Simplicilones A and B Isolated from the Endophytic Fungus SPC3.

Two new tetracyclic polyketides with a spirocenter, simplicilones A (1) and B (2) were isolated from the broth-culture of the endophytic fungus Simplicilliumsubtropicum (SPC3) in the course of our screening for new bioactive secondary metabolites. This endophytoic fungus is naturally harboured in the fresh bark of the Cameroonian medicinal plant Duguetia staudtii (Engl. and Diels) Chatrou. The planar structures of the simplicilones were elucidated by MS and 1D as well as 2D NMR spectroscopic techniques. The relative configuration was assigned by NOESY experiments in conjunction with coupling constants; subsequently, the absolute configurations were assigned by the modified Mosher's method. The compounds showed weak cytotoxic effects against the cell line KB3.1 (in vitro cytotoxicity (IC50) = 25 µg/mL for 1, 29 µg/mL for 2), but were inactive against the tested Gram-positive and Gram-negative bacteria as well as fungi

Simplicilones A and B Isolated from the Endophytic Fungus Simplicillium subtropicum SPC3

Two new tetracyclic polyketides with a spirocenter, simplicilones A (1) and B (2) were isolated from the broth-culture of the endophytic fungus Simplicilliumsubtropicum (SPC3) in the course of our screening for new bioactive secondary metabolites. This endophytoic fungus is naturally harboured in the fresh bark of the Cameroonian medicinal plant Duguetia staudtii (Engl. and Diels) Chatrou. The planar structures of the simplicilones were elucidated by MS and 1D as well as 2D NMR spectroscopic techniques. The relative configuration was assigned by NOESY experiments in conjunction with coupling constants; subsequently, the absolute configurations were assigned by the modified Mosher’s method. The compounds showed weak cytotoxic effects against the cell line KB3.1 (in vitro cytotoxicity (IC50) = 25 µg/mL for 1, 29 µg/mL for 2), but were inactive against the tested Gram-positive and Gram-negative bacteria as well as fungi

Two xanthones and two rotameric (3⟶8) biflavonoids from the Cameroonian medicinal plant Allanblackia floribunda Oliv. (Guttiferae)

Two xanthones, 2-(3-hydroxy-3,3-dimethyldihydroallyl)-dihydro-6-deoxyisojacareubin (1) and dihydro-6-deoxyjacareubin (2), and two 3 ⟶ 8 rotameric biflavonoids, (2R,3S)-volkensiflavone-7-O-β-acetylglucopyranoside (3) and (2S,3S)-morelloflavone-7-O-β-acetylglucopyranoside (4), together with fifteen known compounds, were isolated from a dichloromethane/methanol (1:1, v/v) extract of the bark of the plant Allanblackia floribunda. The structures of the new compounds were elucidated by NMR spectroscopy and mass spectroscopic techniques and those of the known ones were deduced by comparison with data reported in the literature. The isolated biflavonoids were obtained as mixtures of conformers exhibiting duplicate NMR signals in solution at 25 °C and their respective absolute configurations were assigned using circular dichroism spectroscopy. Selected isolated compounds were assessed for their antibacterial and antioxidant propertie

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

Crystal structure, spectroscopic analysis, electronic properties and molecular docking study of costunolide for inhibitor capacity against Onchocerca volvulus main protease

Mountessou BYG, Mbobda ASW, Stammler H-G, et al. Crystal structure, spectroscopic analysis, electronic properties and molecular docking study of costunolide for inhibitor capacity against Onchocerca volvulus main protease. Journal of Molecular Structure. 2023;1282: 135185.Costunolide, a naturally occurring sesquiterpene lactone, was investigated experimentally and theoret-ically to determine the structural, electronic, spectroscopic, and chemical reactivity properties. As de-duced from a single crystal X-ray diffraction (XRD) analysis, the absolute configurations of the two chiral centres were assigned as (6R,7S). Vibrational frequencies (IR, UV and NMR), electronic properties (HOMO and LUMO), and the molecular structure of costunolide were investigated by DFT calculations using Gaus-sian 09 molecular package at the B3LYP/6-311 ++ G(d,p) level of theory. NMR chemical shifts were calcu-lated from the magnetic shielding tensors obtained through the gauge-independent atomic orbital (GIAO) method, while the UV-vis spectrum was simulated by time dependent-DFT (TD-DFT) calculations. All cal-culations showed correlations to experimental data. The 6-311 + G(2d,p) basis set was additionally used for better correlation in NMR studies. The first order hyperpolarizability value indicated that costunolide has nonlinear optical (NLO) properties. Costunolide stability arising from hyperconjugative interactions and charge delocalisation was analysed using natural bond orbital (NBO). Thermodynamic parameters also correlated in the temperature range 10 0-70 0 K. The molecular docking results showed that costuno-lide binds strongly to the Onchocerca volvulus main protease with a relative binding affinity of -5.94 kcal mol-1 and an inhibition constant of 44.61 mu M.(c) 2023 Elsevier B.V. All rights reserved