TY - JOUR A1 - Nchiozem-Ngnitedem, Vaderament-Alexe A1 - Sperlich, Eric A1 - Matieta, Valaire Yemene A1 - Kuete, Jenifer Reine Ngnouzouba A1 - Kuete, Victor A1 - Omer, Ejlal A. A. A1 - Efferth, Thomas A1 - Schmidt, Bernd T1 - Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues JF - Journal of natural products : Lloydia N2 - 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. KW - Antimicrobial activity KW - Bacteria KW - Ethers KW - Flavonoids KW - Mixtures Y1 - 2023 U6 - https://doi.org/10.1021/acs.jnatprod.3c00219 SN - 0163-3864 SN - 1520-6025 VL - 86 IS - 6 SP - 1520 EP - 1528 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Unuabonah, Emmanuel I. A1 - Kolawole, Matthew O. A1 - Agunbiade, Foluso O. A1 - Omorogie, Martins O. A1 - Koko, Daniel T. A1 - Ugwuja, Chidinma G. A1 - Ugege, Leonard E. A1 - Oyejide, Nicholas E. A1 - Günter, Christina A1 - Taubert, Andreas T1 - Novel metal-doped bacteriostatic hybrid clay composites for point-of-use disinfection of water JF - Journal of Environmental Chemical Engineering N2 - 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. KW - Kaolinite KW - Composites KW - Bacteria KW - Breakthrough time KW - Regeneration Y1 - 2017 U6 - https://doi.org/10.1016/j.jece.2017.04.017 SN - 2213-3437 VL - 5 SP - 2128 EP - 2141 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zühlke, Martin A1 - Meiling, Till Thomas A1 - Roder, Phillip A1 - Riebe, Daniel A1 - Beitz, Toralf A1 - Bald, Ilko A1 - Löhmannsröben, Hans-Gerd A1 - Janßen, Traute A1 - Erhard, Marcel A1 - Repp, Alexander T1 - Photodynamic inactivation of E. coli bacteria via carbon nanodots JF - ACS omega / American Chemical Society N2 - 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. KW - Bacteria KW - Genetics KW - Fluorescence KW - Photodynamics KW - Irradiation Y1 - 2021 U6 - https://doi.org/10.1021/acsomega.1c01700 SN - 2470-1343 VL - 6 IS - 37 SP - 23742 EP - 23749 PB - ACS Publications CY - Washington, DC ER -