In vitro antiplasmodial activity-directed investigation and UPLC–MS fingerprint of promising extracts and fractions from Terminalia ivorensis A. Chev. and Terminalia brownii Fresen.

Please read abstract in the article.The Grand Challenges Africa programme is supported by the African Academy of Sciences (AAS), Bill & Melinda Gates Foundation (BMGF), Medicines for Malaria Venture (MMV), and Drug Discovery and Development Centre of University of Cape Town (H3D).https://www.elsevier.com/locate/jethpharm2023-07-09hj2023Chemistr

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

Senegalin, a new phenylpropanoid and other secondary metabolites from the stem bark of Ekebergia senegalensis A. Juss. (Meliaceae).

Kemayou GPM, Happi GM, Ngandjui YAT, et al. Senegalin, a new phenylpropanoid and other secondary metabolites from the stem bark of Ekebergia senegalensis A. Juss. (Meliaceae). Natural product research. 2020:1-7.Senegalin (1), a new phenylpropanoid has been isolated from the stem bark of Ekebergia senegalensis A. Juss. along with twelve known secondary metabolites including coumarins 2-5, 4-hydroxy-3,5-methylbenzoic acid (6), pentacyclic triterpenoids 7-9, acyclic triterpenoids 10 and 11 and steroids 12 and 13, respectively. Their structures were elucidated with the help of spectroscopic techniques including 1D- and 2D-NMR. The antibacterial activity of the major compounds (2, 9-11) was evaluated on five bacterial strains. However, only compounds 2 and 11 showed a weak inhibition against Bacillus subtilis and Pseudomonas agarici. Furthermore, the chemotaxonomic significance of these compounds has also been elaborated

Antischistosomal Evaluation of Stem Bark's Extract and Chemical Constituents from Anonidium mannii against Schistosoma mansoni

Context Anonidium mannii (Annonaceae) has been traditionally used in Africa to treat stomach aches, schistosomiasis, and many other illnesses. However, few phytochemical study and no investigation on schistosomiasis have been conducted on this species. This neglected tropical disease, caused by a worm, comes second after malaria as the most devastating parasitical infection. Aim: The goal of this study was to evaluate the anti-Schistosoma mansoni activity of fractions and constituents from A. mannils stem bark and also to search efficient inhibitors of a recently discovered ectoenzyme of S. mansoni (S. mansoni nicotinamide adenine dinucleotide + catabolizing enzyme (SmNACED. Materials and Methods: The powdered stem bark of A. mannii was extracted with ethanol/distilled water (80:20). The extract was then subjected to a partial bioguided separation by chromatography means. The structures of compounds were elucidated using modern spectroscopic techniques. Furthermore, isolated and semisynthetic compounds were evaluated for their antischistosomal and cytotoxic activities. Results: Chemical investigation led to the isolation and identification of eight compounds, in the majority, obtained for the first time from this genus. In addition, acetylation reactions were carried out to afford a new semisynthetic derivative. Preliminary biological screening of the extracts and compounds showed very good activities from antiparasitic and enzymatic tests and also very good percentage of cell viability evaluation. Conclusion: Like praziquantel drug, gallic acid exhibited full anthelmintic activity at concentration of 100 mu M. On the other hand, piperolactam D showed important inhibition on SmNACE (IC50 10 mu M). Thus, standardization of bioactive fraction can help in improving traditional medicine. The optimization of those two compounds will enhance their selectivity/effectiveness and could be used as seed for the development of new remedies against schistosomiasis. Further, the study will be focus on other pathogens species of Schistosoma genus

Three phragmalin-type limonoids orthoesters and the structure of odoratone isolated from the bark of Entandrophragma candollei (Meliaceae)

Happi GM, Mouthe Kemayou GP, Stammler H-G, et al. Three phragmalin-type limonoids orthoesters and the structure of odoratone isolated from the bark of Entandrophragma candollei (Meliaceae). Phytochemistry. 2020;181: 112537.The phytochemical exploration of the Entandrophragma candollei stem bark extract led to the isolation and identification of twenty compounds including three undescribed phragmalin-class limonoids named encandollens C-E (1-3), the undescribed protolimonoid 5 together with sixteen known compounds. The structures of all the isolated compounds were determined by interpretation of their spectroscopic and spectrometric data including HRMS, 1D and 2D NMR analyses. The assignment of the absolute and relative stereochemistry of the undescribed compounds was achieved using SC-XRD analyses as well as NOESY experiments. The previously reported structure of odoratone (5a) was corrected as 23R,24S-dihydroxy-22S,25-epoxytirucall-7-en-3-one (5) based on its NMR and SC-XRD data. Prieurianin (4) exhibited high cytotoxic activity on KB3-1cell lines with an IC50 of 1.47muM compared to the reference griseofulvin (IC50=17-21muM). The results of the in silico docking of compound 4 supported and delivered further insights on its cytotoxicity. Copyright © 2020 Elsevier Ltd. All rights reserved

Manniindole, an indole derivative from the roots ofAnonidium manniiand combined antischistosomal and enzymatic activities

A new alkaloid, manniindole1, together with four known compounds: aristolactam AII2, aristolactam BII3, piperolactam D4and polycarpol5were isolated from the crude extract EtOH-H2O (8:2) of the roots ofAnonidium manniiby chromatographic separation. The structure elucidation was performed on the basis of a spectroscopic analysis (IR, HRESI MS, 1D and 2D NMR) as well as a comparison of their spectral data with those reported in the literature. For the first time, the crude extract and those isolated compounds were evaluated for their anti-schistosomal activity againstSchistosoma mansoniand for cytotoxicity activity against Huh7 and A549 cells. Furthermore, they were also testedin vitroon the recent characterizedSchistosoma mansoniNAD(+)catabolizing enzyme (SmNACE) for their impact on this enzyme which is localized on the outer surface of the adult parasite. Compound2displayed quite good worm killing capability, while4showed significant inhibition ofSmNACE

Structural analysis and molecular docking study of pachypodostyflavone: A potent anti-onchocerca

Mountessou BYG, Ngouonpe AW, Mbobda ASW, et al. Structural analysis and molecular docking study of pachypodostyflavone: A potent anti-onchocerca. Journal of Molecular Structure. 2023;1291: 136003.In order to get a better insight into the intermolecular interactions in the solid state of the naturally occurring flavone derivative, pachypodostyflavone, its single crystal X-ray diffraction was performed and analysed. Structural analysis revealed that the compound crystallises in the monoclinic space group P21/c with a = 23.910 (1), b = 13.256(1), c = 8.044(1) & ANGS;, & beta; = 94.96(1), Z = 4. An experimental and theoretical investigation of pachypodostyflavone is presented, combining the use of vibrational spectroscopies (IR, NMR and UV-visible) with density functional theory (DFT) that employs hybrid B3LYP exchange correlation functional with 6-311++G(d,p) as basis set. HOMO-LUMO, MEP, and NBO analysis was investigated and reactivity descriptors were calculated. Analysis of chemical reactivity indicates that the compound is more reactive in water, which is a good indicator for clinical preparations. Thermodynamic properties viz., heat capacity, entropy, and enthalpy change of title molecule at various temperatures are presented. Additionally, molecular docking results revealed that pachypodostyflavone structure strongly binds to the parasitic worm Onchocerca volvulus by relative binding affinity of -7.00 kcal mol-1

Potentiation effect of mallotojaponin B on chloramphenicol and mode of action of combinations against Methicillin-resistant Staphylococcus aureus.

Staphylococcus aureus, the causative agent of many infectious diseases has developed resistance to many antibiotics, even chloramphenicol which was the essential antibiotic recommended for the treatment of bacterial infection. Thus, other alternatives to fight against S. aureus infections are necessary; and combinatory therapy of antibiotics with natural compounds is one of the approaches. This study evaluated the activity of the combination of mallotojaponin B and chloramphenicol against Methicillin-resistant Staphylococcus aureus (MRSA). Antibacterial activities were evaluated by broth microdilution and the checkerboard methods. Modes of action as time-kill kinetic, Nucleotide leakage, inhibition and eradication of biofilm, and loss of salt tolerance were evaluated. Cytotoxicity was evaluated on Vero and Raw cell lines. Mallotojaponin B showed good activity against MRSA with a MIC value of 12.5 μg/mL. MRSA showed high resistance to chloramphenicol (MIC = 250 μg/mL). The combination produced a synergistic effect with a mean FICI of 0.393. This combination was bactericidal, inducing nucleotide leakage, inhibiting biofilm formation, and eradicating biofilm formed by MRSA. The synergic combination was non-cytotoxic to Vero and Raw cell lines. Thus, the combination of mallotojaponin B and chloramphenicol could be a potential alternative to design a new drug against MRSA infections