Gossweilone: A new podocarpane derivative from the stem bark of Drypetes gossweileri (Euphorbiaceae)

 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. KEY WORDS: Gossweilone, Podocarpane diterpenoid, Drypetes gossweileri, Euphorbiaceae  Bull. Chem. Soc. Ethiop. 2003, 17(2), 181-184

Symphonin: A new prenylated pyranoxanthone With antimicrobial activity from the seeds of Symphonia globulifera (guttiferae)

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. KEY WORDS: Symphonia globulifera, Seeds, Xanthone, Antimicrobial activity  Bull. Chem. Soc. Ethiop. 2004, 18(2), 175-180

Meiocarpin: A novel lignan from the stem bark of Meiocarpidium lepidotum (Annonaceae)

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. KEY WORDS: Meiocarpidium lepidotum, Annonaceae, lignan  Bull. Chem. Soc. Ethiop. 2004, 18(2), 221-224

Antiparasitic Constituents of Beilschmiedia louisii and Beilschmiedia obscura and Some Semisynthetic Derivatives (Lauraceae)

Waleguele CC, Mba’ning BM, Awantu AF, et al. Antiparasitic Constituents of Beilschmiedia louisii and Beilschmiedia obscura and Some Semisynthetic Derivatives (Lauraceae). Molecules. 2020;25(12): 2862.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

Antiplasmodial Properties and Cytotoxicity of Endophytic Fungi from Symphonia globulifera (Clusiaceae)

Ateba JET, Toghueo RMK, Awantu AF, et al. Antiplasmodial Properties and Cytotoxicity of Endophytic Fungi from Symphonia globulifera (Clusiaceae). JOURNAL OF FUNGI. 2018;4(2): UNSP 70.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 mu g.mL(-1)) with three fungi including Paecilomyces lilacinus (IC50 = 0.44 mu g.mL(-1)), Penicillium janthinellum (IC50 = 0.2 mu g.mL(-1)), and Paecilomyces sp. (IC50 = 0.55 mu g.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

Compounds from <em>Terminalia mantaly</em> L. (Combretaceae) Stem Bark Exhibit Potent Inhibition against some Pathogenic Yeasts and Enzymes of Metabolic Significance<strong></strong>

Tchuenmogne MAT, Ngouana TK, Gohlke S, et al. Compounds from &lt;em&gt;Terminalia mantaly&lt;/em&gt; L. (Combretaceae) Stem Bark Exhibit Potent Inhibition against some Pathogenic Yeasts and Enzymes of Metabolic Significance&lt;strong&gt;&lt;/strong&gt;. Preprints. 2016.The chemical investigation of the anti-yeast methanol extract from the stem bark of Terminalia mantaly led to the isolation of seven compounds: 3-O-methyl-4-O-&amp;alpha;-rhamnopyranoside ellagic acid (1), 3-O-mehylellagic acid (2), arjungenin or 2,3,19,23-tetrahydroxyolean-12-en-28-o&amp;iuml;c acid (3), arjunglucoside or 2,3,19,23-tetrahydroxyolean-12-en-28-o&amp;iuml;c acid glucopyranoside (4), 2&amp;alpha;,3&amp;alpha;,24-trihydroxyolean-11,13(18)-dien-28-o&amp;iuml;c acid (5), stigmasterol (6), stigmasterol 3-O-&amp;beta;-D-glucopyranoside (7). Their structures were established by means of spectroscopic analysis and comparison with published data. Compounds 1-5 were tested in vitro for activity against three pathogenic yeast isolates, Candida albicans, Candida parapsilosis and Candida krusei. The activity of compounds 1, 2 and 4 were comparable to that of the reference compound fluconazole (MIC values below 32 &amp;micro;g/ml) against the three tested yeast isolates. They were also tested for inhibitory properties against four enzymes of metabolic significance: Glucose-6-Phosphate Deshydrogenase (G6PD), human erythrocyte Carbonic anhydrase I and II (hCA I and hCA II), Glutathione S-transferase (GST). Compound 4 showed highly potent inhibitory property against the four tested enzymes with overall IC50 values below 4 &amp;micro;M and inhibitory constant (Ki) &amp;lt;3 &amp;micro;M.</jats:p

Sapelenin D, a New Acyclic Triterpenoid from the Stem Bark of Entandrophragma cylindricum

International audienceA novel acyclic triterpenoid, sapelenin D (1) was isolated from the stem bark of Entandrophragma cylindricum. Its full structure including absolute configuration was determined from spectroscopic data and by chemical transformation

Antimalarial Activity in Crude Extracts of Some Cameroonian Medicinal Plants

Fifteen crude extracts from the stem bark and seeds of four medicinal plants, viz: Entandrophragma angolense, Picralima nitida, Schumanniophyton magnificum and Thomandersia hensii were tested in vitro for their antimalarial activity against the chloroquine-resistant Plasmodium falciparum W2 strain. The results showed that the extracts of these plants possessed some antimalarial activity, the methanol extract of Picralima nitida demonstrating the highest activity in vitro. Further isolation and identification of some active compounds from these plants will justify their common use in traditional medicine for the treatment of malaria or fever in Cameroon

The Antiplasmodial Agents of the Stem Bark of Entandrophragma Angolense (Meliaceae)

In the search of active principles from the stem bark of Entandrophragma angolense, we submitted the compounds isolated from the dichloromethane - methanol (1:1) extract of the stem bark to antimalarial test against chloroquine resistant strain W2 of Plasmodium falciparum malaria parasite. Only 7α-obacunyl acetate and a cycloartane derivative exhibited a good activity, with IC50s of 2 and 5.4 µg/ml respectively. Other compounds were moderately active