Abdou Tchoukoua

A phytotoxic bicyclic lactone and other compounds from endophyte Xylaria curta

Abstract A new compound, (3aS,6aR)-4,5-dimethyl-3,3a,6,6a-tetrahydro-2H-cyclopenta [b]furan-2-one (2), along with two known metabolites, myrotheciumone A (1) and 4-oxo-4H-pyron-3-acetic acid (3) was isolated from the ethyl acetate extract of fermentation broth of Xylaria curta 92092022. The structures of these compounds were elucidated on the basis of spectroscopic methods (UV, IR, HRESITOFMS, 1D NMR, and 2D NMR). Compounds 1 and 2 showed moderate antibacterial and phytotoxic activities.

Synthesis and Evaluation of Anticancer Activity of O-allylchalconeDerivatives

A large number of novel O -allylchalcones were synthesized by Claisen Schmidt condensation reaction of O -allylvanillin 3 with appropriate substituted acetophenones 4a-h. These model chalcones 5a-h and their precursor O -allylvanillin were screened for their in vitro cytotoxicactivity against four human cancer cell lines. The most potent compound in this series with the IC 50 values below or around 10 μM were 5f against THP-1 cells (10.42 μM) and 5g against THP-1 (4.76 μM), DU-145 (5.21 μM), HL60 (7.90 μM), Hep-G2 (10.12 μM) and MCF-7 (10.32 μM).

Triumfettamide B, a New Ceramide from the Twigs of Triumfetta rhomboidea

A new ceramide (1) along with lupeol (2) and a mixture of β-sitosterol and stigmasterol, oleanolic acid (4), maslinic acid (5), β-sitosterol glucopyranoside (6), and trans-tiliroside (7) were isolated from Triumfetta rhomboidea (Tiliaceae). Their structures were determined on the basis of spectroscopic methods and mass spectrometry analysis, as well as by comparison of their physical and spectral data with those reported in the literature. The cytotoxic activity of crude extract, fractions, and some compounds were evaluated against human fibrosarcoma cancer cell line HT1080 using flow cytometry. The ethyl acetate fraction showed weak activity while the crude extract and the hexane and n-butanol fractions presented less than 50% of cell growth inhibition.

Albidosides H and I, two new triterpene saponins from the barks of Acacia albida Del. (Mimosaceae)

Abstract Two new triterpene saponins, albidosides H (1) and I (2), along with the three known saponins were isolated from the barks of Acacia albida. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies and mass spectrometry. Albidosides H (1) and I (2) were assayed for their cytotoxicity against HeLa and HL60 cells using MTT method.

Two new 5-deoxyflavan-3,4-diol glucosides from roots of Albizia chevalieri.

Phytochemical investigation of the roots of Albizia chevalieri led to the isolation of two new 5‐deoxyflavan‐3,4‐diol glucosides from roots of A. chevalieri, Chevalieriflavanosides A and B. Their structures were established by 2D NMR techniques, UV, IR, CD, and mass spectrometry. Cytotoxicity of the two compounds was evaluated against acute promyelocytic leukemia HL60 cells. The antibacterial activities of 1 and 2 also were evaluated against Pseudomonas aeruginosa and Staphylococcus aureus using the agar diffusion test. Copyright

Structure elucidation of new fusarielins from Fusarium sp. and their antimicrobial activity

Three new fusarielins, 3‐epi‐fusarielin H (1), 3‐O‐methyl‐fusarielin H (2), and 3‐O‐methyl‐epi‐fusarielin H (3), were isolated from the fungus Fusarium sp. together with the known analogues, fusarielins F (4) and G (5). The structures of these compounds were elucidated by analysis of their ESI‐HRTOFMS, 1D and 2D NMR spectroscopic data. The new compounds exhibited weak antibacterial effect against Staphylococcus aureus.

A new eremophilane sesquiterpene from the fungus Xylaria sp. V-27 and inhibition activity against degranulation in RBL-2H3 cells

A new eremophilane sesquiterpene, 13,13-dimethoxyintegric acid (1), together with known compound integric acid (2) have been isolated from a fungus, Xylaria sp. V-27, obtained from a dead branch. The structure of 1 was established by means of spectroscopic analyses. 1 and 2 promoted growth restoring activity against the mutant yeast strain (Saccharomyces cerevisiae (zds1Δ erg3Δ pdr1Δ pdr3Δ)) and inhibited degranulation of rat basophilic leukemia RBL-2H3 cells stimulated by immnunoglobulin G + 2,4-dinitrophenylated-bovine serum albumin (IgE+DNP-BSA), thapsigargin and A23187.