. METHODS: The crude extracts, fractions, and subfractions were tested against M. smegmatis and for cell cytotoxicity on WRL-68, normal human hepatocyte using microdilution resazurin-based assays. The phytochemical screening was performed using standard methods. RESULTS: Most of the extracts, fractions, and subfractions inhibited the growth of M. smegmatis with minimum inhibitory concentration (MIC) values ranging from 6.25µg/mL to 125µg/mL. The subfractions P12 and P29 from G. suaveolens twig were more potent with MIC values of 6.25µg/mL and 25µg/mL, respectively. Fruit crude extract and root CH2Cl2 fraction from A. reticulata also showed activity with MIC values of 50µg/mL and 25µg/mL, respectively. Crude extracts from the twig and stem bark of C. patens displayed inhibition at MIC values of 125µg/mL and 100µg/mL, respectively. Majority of active extracts showed no cell cytotoxicity, except the extract from C. patens with IC50 ranging from 41.40µg/mL to 93.78µg/mL. The chemical investigation of the promising extracts revealed the presence of phenols, alkaloids, glycosides, triterpenes, and acetogenins. CONCLUSION: The results achieved from this preliminary antimycobacterial drug discovery study supported the traditional claims of C. patens, A. reticulata, and G. suaveolens in the treatment of mycobacterial infections. Meanwhile, further fractionation is required to characterize the active ingredients.

10.
Phytochemistry ; 117: 521-526, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26232555

RESUMO

During a study on the chemistry and biological activity of Antrocaryon klaineanum Pierre, six new sterols including 4,24(28)-ergostadiene-6α,7α-diol (1), 6α-methoxy-4,24(28)-ergostadiene-7α,20S-diol (2), 6α-methoxy-4,24(28)-ergostadien-7α-ol (3), 20S-hydroxy-24(28)-ergosten-3-one (4), 7α-hydroxy-4,24(28)-ergostadien-3-one (5), and 24(28)-ergostene-3ß,6α-diol (6) were characterized by physical and spectroscopic means. The known steroids 7 and 8 were also isolated. The crude extract and the isolated compounds were evaluated for their ability to inhibit the 3D7 strain of Plasmodium falciparum. Compounds 2, 3, and 8 showed potent activity while that of the crude extract was moderate.


Assuntos
Anacardiaceae/química , Antimaláricos/química , Antimaláricos/farmacologia , Esteroides/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Ergosterol/análogos & derivados , Ergosterol/química , Ergosterol/isolamento & purificação , Ergosterol/farmacologia , Concentração Inibidora 50 , Estrutura Molecular , Casca de Planta/química , Extratos Vegetais/análise , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Esteroides/química
11.
J Ethnopharmacol ; 172: 297-311, 2015 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-26099634

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Buruli ulcer (BU) is the third most common mycobacterial infection in the world, after tuberculosis and leprosy and has recently been recognized as an important emerging disease. This disease is common in West Africa where more than 99% of the burden is felt and where most affected people live in remote areas with traditional medicine as primary or only option. Reports indicate that the ethnopharmacological control approach of the disease in such settings has shown promise. However, no or very few compilations of traditional knowledge in using medicinal plants to treat BU have been attempted so far. This review aimed to record medicinal plants used traditionally against BU in three countries in West Africa: Ivory Coast, Ghana and Benin and for which ethnopharmacological knowledge supported by pharmacological investigations has been reported. The information recorded in this review will support further pharmacological research to develop appropriate drugs for a better BU control. MATERIAL AND METHODS: A systematic review of the literature on ethnobotanical use and anti-BU activity of plants reported for BU treatment was performed. The approach consisted to search several resources, including Technical Reports, Books, Theses, Conference proceedings, web-based scientific databases such as publications on PubMed, Science direct, Springer, ACS, Scielo, PROTA, Google and Google scholar reporting ethnobotanical surveys and screening of natural products against Mycobacterium ulcerans. This study was limited to papers and documents published either in English or French reporting ethnopharmacological knowledge in BU treatment or pharmacological potency in vitro. This review covered the available literature up to December 2014. RESULTS: The majority of reports originated from the three most affected West African countries (Cote d'Ivoire, Ghana and Benin). Though, 98 plant species belonging to 48 families have been identified as having anti-BU use, many have received no or little attention. Most of the pharmacological studies were performed only on 54 species. To a lesser extent, ethnopharmacological knowledge was validated in vitro for only 13 species. Of those, seven species including Ricinus comminus, Cyperus cyperoides (cited as Mariscus alternifolius), Nicotiana tabacum, Mangifera indica, Solanum rugosum, Carica papaya, and Moringa oleifera demonstrated efficacy in hospitalised BU patients. Four isolated and characterized compounds were reported to have moderate bioactivity in vitro against M. ulcerans. CONCLUSIONS: This review compiles for the first time ethnopharmacologically useful plants against BU. The phamacological potential of 13 of them has been demonstrated in vitro and support BU evidence-based traditional medicines. In addition, 7 species showed activity in BU patients and have emerged as a promising source of the traditional medicine for treatment of BU. Yet, further safety and efficacy study should be initiated prior any approval as alternative therapy. Overall, a huge gap in knowledge appeared, suggesting further well-planned and detailed investigations of the in vitro, in vivo, and safety properties of the claimed anti-BU plants. Therefore, plants with medicinal potential should be scrutinized for biologically active compounds, using bioassay-guided fractionation approach to provide new insights to find novel therapeutics for BU control.


Assuntos
Úlcera de Buruli/tratamento farmacológico , Preparações de Plantas/uso terapêutico , Plantas Medicinais/química , África Ocidental , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Úlcera de Buruli/microbiologia , Etnofarmacologia , Humanos , Mycobacterium ulcerans/efeitos dos fármacos , Mycobacterium ulcerans/isolamento & purificação , Preparações de Plantas/farmacologia
12.
J Pharmacol Toxicol Methods ; 73: 27-33, 2015 May-Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25792087

RESUMO

Buruli ulcer (BU) caused by Mycobacterium ulcerans is the third most common chronic mycobacterial infection in humans. Approximately 5000 cases are reported annually from at least 33 countries around the globe, especially in rural African communities. Even though anti-mycobacterial therapy is often effective for early nodular or ulcerative lesions, surgery is sometimes employed for aiding wound healing and correction of deformities. The usefulness of the antibiotherapy nonetheless is challenged by huge restrictive factors such as high cost, surgical scars and loss of income due to loss of man-hours, and in some instances employment. For these reasons, more effective and safer drugs are urgently needed, and research programs into alternative therapeutics including investigation of natural products should be encouraged. There is the need for appropriate susceptibility testing methods for the evaluation of potency. A number of biological assay methodologies are in current use, ranging from the classical agar and broth dilution assay formats, to radiorespirometric, dye-based, and fluorescent/luminescence reporter assays. Mice, rats, armadillo, guinea pigs, monkeys, grass cutters and lizards have been suggested as animal models for Buruli ulcer. This review presents an overview of in vitro and in vivo susceptibility testing methods developed so far for the determination of anti-Buruli ulcer activity of natural products and derivatives.


Assuntos
Antiulcerosos/uso terapêutico , Produtos Biológicos/uso terapêutico , Úlcera de Buruli/tratamento farmacológico , Modelos Animais , Mycobacterium ulcerans , Animais , Ansiolíticos/farmacologia , Ansiolíticos/uso terapêutico , Antiulcerosos/farmacologia , Tatus , Produtos Biológicos/farmacologia , Úlcera de Buruli/patologia , Avaliação Pré-Clínica de Medicamentos/métodos , Cobaias , Humanos , Camundongos , Mycobacterium ulcerans/efeitos dos fármacos , Ratos , Especificidade da Espécie
13.
J Ethnopharmacol ; 162: 306-16, 2015 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-25576895

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Ethnopharmacological surveys were conducted in two regions of Gabon. This led to highlighting some of the medicinal plants used by local populations in the management of HIV/AIDS opportunistic diseases. Two regions with the highest occurrence of HIV/AIDS cases were visited and ethnopharmarcological data was gathered. These regions were the Estuaire Province (Libreville and its neighborhood) and the Haut-Ogooué Province (Franceville and its neighborhood). The opportunistic diseases and symptomatic conditions considered during this study were: diarrhea, respiratory tract infections, cough, tuberculosis, abscesses, stomach ache, skin rashes, venereal diseases, typhoid fever, anemia, general tiredness, hepatitis and vomiting. MATERIALS AND METHODS: The reported species were evaluated through three parameters: specificity, reliability and frequency. Plant parts of relevant species were harvested and extracted with an aqueous alcohol solution (ethanol/water: 1/1). The extracts obtained were submitted to phytochemical screening and in vitro microbiological assays on some clinical isolates and ATCC strains, involved in HIV/AIDS opportunistic diseases through the Agar well diffusion and Microbroth dilution methods. RESULTS: Among the 52 species identified during this survey, Coelocaryon klainei Pierre ex Heckel (Myristicaceae), Dacryodes klaineana (Pierre) H.J. Lam (Bursecaceae), Phyllanthus diandrus Pax (Euphorbiaceae), Saccoglotys gabonensis (Baill.) Urb. (Humiriaceae) and Tetrorchidium didymostemon (Baill.) Pax & K. Hoffm. (Euphorbiaceae) were submitted to in vitro microbiological assays. Phyllanthus diandrus bark and leaves show best antibacterial activities against Pseudomonas aeruginosa and Klebsiella pneumoniae with MIC value of 0.25 respectively. Phytochemical screening revealed the presence in all the plant parts extracts of potentially bioactive molecules, including polyphenols, especially flavonoids and tannins. CONCLUSION: It is concluded that some of these plants might be submitted to further scientific studies, including the identification and isolation of bioactive principles, that could be developed to drugs for the treatment of HIV/AIDS opportunistic diseases.


Assuntos
Etnofarmacologia , Infecções por HIV/terapia , Extratos Vegetais/uso terapêutico , Plantas Medicinais/classificação , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Gabão , Humanos , Fitoterapia , Extratos Vegetais/química , Plantas Medicinais/química
14.
Biomed Res Int ; 2015: 917086, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26779539

RESUMO

Mycobacterium ulcerans disease has been a serious threat for people living in rural remote areas. Due to poverty or availability of traditional medicine these populations rely on herbal remedies. Currently, data on the anti-Mycobacterium ulcerans activity of plants, so far considered community-based knowledge, have been scientifically confirmed, concomitantly with some medicinal plants used to treat infectious diseases in general. Products derived from plants usually responsible for the biological properties may potentially control Mycobacterium ulcerans disease; numerous studies have aimed to describe the chemical composition of these plant antimicrobials. Thus, the present work provides the first compilation of medicinal plants that demonstrated inhibitory potential on Mycobacterium ulcerans. This work shows that the natural products represent potential alternatives to standard therapies for use as curative medicine for Mycobacterium ulcerans disease.


Assuntos
Infecções por Micobactéria não Tuberculosa/tratamento farmacológico , Mycobacterium ulcerans/efeitos dos fármacos , Extratos Vegetais/uso terapêutico , Humanos , Infecções por Micobactéria não Tuberculosa/microbiologia , Mycobacterium ulcerans/patogenicidade , Extratos Vegetais/química , Plantas Medicinais/química
15.
Medicines (Basel) ; 2(2): 55-66, 2015 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-28930201

RESUMO

The aim of this work was to screen extracts from Annona muricata and Annona reticulata in vitro against Plasmodium falciparum. Crude ethanolic extracts, methylene chloride fractions, aqueous fractions, subfractions and isolated compounds (stigmasterol-3-O-ß-d-glucopyranoside, lichexanthone, gallic acid and ß-sitosterol-3-O-ß-d-glucopyranoside) were tested for cytotoxicity on erythrocytes and Human Foreskin Fibroblasts cells and against the W2 strain of P. falciparum in culture. Results indicated that none of the extracts was cytotoxic at concentrations up to 10 µg/mL. Most of the extracts, fractions and subfractions inhibited the growth of P. falciparum with IC50 values ranging from 0.07 to 3.46 µg/mL. The most potent was the subfraction 30 from A. muricata stem bark (IC50 = 0.07 µg/mL) with a selectivity index of ˃ 142. Subfraction 3 from A. muricata root also exhibited very good activity (IC50 = 0.09 µg/mL) with a high selectivity index (SI ˃ 111). Amongst the isolated compounds, only gallic acid showed activity with IC50 of 3.32 µg/mL and SI > 10. These results support traditional claims for A. muricata and A. reticulata in the treatment of malaria. Given their limited cytotoxicity profile, their extracts qualify as promising starting points for antimalarial drug discovery.

16.
Medicines (Basel) ; 2(3): 220-235, 2015 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-28930209

RESUMO

Mycoses caused by Candida and Cryptococcus species, associated with the advent of antifungal drug resistance have emerged as major health problems. Improved control measures and innovative therapies are needed. This paper describes results from the screening of bio-guided fractionated extracts alone and combinations of Terminalia catappa, Terminalia mantaly and Monodora tenuifolia harvested in Cameroon. Crude ethanolic, hydro-ethanolic and aqueous extracts and bio-guided fractions were screened for antifungal activity against isolates of C. albicans, C. glabrata, C. parapsilosis and Cr. neoformans and the reference strain C. albicans NR-29450. Minimal inhibitory concentrations (MIC) were determined using a broth micro dilution method according to the Clinical & Laboratory Standards Institute (CLSI). Time kill kinetics of extracts alone and in combination were also evaluated. Extracts from T. mantaly stem bark were the most active with the best MIC values ranging from 0.04 mg/mL to 0.16 mg/mL. Synergistic interactions were observed with combinations of sub-fractions from M. tenuifolia, T. mantaly and T. catappa. Combination of sub-fractions from M. tenuifolia and T. mantaly (C36/C12) showed synergistic interaction and fungicidal effect against four out of five tested yeasts. These results support further investigation of medicinal plant extracts alone and in combination as starting points for the development of alternative antifungal therapy.

17.
BMC Complement Altern Med ; 14: 125, 2014 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-24708588

RESUMO

BACKGROUND: Cancer has become a global public health problem and the search for new control measures is urgent. Investigation of plant products such as essential oils from Monodora myristica, Xylopia aethiopica and Xylopia parviflora might lead to new anticancer therapy. In this study, we have investigated the antineoplastic activity of essential oils from fruits of these plants growing in Chad and Cameroon. METHODS: The essential oils obtained by hydrodistillation of fruits of Monodora myristica, Xylopia aethiopica and Xylopia parviflora collected in Chad and Cameroon were analyzed by GC-FID and GC-MS and investigated for their antiproliferative activity against the breast cancer cell line (MCF7). RESULTS: Overall, monoterpenes were mostly found in the six essential oils. Oils from X. aethiopica and X. parviflora from Chad and Cameroon mainly contain ß-pinene at 24.6%, 28.2%, 35.7% and 32.9% respectively. Monodora myristica oils from both origins contain mainly α-phellandrene at 52.7% and 67.1% respectively. The plant origin did not significantly influence the chemical composition of oils. The six essential oils exerted cytotoxic activity against cancer (MCF-7) and normal cell lines (ARPE-19), with more pronounced effect on neoplastic cells in the majority of cases. The highest selectivity was obtained with the essential oils of X. parviflora from Chad and Cameroon (5.87 and 5.54) which were more cytotoxic against MCF-7 than against normal cell line (ARPE-19) with IC50 values of 0.155 µL/mL and 0.166 µL/mL respectively. CONCLUSIONS: Essential oils from fruits of Monodora myristica, Xylopia aethiopica and Xylopia parviflora have shown acceptable antineoplastic potency, and might be investigated further in this regard.


Assuntos
Annonaceae/química , Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Óleos Voláteis/uso terapêutico , Fitoterapia , Extratos Vegetais/uso terapêutico , Xylopia/química , Antineoplásicos Fitogênicos/análise , Antineoplásicos Fitogênicos/farmacologia , Compostos Bicíclicos com Pontes/análise , Compostos Bicíclicos com Pontes/farmacologia , Compostos Bicíclicos com Pontes/uso terapêutico , Camarões , Linhagem Celular , Chade , Frutas , Humanos , Células MCF-7 , Monoterpenos/análise , Monoterpenos/farmacologia , Monoterpenos/uso terapêutico , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia
18.
BMC Complement Altern Med ; 13: 266, 2013 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-24131916

RESUMO

BACKGROUND: Nauclea latifolia Smith, a shrub belonging to the family Rubiaceae is a very popular medicinal plant in Cameroon and neighboring countries where it is used to treat jaundice, yellow fever, rheumatism, abdominal pains, hepatitis, diarrhea, dysentery, hypertension, as well as diabetes. The ethno-medicinal use against yellow fever, jaundice and diarrhea prompted us to investigate on the antiviral activity of the root bark of N. latifolia. In this study, HSV-2 was chosen as a viral model because of its strong impact on HIV transmission and acquisition. METHODS: The crude extract under study was prepared by maceration of air-dried and powdered roots barks of N. latifolia in CH2Cl2/MeOH (50:50) mixture for 48 hours, then it was subjected to filtration and evaporation under vacuum. A phytochemical analysis of the crude extract was performed by High Performance Liquid Chromatography coupled with a photodiode array and mass spectrometry (HPLC-PDA-ESI-qMS). The anti-HSV-2 activity was assayed in vitro by plaque reduction and virus yield assays and the major mechanism of action was investigated by virucidal and time of addition assays. Data values were compared using the Extra sum of squares F test of program GraphPad PRISM 4. RESULTS: The main components detected in the extract belong to the class of indole alkaloids characteristic of Nauclea genus. Strictosamide, vincosamide and pumiloside were tentatively identified together with quinovic acid glycoside. N. latifolia crude extract inhibited both acyclovir sensitive and acyclovir resistant HSV-2 strains, with IC50 values of 5.38 µg/ml for the former and 7.17 µg/ml for the latter. The extract was found to be most active when added post-infection, with IC50 of 3.63 µg/ml. CONCLUSION: The results of this work partly justify the empirical use of N. latifolia in traditional medicine for the treatment of viral diseases. This extract could be a promising rough material for the development of a new and more effective modern anti-HSV-2 medication also active against acyclovir-resistant HSV-2 strains.


Assuntos
Antivirais/farmacologia , Herpesvirus Humano 2/efeitos dos fármacos , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Rubiaceae/química , Antivirais/química , Camarões , Medicina Tradicional , Extratos Vegetais/química
19.
BMC Complement Altern Med ; 13: 175, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23855679

RESUMO

BACKGROUND: Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycaemia generally associated with oxidative stress. The present study aims at evaluating the antioxidant and antidiabetic potential of methanol and hydroethanol extracts of the stem bark and leaves of Pricralima nitida and the Sonchus oleraceus whole plant respectively. METHODS: The in vitro antioxidant activity was assessed using 1,1-Diphenyl-2-picrilhydrazyl (DPPH) for free radical-scavenging properties of the extracts, and the Folin-Ciocalteu method in determining their phenol contents. The antidiabetic activity was tested in mice following streptozotocin diabetes induction, and selected oxidative stress markers (Malondialdehyde, Hydrogen peroxides and Catalase) were measured in order to evaluate the level of oxidative stress in treated animals. RESULTS: The in vitro antioxidant activity using DPPH showed IC50 ranging from 0.19 ± 0.08 to 1.00 ± 0.06 mg/mL. The highest activity was obtained with the hydroethanol extracts of S. oleraceus (0.19 mg/mL and P. nitida (0.24 mg/mL). Polyphenol contents ranged from 182.25 ± 16.76 to 684.62 ± 46.66 µg Eq Cat/g. The methanol extract of P. nitida showed the highest activity, followed by the hydroethanol extract of S. oleraceus (616.89 ± 19.20 µEq Cat/g). The hydroethanol extract of whole plants (150 mg/Kg) and methanol leave extract of P. nitida (300 mg/Kg) exhibited significant antidiabetic activities with 39.40% and 38.48% glycaemia reduction, respectively. The measurement of stress markers in plasma, liver and kidney after administration of both extracts showed significant reduction in MDA and hydrogen peroxide levels, coupled with a substantial increase in catalase activity. CONCLUSIONS: These findings suggest that S. oleraceus whole plant and P. nitida leaves possess both antidiabetic and antioxidant properties, and therefore could be used as starting point for the development of herbal medicines and/or source of new drug molecules against diabetes.


Assuntos
Antioxidantes/uso terapêutico , Apocynaceae/química , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Fitoterapia , Sonchus/química , África , Animais , Antioxidantes/farmacologia , Compostos de Bifenilo/metabolismo , Glicemia/metabolismo , Catalase/sangue , Diabetes Mellitus Experimental/sangue , Peróxido de Hidrogênio/sangue , Hiperglicemia/sangue , Hiperglicemia/tratamento farmacológico , Hipoglicemiantes/farmacologia , Masculino , Malondialdeído/sangue , Camundongos , Picratos/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Estruturas Vegetais , Polifenóis/farmacologia , Polifenóis/uso terapêutico
20.
J Ethnopharmacol ; 139(1): 171-80, 2012 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-22079831

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Malaria endemic countries have vital resources that are medicinal plants on which their traditional medicines depend. In some Cameroonian settings, in addition to the commonly used potions from plants like Alstonia boonei, Zanthoxylum macrophylla and Mangifera indica, other herbal species are being increasingly used to treat malaria. So, specialized traditional healers have developed alternative reasonably priced therapies, relying on the signs and/or symptoms of malaria. Within this framework, Annonaceae plants were found to be increasingly utilized and therefore, highlighting the need to document this traditional knowledge for better malaria control. MATERIALS AND METHODS: Interview approach was used to document indigenous knowledge, usage customs and practices of Annonaceae species in the treatment of malaria in four Cameroonian areas (Yaoundé and its surroundings, Ngoyang, Kon-Yambetta and Mbalmayo). RESULTS: A total of 19/30 users of plants accepted to share their experiences during a semi-structured survey. Twelve of the respondents were men and seven were women. Thirty recipes based on twenty-one plants were recorded. CONCLUSION: Annickia chlorantha was the only plant commonly found in the four study sites. Seven species of Annonaceae were found to be used to treat malaria, while 14 were used to treat symptoms that might be related to malaria.


Assuntos
Annonaceae , Antimaláricos/uso terapêutico , Conhecimentos, Atitudes e Prática em Saúde , Malária/tratamento farmacológico , Fitoterapia , Plantas Medicinais , Adulto , Idoso , Camarões , Etnofarmacologia , Feminino , Pessoal de Saúde , Humanos , Entrevistas como Assunto , Masculino , Medicina Tradicional Africana , Pessoa de Meia-Idade
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