@phdthesis{TshitengeTshitenge2019, author = {Tshitenge Tshitenge, Dieudonn{\´e}}, title = {Isolation and Structural Elucidation of Novel Anti-Infective Naphthylisoquinoline Alkaloids from Ancistrocladus ealaensis, and Phytochemical Analysis of Two Congolese Medicinal Plants}, doi = {10.25972/OPUS-15417}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154175}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Herein described are the isolation, structural elucidation, and biological evaluation of highly thrilling monomeric and dimeric new naphthylisoquinoline alkaloids from A. ealaensis. The separation, chiral resolution, and characterization of a series of stereoisomeric 2,3-dihydrobenzofuran neolignans are also reported. The analytical and phytochemical analysis on two Congolese antimalarial herbal drugs is part of the last chapter of the results. In this last case, major concerns on widely used Congolese herbal drugs are discussed.}, subject = {Naphthylisochinolinalkaloide}, language = {en} } @article{TshitengeTshitengeBruhnFeineisetal.2019, author = {Tshitenge Tshitenge, Dieudonn{\´e} and Bruhn, Torsten and Feineis, Doris and Mudogo, Virima and Kaiser, Marcel and Brun, Reto and Bringmann, Gerhard}, title = {An unusually broad series of seven cyclombandakamines, bridged dimeric naphthylisoquinoline alkaloids from the Congolese liana Ancistrocladus ealaensis}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, doi = {10.1038/s41598-019-46336-z.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200759}, pages = {9812}, year = {2019}, abstract = {A series of seven unusual dimeric naphthylisoquinoline alkaloids was isolated from the leaves of the tropical liana Ancistrocladus ealaensis J. L{\´e}onard, named cyclombandakamine A (1), 1-epi-cyclombandakamine A (2), and cyclombandakamines A3-7 (3-7). These alkaloids have a chemically thrilling structural array consisting of a twisted dihydrofuran-cyclohexenone-isochromene system. The 1′″-epimer of 4, cyclombandakamine A1 (8), had previously been discovered in an unidentified Ancistrocladus species related to A. ealaensis. Both lianas produce the potential parent precursor, mbandakamine A (9), but only A. ealaensis synthesizes the corresponding cyclized form, along with a broad series of slightly modified analogs. The challenging isolation required, besides multi-dimensional chromatography, the use of a pentafluorophenyl stationary phase. Featuring up to six stereocenters and two types of chiral axes, their structures were elucidated by means of 1D and 2D NMR, HRESIMS, in combination with oxidative chemical degradation experiments as well as chiroptical (electronic circular dichroism spectroscopy) and quantum chemical calculations. Compared to the 'open-chain' parent compound 9, these dimers displayed rather moderate antiplasmodial activities.}, language = {en} } @article{TshitengeFeineisMudogoetal.2017, author = {Tshitenge, Dieudonn{\´e} Tshitenge and Feineis, Doris and Mudogo, Virima and Kaiser, Marcel and Brun, Reto and Bringmann, Gerhard}, title = {Antiplasmodial Ealapasamines A-C,'Mixed' Naphthylisoquinoline Dimers from the Central African Liana Ancistrocladus ealaensis}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, number = {5767}, doi = {10.1038/s41598-017-05719-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170645}, year = {2017}, abstract = {Three unusual heterodimeric naphthylisoquinoline alkaloids, named ealapasamines A-C (1-3), were isolated from the leaves of the tropical plant Ancistrocladus ealaensis J. L{\´e}onard. These 'mixed', constitutionally unsymmetric dimers are the first stereochemically fully assigned cross-coupling products of a 5,8′- and a 7,8′-coupled naphthylisoquinoline linked via C-6′ in both naphthalene portions. So far, only two other West and Central Ancistrocladus species were known to produce dimers with a central 6,6″-axis, yet, in contrast to the ealapasamines, usually consisting of two 5,8′-coupled monomers, like e.g., in michellamine B. The new dimers 1-3 contain six elements of chirality, four stereogenic centers and the two outer axes, while the central biaryl axis is configurationally unstable. The elucidation of the complete stereostructures of the ealapasamines was achieved by the interplay of spectroscopic methods including HRESIMS, 1D and 2D NMR (in particular ROESY measurements), in combination with chemical (oxidative degradation) and chiroptical (electronic circular dichroism) investigations. The ealapasamines A-C display high antiplasmodial activities with excellent half-maximum inhibition concentration values in the low nanomolar range.}, language = {en} }