Joséphine NGO-MBING

Joséphine NGO-MBING · UY1 Research Hub

2025Article de revue

Compounds isolated from Rhabdophyllum arnoldianum: promising new molecules for cancer treatment through their inhibitory properties on tyrosine kinases and dihydrofolate reductase, revealed by molecular docking

Mamoudou Hamadou, Gaétan Bayiha Ba Njock, Albert Fouda Atangana, Mc Jésus Kinyok, Jairus Olumasai Nandwa, Marius Balemaken Missi et 5 autre(s)

Current Proteomics

Resistance to current anticancer therapies drives the demand for novel, multitarget agents with improved safety. We screened flavonoid-derived phytochemicals isolated from Rhabdophyllum arnoldianum for inhibition of two cancer-relevant enzymes, tyrosine kinase (TK, PDB 1IRK) and dihydrofolate reductase (DHFR, PDB 1DYR). After retrieval from PubChem, the ligands were energy-minimised (MMFF94) and docked using two independent pipelines: (i) a stand-alone AutoDock Vina (v1.5.7) run and (ii) an autonomous PyRx (v0.8) workflow that also employs the Vina scoring function but generates its own grid and ligand-pre-processing. The two campaigns are highly concordant (Pearson r = 0.9759 for TK and r = 0.9816 for DHFR), confirming the robustness of the predicted binding affinities. A stringent consensus filter, requiring a compound to rank within the top 5 % of binding energies for both targets and in both pipelines, identified three reliable multitarget hits: 6″-α-Rhamnopyranosyl-7-O-methylvitexin ( 2 ), Rhusflavone ( 10 ), and Amentoflavone ( 11 ). All three display predicted free-energy values ≤ –8.3 kcal.mol⁻¹ for TK and ≤ –9.4 kcal.mol⁻¹ for DHFR, with virtually identical binding poses (RMSD ≤ 1.2 Å) across the two docking engines. Detailed inspection of the complexes reveals conserved interactions, hydrogen bonds to Lys-212 (TK) or Asp-27 (DHFR), π-π stacking with Phe-345 (TK) or Arg-70 (DHFR), and extensive hydrophobic contacts that occupy the ATP- and folate-binding pockets. In silico ADMET profiling indicates moderate oral bioavailability, acceptable intestinal absorption, low blood-brain-barrier permeation, and no overt cardiotoxic or hepatotoxic alerts, although Amentoflavone may inhibit CYP2D6. The cross-validated docking workflow thus provides a high-confidence shortlist of natural-product-derived, dual-TK/DHFR inhibitors, illustrating how tandem computational pipelines can accelerate the discovery of multitarget anticancer leads from medicinal plants.

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2025Article de revue

Two new aggreceride derivatives and other chemical constituents from the stems of Tarenna conferta Benth and their potential antileishmanial activity against Leishmania donovani promastigotes: Insight from molecular docking analysis

Raïssa Carelle Dzukoug, Angélique Nicolas Messi, Rostanie Dongmo Zeukang, Susan L. Bonnet, Anke Wilhelm, Dénis-Grégoire Téné et 9 autre(s)

Biochemical Systematics and Ecology

Tarenna conferta Benth is traditionally used to treat fever, headaches, parasitic and skin diseases. The aim of this study was to identify potential antileishmanial bioactive compounds from T. conferta and in silico studies against target receptors (2JK6 and 2W0H). The performance of successive chromatographic techniques followed by characterization using NMR (1D and 2D) as well as HR-ESIMS analyses, of methylene choride fraction of the stems of T. conferta , led to the identification of two unprecedented derivatives i.e. a new derivative of a dicarboxylic acid ( 1 ) and a new hydroxy ester derivative ( 2 ), with seven known compounds 3 , 4 , 5 , 6 , 7 , 8 and 9 . Compounds 1, 3 and 4 displayed highly potent antileishmanial activity against Leishmania donovani promastigotes with IC 50 values of 3.586 ± 0.554 μg/mL, 0.154 ± 0.8123 μg/mL and 0.789 ± 0.105 μg/mL respectively, compared to amphotericine B (IC 50 = 0.198 ± 0.704 μM), used as positive control. However crude extract exhibited significant antileishmanial activity against L. donovani (MHOM/SD/62/1S) promastigotes (IC 50 56.860 ± 1.755 μg/mL) and showed no cytotoxicity on RAW 264.7 macrophage cells. The molecular docking provides a captivating glimpse into the intricate interactions between compounds 1 , 2 , 3 , and 4 and the target receptors (2JK6 and 2W0H). The results revealed that, compounds 1 , 3 , and 4 consistently displayed strong binding affinities and hydrogen bond interactions, showcasing their potential for effective therapeutic interventions. Compounds 2 and 3 exhibit moderate binding affinities with essential amino acids. In terms of potential drug development, compound 4 emerges as a standout candidate due to its exceptionally high binding affinities and specific interactions. • The phytochemistry of stems extract of Tarenna conferta afforded nine constituents. • T rans -docosanylferulate, ursolic acid, triacontan-1-ol, D-mannitol, inositol, oleanolic acid, daucosterol, Tarennaride and 18-hydroxyoctadecanyl heptadecanoate. • Compounds active against Leishmania donovani promastigotes and amastigotes forms. • Molecular docking studies support antileishmanial potential of the active compounds.

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2024Article de revueAccès ouvert

Rhizomatoflavonoid D and Other Flavonoids from the Twigs of Ochna Rhizomatosa as a Potential Inhibitor of HIV-1

Angélique Nicolas Messi, Bienvenu Tsakem, Mirabel Akongwi, Olusola Bodede, Phanankosi Moyo, Roger Moïse Mbanga Baleba et 9 autre(s)

Chemistry Africa

Abstract Currently, HIV morbidity and mortality in sub-Saharan Africa remain a huge concern and awaiting interventions. Even though the combination antiretroviral therapy (cART) has recorded significant success, drug resistance and limited access to available therapeutics are major factors responsible for the low impact of cART in several African communities. Herein, as part of our continuous effort on the investigation of bioactive metabolites of Ochna rhizomatosa , we report the isolation of a new flavonoid; Rhizomatoflavonoid D ( 1 ), alongside with four known ones ( 2 – 5 ). The structures of these compounds were elucidated by using spectroscopic techniques ( 1 H NMR, 13 C NMR, HSQC, HMBC, 1 H- 1 H COSY, and ROESY) and mass spectrometry. The antiviral activity of the resulting compounds was assessed using deCIPhR assay run in parallel with the Alamar Blue based cytotoxicity assay. This assay revealed a moderate activity for compound 4 (72% inhibition at 2.5 µg/mL) while compound 1 had minimal activity (36% inhibition at 2.5 µg/mL). The prominent inhibitory effect on HIV-1 was showed by compound 4 (IC 50 = 3.1 µM). Unfortunately, compound 4 proved to be non-selective as it demonstrated also a CC 50 = 5.2 µg/mL (Selectivity index of 1.7). The prominent inhibitory effect on HIV-1 showed by compound 4 (IC 50 = 3.1 µM) could be due the presence of a methoxy group at C-7, since this group enhances the lipophilicity of biflavonoids, thereby improving its incorporation into cells.

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2022Article de revueAccès ouvert

In Vitro and In Silico Potential Inhibitory Effects of New Biflavonoids from Ochna rhizomatosa on HIV-1 Integrase and Plasmodium falciparum

Angélique Nicolas Messi, Susan L. Bonnet, Brice Ayissi Owona, Anke Wilhelm, Eutrophe Le Doux Kamto, Joseph Thierry Ndongo et 7 autre(s)

Pharmaceutics

The aim of this study was to identify bioactive secondary metabolites from Ochna rhizomatosa with potential inhibitory effects against HIV and Plasmodium falciparum. A phytochemical study of O. rhizomatosa root barks resulted in the identification of three new biflavonoids (1–3), along with four known ones (4–7). Compound 7 (Gerontoisoflavone A) was a single flavonoid present in the rootbark of the plant and was used as a reference. Compound 1 (IC50 = 0.047 µM) was the only one with a noteworthy inhibitory effect against HIV-1 integrase in vitro. Chicoric acid (IC50 = 0.006 µM), a pure competitive inhibitor of HIV-1 integrase, was used as control. Compound 2 exhibited the highest antiplasmodial activity (IC50 = 4.60 µM) against the chloroquine-sensitive strain of Plasmodium falciparum NF54. Computational molecular docking revealed that compounds 1 and 2 had the highest binding score (−121.8 and −131.88 Kcal/mol, respectively) in comparison to chicoric acid and Dolutegravir (−116 and −100 Kcal/mol, respectively), towards integrase receptor (PDB:3LPT). As far as Plasmodium-6 cysteine s48/45 domain inhibition is concerned, compounds 1 and 2 showed the highest binding scores in comparison to chloroquine, urging the analysis of these compounds in vivo for disease treatment. These results confirm the potential inhibitory effect of compounds 1 and 2 for HIV and malaria treatment. Therefore, our future investigation to find inhibitors of these receptors in vivo could be an effective strategy for developing new drugs.

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2020PrépublicationAccès ouvert

Density Functional Theory of a New Derivative of Allantoin with Antiplasmodial Properties, Antimycobacterial Activities of Essential Oil from Cordia Batesii WERNHAM (Boraginaceae)

Eric Robert Tiam, Dominique Ngono Bikobo, Ibrahim Mbouombouo Ndassa, Norbert Mbabi Nyemeck, Auguste Abouem À Zintchem, Lawrence Ayong et 4 autre(s)

Research Square

Abstract Background: some chemical and pharmacological investigations were performed on the EtOAc and/or CH 2 Cl 2 extracts of the stems of Cordia batesii (Boraginaeae); one of its components was subjected to some quantum calculations to get improvement in the understanding of its 13 C–NMR and UV properties along with geometric, electronic, thermodynamic data and reactivity descriptors. Results: a new allantoin ( 1 ) derivative named batesiin ( 2 ) was characterized from the EtOAc extract; thirteen known compounds including allantoin ( 1 ) were either isolated or identified by means of MS, NMR, LC–MS and GC–MS. GC–MS was applied on a fraction of essential oil which was composed of a mixture of fatty acids ( 9 – 14 ). Density functional theory (DFT) calculations were applied on batesiin ( 2 ). Data were simulated using B3LYP and MPW1PW91 functionals; calculated chemical shifts at B3LYP/6–31G(d,p) and MPW1PW91/6–31G+(d,p) showed much better correlations with the experimental data. Time dependent DFT applied on 2 at B3LYP/6–31G+(d,p) displayed a major absorption band at λ max = 299.01 nm using chloroform as solvent, 3.01 nm higher than the experimental value. In addition, The MeOH extract of the stems and some isolated compounds were tested in vitro against Pf 7G8 CQS and Pf Dd2 CQR strains of Plasmodium falciparum ; meanwhile, the CH 2 Cl 2 extract and the mixture of fatty acids ( 9 – 14) were tested on a resistant mycobacterial strain of Mycobacterium tuberculosis codified AC45. Stems disclosed a moderate antiplasmodial activity (IC 50 = 50 μg/mL) and the mixture 9 – 14 a potent antimycobacterial activity with a MIC = 9.52 μg/mL.Conclusion: these results tend to emphasize on the use of DFT studies when trying to learn more about the chemical structure through spectroscopic data of a natural compound, especially the case of a derivative of allantoin ( 1 ); essential oil from Cordia batesii presents interesting antimycobacterial activities which need to gain more visibility; further antiplasmodial tests should rely on batesiin ( 2 ) and other components of the species.

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