@article{NchiozemNgnitedemSperlichMatietaetal.2023, author = {Nchiozem-Ngnitedem, Vaderament-Alexe and Sperlich, Eric and Matieta, Valaire Yemene and Kuete, Jenifer Reine Ngnouzouba and Kuete, Victor and Omer, Ejlal A. A. and Efferth, Thomas and Schmidt, Bernd}, title = {Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues}, series = {Journal of natural products : Lloydia}, volume = {86}, journal = {Journal of natural products : Lloydia}, number = {6}, publisher = {American Chemical Society}, address = {Washington, DC}, issn = {0163-3864}, doi = {10.1021/acs.jnatprod.3c00219}, pages = {1520 -- 1528}, year = {2023}, abstract = {FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold.}, language = {en} } @article{UnuabonahKolawoleAgunbiadeetal.2017, author = {Unuabonah, Emmanuel Iyayi and Kolawole, Matthew O. and Agunbiade, Foluso O. and Omorogie, Martins O. and Koko, Daniel T. and Ugwuja, Chidinma G. and Ugege, Leonard E. and Oyejide, Nicholas E. and G{\"u}nter, Christina and Taubert, Andreas}, title = {Novel metal-doped bacteriostatic hybrid clay composites for point-of-use disinfection of water}, series = {Journal of Environmental Chemical Engineering}, volume = {5}, journal = {Journal of Environmental Chemical Engineering}, publisher = {Elsevier}, address = {Oxford}, issn = {2213-3437}, doi = {10.1016/j.jece.2017.04.017}, pages = {2128 -- 2141}, year = {2017}, abstract = {This study reports the facile microwave-assisted thermal preparation of novel metal-doped hybrid clay composite adsorbents consisting of Kaolinite clay, Carica papaya seeds and/or plantain peels (Musa paradisiaca) and ZnCl2. Fourier Transformed IR spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Brunauer-Emmett-Teller (BET) analysis are employed to characterize these composite adsorbents. The physicochemical analysis of these composites suggests that they act as bacteriostatic rather than bacteriacidal agents. This bacterostactic action is induced by the ZnO phase in the composites whose amount correlates with the efficacy of the composite. The composite prepared with papaya seeds (PS-HYCA) provides the best disinfection efficacy (when compared with composite prepared with Musa paradisiaca peels-PP-HYCA) against gram-negative enteric bacteria with a breakthrough time of 400 and 700 min for the removal of 1.5 x10(6) cfu/mL S. typhi and V. cholerae from water respectively. At 10(3) cfu/mL of each bacterium in solution, 2 g of both composite adsorbents kept the levels the bacteria in effluent solutions at zero for up to 24 h. Steam regeneration of 2 g of bacteria-loaded Carica papaya prepared composite adsorbent shows a loss of ca. 31\% of its capacity even after the 3rd regeneration cycle of 25 h of service time. The composite adsorbent prepared with Carica papaya seeds will be useful for developing simple point-of-use water treatment systems for water disinfection application. This composite adsorbent is comparatively of good performance and shows relatively long hydraulic contact times and is expected to minimize energy intensive traditional treatment processes.}, language = {en} } @article{ZuehlkeMeilingRoderetal.2021, author = {Z{\"u}hlke, Martin and Meiling, Till Thomas and Roder, Phillip and Riebe, Daniel and Beitz, Toralf and Bald, Ilko and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Janßen, Traute and Erhard, Marcel and Repp, Alexander}, title = {Photodynamic inactivation of E. coli bacteria via carbon nanodots}, series = {ACS omega / American Chemical Society}, volume = {6}, journal = {ACS omega / American Chemical Society}, number = {37}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {2470-1343}, doi = {10.1021/acsomega.1c01700}, pages = {23742 -- 23749}, year = {2021}, abstract = {The increasing development of antibiotic resistance in bacteria has been a major problem for years, both in human and veterinary medicine. Prophylactic measures, such as the use of vaccines, are of great importance in reducing the use of antibiotics in livestock. These vaccines are mainly produced based on formaldehyde inactivation. However, the latter damages the recognition elements of the bacterial proteins and thus could reduce the immune response in the animal. An alternative inactivation method developed in this work is based on gentle photodynamic inactivation using carbon nanodots (CNDs) at excitation wavelengths λex > 290 nm. The photodynamic inactivation was characterized on the nonvirulent laboratory strain Escherichia coli K12 using synthesized CNDs. For a gentle inactivation, the CNDs must be absorbed into the cytoplasm of the E. coli cell. Thus, the inactivation through photoinduced formation of reactive oxygen species only takes place inside the bacterium, which means that the outer membrane is neither damaged nor altered. The loading of the CNDs into E. coli was examined using fluorescence microscopy. Complete loading of the bacterial cells could be achieved in less than 10 min. These studies revealed a reversible uptake process allowing the recovery and reuse of the CNDs after irradiation and before the administration of the vaccine. The success of photodynamic inactivation was verified by viability assays on agar. In a homemade flow photoreactor, the fastest successful irradiation of the bacteria could be carried out in 34 s. Therefore, the photodynamic inactivation based on CNDs is very effective. The membrane integrity of the bacteria after irradiation was verified by slide agglutination and atomic force microscopy. The method developed for the laboratory strain E. coli K12 could then be successfully applied to the important avian pathogens Bordetella avium and Ornithobacterium rhinotracheale to aid the development of novel vaccines.}, language = {en} }