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Cryptophycins are naturally occurring cytotoxins with great potential for chemotherapy. Since targeted therapy provides new perspectives for treatment of cancer, new potent analogues of cytotoxic agents containing functional groups for conjugation to homing devices are required. We describe the design, synthesis and biological evaluation of three new unit B cryptophycin analogues. The O-methyl gro
Flavin-dependent halogenases are known to regioselectively introduce halide substituents into aromatic moieties, for example, the indole ring of tryptophan. The process requires halide salts and oxygen instead of molecular halogen in the chemical halogenation. However, the reduced cofactor flavin adenine dinucleotide (FADH 2 ) has to be regenerated using a flavin reductase. Consequently, coupled
In this chapter, we analyze Finnish and Swedish economic history research on these countries’ common past (prior to 1809) and the early modern era (defined here as between 1500 and 1850). Using extensive bibliometric databases, we show that even when they focus on the early modern era, economic historians most often analyze Finland and Sweden in terms of their modern borders. Researchers based in
Flavin-dependent halogenases selectively introduce halogen substituents into (hetero-)aromatic substrates and require only molecular oxygen and halide salts for this regioselective oxidative CH-functionalization. Genomic analysis of Xanthomonas campestris pv. campestris B100 identified three novel putative members of this enzyme class. They were shown to introduce halogen substituents into, e. g.,
Avian Malaria infects thousands of species of birds across the Aves class. The most widespread (geographically and phylogenetically)morphological species is Plasmodium relictum, and of that, the mitochondrial lineage of SGS1 is the most common and invasive. It infects146 bird species, with large differences in infection outcome, from low intensity chronic disease to shorter, highly virulent infect
A re-cultivation of the thermophilic fungus Aspergillus terreus TM8, and working up of its extract afforded the dichloro-benzophenone derivative, dihydrogeodin (1) in addition to the butyrolactones I (2), V (3) and VI (4). A literature surveying revealed one recent structural assignment trial for dihydrogeodin (1), however, with some inaccuracies. We report herein a full assignment of dihydrogeodi
As a continuation of our earlier research concerning the investigation of microbial bioactive secondary metabolites from the terrestrial Penicillium sp.KH Link 1809 isolate KHMM, the fungus was re-cultivated on a large scale to explore its bioactive compounds intensively. Fifteen compounds, including seven alkaloids (1-7), one sesquiterpene (8), an acetylenic system (9), two sterols, and sphengoli
Two new ergostane-type steroids named tiamenones A and B (1–2) were isolated from the bark of Entandrophragma angolense (Meliaceae) along with ten known compounds identified as 20S-hydroxy-4,6,24(28)-ergostatrien-3-one (3), 3β,7α,20β-trihydroxyergosta-5,24(28)-diene (4), 3β,5α-dihydroxyergosta-7,22-diene (5), stigmasterol, β-sitosterol, β-amyrin, oleanolic acid, asperphenamate, sucrose and daucost
A new series of 4-arylamino-3-nitrocoumarin analogues (4–18) have been synthesized and characterized by sophisticated spectroscopic techniques (1H NMR, 13C NMR) and mass spectrometry. All the new synthesized compounds were evaluated for their in vitro cytotoxic activity against the human cervix carcinoma cell line (KB-3-1) using resazurin assay with (+)-griseofulvin as the positive control (IC50 =
Cyclic RGD peptides are well-known ligands of integrins. The integrins αVβ3 and α5β1 are involved in angiogenesis, and integrin αVβ3 is abundantly present on cancer cells, thus representing a therapeutic target. Hence, synthetic and biophysical studies continuously are being directed towards the understanding of ligand-integrin interaction. In this context, the development of versatile synthetic s
Flavin-dependent halogenases regioselectively introduce halide substituents into electron-rich substrates under mild reaction conditions. For the enzyme Xcc4156 from Xanthomonas campestris, the structure of a complex with the cofactor flavin adenine dinucleotide (FAD) and a bromide ion would be of particular interest as this enzyme exclusively brominates model substrates in vitro. Apo Xcc4156 crys
The phytochemical exploration of the Entandrophragma candollei stem bark extract led to the isolation and identification of twenty compounds including three undescribed phragmalin-class limonoids named encandollens C–E (1–3), the undescribed protolimonoid 5 together with sixteen known compounds. The structures of all the isolated compounds were determined by interpretation of their spectroscopic a
Halogen substituents often lead to a profound effect on the biological activity of organic compounds. Flavin-dependent halogenases offer the possibility of regioselective halogenation at non-activated carbon atoms, while employing only halide salts and molecular oxygen. However, low enzyme activity, instability, and narrow substrate scope compromise the use of enzymatic halogenation as an economic
