Antifungal activity and acute toxicity of stem bark extracts of Drypetes Gossweileri S. Moore-Euphorbiaceae from Cameroon

Drypetes gossweilleri S. Moore is a plant used in traditional medicine in Cameroon. The antifungal properties of its stem-bark crude extract and fractions DG1, DG2, DG3, DG4, DG5, DG6, DG7, DG8 and DG9 were assayed by agar and broth dilution methods on solid and liquid media against C. Krusei, C. albicans, C. glabrata, T. mentagerophytes, M. langeroinii, M. gypeum, M. audouini, T. rubrum, T. soudanense, T. terrestre, A. flavus and A. niger. The results revealed a substantial antifungal effect with minimal inhibitory concentrations ranging respectively from 24.11μg/ml to 1562μg/ml for yeasts and from 3125μg/ml to 12500μg/ml for filamentous fungi. Among the fractions, fraction DG4 exerted the highest antifungal activity. Moreover, no toxic effect was noticed in male and female albinos Wistar rats treated per os with the crude stem bark’s extract of Drypetes gossweileri at a dose up to 12g/kg of body weight. The phytochemical screening of the crude extract and fractions showed the presence of alkaloids, phenols, flavonoids, saponins, anthocyanines, anthraquinones, sterols, lipids and essential oils. Therefore, Drypetes gossweileri may be safe as phytomedecine for the treatment of fungal infections.Key words: Antifungal activity, Drypetes gossweileri, acute toxicity

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

Diterpenoids with thioredoxin reductase inhibitory activities from Jatropha multifida.

Chemical investigation of the Jatropha multifida has led to the isolation of nine diterpenoids (1-9), including a new jatromulone A, four podocarpane diterpenoids (2-5), two lathyrane-type diterpenoids (6 and 7) and two dinorditerpenoids (8 and 9). Their structures were elucidated by spectroscopic analysis, and the absolute configurations of 1 were determined by CD analysis. All of the diterpenoids were screened for inhibitory activity against thioredoxin reductase (TrxR), which is a potential target for cancer chemotherapy with redox balance and antioxidant functions. Compounds 6 and 7 exhibited stronger activity (IC50: 23.4 and 10.6 μM, respectively) than the positive control, curcumin (IC50 = 25.0 μM). Compounds 2-9 were isolated from J. multifida for the first time

Methyl 5,7-dihydr­oxy-2,2,9-trimethyl-6,11-dioxo-6,11-dihydro-2H-anthra[2,3-b]pyran-8-carboxyl­ate

The title compound, C22H18O7, also known as laurentiquinone B, is a new anthraquinone which was isolated from Vismia laurentii, a Cameroonian medicinal plant. The asymmetric unit contains two independent mol­ecules. Each of them contains four fused rings, three of which are coplanar and typical of anthracene, while the heterocyclic rings adopt envelope conformations. Intra­molecular O—H⋯O hydrogen bonds result in the formation of two planar rings, which are also almost coplanar with the adjacent rings. In the crystal structure, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules and a π–π contact is also present [centroid-centroid distance = 3.967 (3) Å]

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

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 and cytotoxic activities of flavonoids and arylbenzofuran derivatives from Morus mesozygia

Morus mesozygia Stapf (Moraceae) is a plant found in many regions and used in treating many diseases including malaria and fever. Fractionation of the methanolic extract of its stem bark, using various chromatographic methods has led to the isolation and identification of 3 flavonoids: artocarpesin, artochamin C and kushenol E. And 4 arylbenzofuran derivatives: moracin M, moracin C, moracin L and mulberofuran F. The methanolic extract and the seven isolated compounds were tested for antiplasmodial activity against the chloroquine-resistant FcB1 Plasmodium falciparum strain and cytotoxicity on MCF-7 human breast cancer cells. Relating to the antiplasmodial activity, it was found that all compounds were active against the FcB1 strain of Plasmodium with artocarpesin, koushenol E and mulberrofuran F showing particular potency (with the median inhibitory concentrations IC50 = 2.5-2.6 μg/ml). Cytotoxicity tests performed on MCF-7 cells revealed all the IC50 varying from &lt;1.0 to 5.0 ± 0.6 μg/mL. A structure – activity relationship is discussed