المؤلفون: Christine C. Waleguele, Brice M. Mba’ning, Angelbert F. Awantu, Jean J. K. Bankeu, Yannick S. F. Fongang, Augustin S. Ngouela, Etienne Tsamo, Norbert Sewald, Bruno N. Lenta, Rui W. M. Krause

المصدر: Molecules, Vol 25, Iss 12, p 2862 (2020)

مصطلحات موضوعية: Lauraceae, Beilschmiedia obscura, Beilschmiedia louisii, endiandric acid, antitrypanosomal activity, Organic chemistry, QD241-441

الوصف: The MeOH/CH2Cl2 (1:1) extracts of the roots and leaves of Beilschmiedia louisii and B. obscura showed potent antitrypanosomal activity during preliminary screening on Trypanosoma brucei brucei. Phytochemical investigation of these extracts led to the isolation of a mixture of two new endiandric acid derivatives beilschmiedol B (1) and beilschmiedol C (2), and one new phenylalkene obscurene A (3) together with twelve known compounds (4–15). In addition, four new derivatives (11a–11d) were synthesized from compound 11. Their structures were elucidated based on their NMR and MS data. Compounds 5, 6, and 7 were isolated for the first time from the Beilschmiedia genus. Additionally, the NMR data of compound 4 are given here for the first time. The isolates were evaluated for their antitrypanosomal and antimalarial activities against Tb brucei and the Plasmodium falciparum chloroquine-resistant strain Pf3D7 in vitro, respectively. From the tested compounds, the mixture of new compounds 1 and 2 exhibited the most potent antitrypanosomal activity in vitro with IC50 value of 4.91 μM.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/1420-3049/25/12/2862Test; https://doaj.org/toc/1420-3049Test

الوصول الحر: https://doaj.org/article/d9edaaa9079443f383695e7ea458bce7Test

المؤلفون: Joël E. T. Ateba, Rufin M. K. Toghueo, Angelbert F. Awantu, Brice M. Mba’ning, Sebastian Gohlke, Dinkar Sahal, Edson Rodrigues-Filho, Etienne Tsamo, Fabrice F. Boyom, Norbert Sewald, Bruno N. Lenta

المصدر: Journal of Fungi, Vol 4, Iss 2, p 70 (2018)

مصطلحات موضوعية: malaria, chloroquine-resistant Plasmodium falciparum, Symphonia globulifera, endophytic fungi, antiplasmodial IC50, selectivity index, Biology (General), QH301-705.5

الوصف: There is continuing need for new and improved drugs to tackle malaria, which remains a major public health problem, especially in tropical and subtropical regions of the world. Natural products represent credible sources of new antiplasmodial agents for antimalarial drug development. Endophytes that widely colonize healthy tissues of plants have been shown to synthesize a great variety of secondary metabolites that might possess antiplasmodial benefits. The present study was carried out to evaluate the antiplasmodial potential of extracts from endophytic fungi isolated from Symphonia globulifera against a chloroquine-resistant strain of Plasmodium falciparum (PfINDO). Sixty-one fungal isolates with infection frequency of 67.77% were obtained from the bark of S. globulifera. Twelve selected isolates were classified into six different genera including Fusarium, Paecilomyces, Penicillium, Aspergillus, Mucor, and Bipolaris. Extracts from the 12 isolates were tested against PfINDO, and nine showed good activity (IC50 < 10 μg·mL−1) with three fungi including Paecilomyces lilacinus (IC50 = 0.44 μg·mL−1), Penicillium janthinellum (IC50 = 0.2 μg·mL−1), and Paecilomyces sp. (IC50 = 0.55 μg·mL−1) showing the highest promise. These three isolates were found to be less cytotoxic against the HEK293T cell line with selectivity indices ranging from 24.52 to 70.56. Results from this study indicate that endophytic fungi from Symphonia globulifera are promising sources of hit compounds that might be further investigated as novel drugs against malaria. The chemical investigation of active extracts is ongoing.

وصف الملف: electronic resource

العلاقة: http://www.mdpi.com/2309-608X/4/2/70Test; https://doaj.org/toc/2309-608XTest

الوصول الحر: https://doaj.org/article/997e6f685e2c4050892bdf144f966554Test

المؤلفون: Norbert Sewald, Etienne Tsamo, Muhammad Iqbal Choudhary, Qamar Naz, Marcel Kaiser, Joseph Ngoupayo, Krishna Prasad Devkota, Bernard Weniger, Catherine Vonthron-Sénécheau, Bruno Ndjakou Lenta

المصدر: Molecules, Vol 12, Iss 8, Pp 1548-1557 (2007)

مصطلحات موضوعية: Allanblackia monticola, Symphonia globulifera, Phenolic compounds, Leishmanicidal, Anticholinesterase, Organic chemistry, QD241-441

الوصف: In a preliminary antiprotozoal screening of several Clusiaceae species, the methanolic extracts of Allanblackia monticola and Symphonia globulifera showed high in vitro leishmanicidal activity. Further bioguided phytochemical investigation led to the isolation of four benzophenones: guttiferone A (1), garcinol (2), cambogin (3) and guttiferone F (4), along with three xanthones: allanxanthone A (5), xanthone V1 (6) and globulixanthone C (7) as active constituents. Compounds 1 and 6 were isolated from S. globulifera leaves, while compounds 2-5 were obtained from A. monticola fruits. Guttiferone A (1) and F (4) showed particulary strong leishmanicidal activity in vitro, with IC50 values (0.2 μM and 0.16 μM, respectively) comparable to that of the reference compound, miltefosine (0.46 μM). Although the leishmanicidal activity is promising, the cytotoxicity profile of these compounds prevent at this state further in vivo biological evaluation. In addition, all the isolated compounds were tested in vitro for their anticholinesterase properties. The four benzophenones showed potent anticholinesterase properties towards acetylcholinesterase (AChE) and butylcholinesterase (AChE). For AChE, the IC50 value (0.66 μM) of garcinol (2) was almost equal to that of the reference compound galanthamine (0.50 μM). Furthermore, guttiferone A (1) and guttiferone F (4) (IC50 = 2.77 and 3.50 μM, respectively) were more active than galanthamine (IC50 = 8.5) against BChE.

وصف الملف: electronic resource

العلاقة: http://www.mdpi.com/1420-3049/12/8/1548Test/; https://doaj.org/toc/1420-3049Test

الوصول الحر: https://doaj.org/article/f70f9a2db4e84c8b8ad92d80fbebc235Test

المؤلفون: Silvere Ngouela, Guy Feuya, Jean C. Tchouankeu, Gaston Achoundong, Raymond B.T. Zambou, Etienne Tsamo, Joseph D. Connolly

المصدر: Bulletin of the Chemical Society of Ethiopia, Vol 18, Iss 2, Pp 221-224 (2004)

مصطلحات موضوعية: Meiocarpidium lepidotum, Annonaceae, lignan, Chemistry, QD1-999

الوصف: A new lignan, meiocarpin, and the known compounds, sitosterol and polycarpol, have been isolated from the stem bark of Meiocarpidium lepidotum, Annonaceae. The structure of the new compound was elucidated on the basis of its spectroscopic data.

وصف الملف: electronic resource

العلاقة: http://www.ajol.info/index.php/bcse/article/view/61453Test; https://doaj.org/toc/1011-3924Test; https://doaj.org/toc/1726-801XTest

الوصول الحر: https://doaj.org/article/737594c860354f60b40d81b2fbe2db37Test

المؤلفون: Bruno N. Lenta, Silvere Ngouela, Diderot T. Noungoue, Etienne Tsamo, Joseph D. Connolly

المصدر: Bulletin of the Chemical Society of Ethiopia, Vol 18, Iss 2, Pp 175-180 (2004)

مصطلحات موضوعية: Symphonia globulifera, Seeds, Xanthone, Antimicrobial activity, Chemistry, QD1-999

الوصف: A new prenylated pyranoxanthone, symphonin (1), 2-(3,3-dimethylallyl)-1,5- dihydroxy-6,7-dimethoxy-2”,2”-dimethylpyrano (5”,6”:3,4) xanthone, the known compounds guttiferone A, oleanolic acid and sitosterol were isolated from the methanol extract of the seeds of Symphonia globulifera (Guttiferae). The structural elucidation of the new compound was based mainly on spectroscopic analyses. The new xanthone showed antimicrobial activity against Staphylococcus aureus, Streptococcus feacalis, Klebsiella pneumonia and Escherichia coli.

وصف الملف: electronic resource

العلاقة: http://www.ajol.info/index.php/bcse/article/view/61439Test; https://doaj.org/toc/1011-3924Test; https://doaj.org/toc/1726-801XTest

الوصول الحر: https://doaj.org/article/e6ef12b658a64590ae1f28363bec976bTest

المؤلفون: Etienne Tsamo, Diderot T. Noungoue, Joseph Ngoupayo, Silvère Ngouela, Joseph D. Connolly

المصدر: Bulletin of the Chemical Society of Ethiopia, Vol 17, Iss 2, Pp 181-184 (2003)

مصطلحات موضوعية: Gossweilone, Podocarpane diterpenoid, Drypetes gossweileri, Euphorbiaceae, Chemistry, QD1-999

الوصف: A new podocarpane diterpenoid, named gossweilone (1), has been isolated from the stem bark of Drypetes gossweileri, along with two known friedelane triterpenoids. The structure of the new compound was elucidated using spectroscopic methods.

وصف الملف: electronic resource

العلاقة: http://www.ajol.info/index.php/bcse/article/view/61672Test; https://doaj.org/toc/1011-3924Test; https://doaj.org/toc/1726-801XTest

الوصول الحر: https://doaj.org/article/c5a47ad294c94195b3d920e2d897f757Test

المؤلفون: Marthe Aimée Tchuente Tchuenmogne, Thierry Ngouana Kammalac, Sebastian Gohlke, Rufin Marie Toghueo Kouipou, Abdulselam Aslan, Muslum Kuzu, Veysel Comakli, Ramazan Demirdag, Silvère Augustin Ngouela, Etienne Tsamo, Norbert Sewald, Bruno Ndjakou Lenta, Fabrice Fekam Boyom

المصدر: Medicines, Vol 4, Iss 1, p 6 (2017)

مصطلحات موضوعية: Terminalia mantaly, Combretaceae, anti-yeast, enzyme inhibitors, Medicine

الوصف: 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-β-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)

وصف الملف: electronic resource

العلاقة: http://www.mdpi.com/2305-6320/4/1/6Test; https://doaj.org/toc/2305-6320Test

الوصول الحر: https://doaj.org/article/6b77cb5b1ca947ce89c8ba189d2fa88fTest

المؤلفون: Anar Sahib Gojayev, Jean Jules Kezetas Bankeu, Angelbert Fusi Awantu, Eric René Sieliatchom Nkanwen, Muhammad Shaiq Ali, Bruno Ndjakou Lenta, Akif Alakbar Guliyev, Didérot Tchamo Noungoué, Silvère Augustin Ngouela, Etienne Tsamo

المصدر: Bangladesh Journal of Pharmacology, Vol 8, Iss 1 (2013)

مصطلحات موضوعية: Chythrantus claneianus, rheumatism, xanthine oxidase inhibitor, Therapeutics. Pharmacology, RM1-950

الوصف: Phytochemical investigation of the stem bark and the trunk of Chythrantus claneianus led to the isolation of six known compounds named β-sitosterol (1), umbelliferone (2), scopoletin (3), benjaminamide (4), β-sitosterol-3-O-β-D-glucopyranoside (5) and panconoside B (6). All these compounds were isolated for the first time from this plant species. The chemical structures of isolates were elucidated on the basis of 1 and 2 D-NMR spectra and other spectroscopic techniques including UV–vis, FT-IR, HR-ESIMS and HR-FABMS. The isolates were tested in vitro for their inhibitory properties towards xanthine oxidase enzyme. Compounds 2, 3 and 6 showed weak inhibitory activities on the enzyme with IC50 values ranging from 307 µM for compound 6 to 475 µM for compound 3, while the extract and compounds 1, 4 and 5 showed extremely weak activities with inhibition percentage less than 50%.

وصف الملف: electronic resource

العلاقة: https://www.banglajol.info/index.php/BJP/article/view/13485Test; https://doaj.org/toc/1991-0088Test

الوصول الحر: https://doaj.org/article/cac1997a64364844abf74f8df5037bf3Test

المؤلفون: Erik Donfack Vouffo (10806893), Clovis Douanla-Meli (10806896), Angelbert Fusi Awantu (10806899), Bruno Ndjakou Lenta (2329486), Sylvère Ngouela (10806902), Etienne Tsamo (2188750), Hartmut Laatsch (784500)

مصطلحات موضوعية: Pharmacology and Pharmaceutical Sciences not elsewhere classified, Cercophora samala, endophytic fungus, mitrafungidione, maristachones, DFT calculations

الوصف: Supplemental material, Online Supplementary file 1, for New Metabolites From the Endophytic Fungus Cercophora samala Associated With Mitragyna inermis by Erik Donfack Vouffo, Clovis Douanla-Meli, Angelbert Fusi Awantu, Bruno Ndjakou Lenta, Sylvère Ngouela, Etienne Tsamo and Hartmut Laatsch in Natural Product Communications

العلاقة: https://figshare.com/articles/journal_contribution/Online_Supplementary_file_1_-_Supplemental_material_for_New_Metabolites_From_the_Endophytic_Fungus_i_Cercophora_samala_i_Associated_With_i_Mitragyna_inermis_i_/14602841Test

الإتاحة: https://doi.org/10.25384/sage.14602841.v1Test

المؤلفون: Marthe Aimée Tchuente Tchuenmogne, Rui W. M. Krause, Etienne Tsamo, Augustin S. Ngouela, Yannick Stéphane Fotsing Fongang, Bruno Ndjakou Lenta, Norbert Sewald, Jean Jules Kezetas Bankeu, Christine Claire Waleguele, Jules Ngatchou

المصدر: Zeitschrift für Naturforschung C. 77:125-131

مصطلحات موضوعية: Lignan, Persea, biology, Traditional medicine, Chemistry, Fatty alcohol, Lauraceae, biology.organism_classification, General Biochemistry, Genetics and Molecular Biology, HeLa, chemistry.chemical_compound, Scopoletin, Lactate dehydrogenase, Cytotoxicity

الوصف: The antiplasmodium assay-guided investigation of the roots, stem bark, and leaves of Persea americana Mill. led to the isolation of a new fatty alcohol, perseatriol (1), along with six known compounds (2–7). Their structures were elucidated based on the analysis of their NMR and MS data. All crude extracts and fractions exhibited good antiplasmodial activity on Plasmoduim falciparum 3D7 with IC50 values ranging from 0.76 to 10.5 μg/mL; they also displayed cytotoxicity against HeLa cells with low selectivity indexes (SIs). A preliminary Plasmodium lactate dehydrogenase (pLDH) assay was also performed on the isolated compounds. 9,9′-Di-O-feruloyl-5,5′-dimethoxysecoisolariciresinol (4) turned out to be non-toxic and displayed the best activities on P. falciparum with an IC50 value of 0.05 μM, comparable to the reference drug chloroquine with an IC50 value of 0.03 μM. Furthermore, besides compound 4, this work reports the first isolation of lutein (2) and scopoletin (3) from P. americana. The crude extracts of roots, stem bark, and leaves of P. americana, their fractions and compounds completely suppressed the growth of P. falciparum. The observed activity supports the use of P. americana in folk medicine for the treatment of malaria.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::b2fd964a4f0beec736ffde9875a8d61aTest
https://doi.org/10.1515/znc-2021-0182Test