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The stereostructure of candicidin D.
PublikacjaThe candicidin D stereostructure was established based on NMR studies including DQF-COSY, ROESY, HSQC and HMBC experiments. The relative configurations of the candicidin D stereogenic centers were assigned as the following: 9R*, 11S*, 13S*, 15R*, 17S*, 18R*, 19S*, 21R*, 36S*, 37R*, 38S*, 40S* and 41S*. The geometry of the heptaene chromophore was defined as 22E, 24E, 26Z, 28Z, 30E, 32E and 34E.
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The complete stereochemistry of the antibiotic candicidin A3 (syn. ascosin A3, levorin A3)
PublikacjaHerein, the stereostructure of the aromatic heptaene macrolide (AHM) antifungal antibiotic candicidin A3 (syn. ascosin A3, levorin A3) has been established upon the 2D NMR studies, consisting of DQF-COSY, TOCSY, ROESY, HSQC and HMBC experiments, as well as upon extensive molecular dynamics simulations. The geometry of the heptaenic chromophore was defined as: (22E, 24E, 26Z, 28Z, 30E, 32E, 34E). The previously unreported absolute...
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Analytical studies on ascosin, candicidin and levorin multicomponent antifungal antibiotic complexes. The stereostructure of ascosin A2
PublikacjaIn the class of polyene macrolides, there is a subgroup of aromatic heptaenes, which exhibit the highest antifungal activity within this type of antibiotics. Yet, due to their complex nature, aromatic heptaenes were not extensively studied and their potential as drugs is currently underexploited. Moreover, there are many inconsistencies in the literature regarding the composition and the structures of the individual components...
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Light-Induced Transformation of the Aromatic Heptaene Antifungal Antibiotic Candicidin D into Its All-Trans Isomer
PublikacjaIllumination of the aromatic heptaene macrolide antifungal antibiotic candicicin D with UV light results in an isomerization of the molecule. The product formed after irradiation of the candicidin complex with UV light (λ=365nm), namely, iso-candicidin D, was isolated and subjected to 2D NMR studies, consisting of DQF-COSY, ROESY, TOCSY, HSQC, and HMBC experiments. The obtained spectral data unambiguously evidenced that iso-candicidin...
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Aromatic heptaene antibiotics as an alternative for synthetic triazole fungicides in plant protection
PublikacjaAn in vitro antifungal activity of candicidin and ascosin antibiotics (0,01-10 μg/mL) towards representative strains of phytopathogenic fungi was detd. Both compds. exhibited similar half max. effective concns. inhibiting growth of the fungi as that of tebuconazole used for comparison.
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Heptaene macrolides biosynthesis by Streptomyces species
PublikacjaPolyene macrolides are one of the groups of secondary metabolites, generated by microorganisms belonging to the Streptomyces genus. These compounds, containing 3 - 7 conjugated double bonds systems in their molecules exhibit high antifungal activity against a broad spectrum of fungal pathogens with heptaenes demonstrating the highest antifungal potential. At the large extent, efficiency of biosynthesis of these natural products...
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Chemical and biological stability of polyene macrolides
PublikacjaThe polyene macrolide antibiotics have been used in an-tifungal therapy since first o f them were discovered in 1950's. Up to now, four polyene macrolides are being used in medical practice, namely amphotericin B, nystatin, candi-cidin and pimaricin.The antifungal activity and mode of ac-tion of polyene macrolides is determined by their structure, chemical and physical properties.The main fragment of polyene...
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Quest for the Molecular Basis of Improved Selective Toxicity of All-Trans Isomers of Aromatic Heptaene Macrolide Antifungal Antibiotics
PublikacjaThree aromatic heptaene macrolide antifungal antibiotics, Candicidin D, Partricin A (Gedamycin) and Partricin B (Vacidin) were subjected to controlled cis-trans to all trans photochemical isomerization. The obtained all-trans isomers demonstrated substantially improved in vitro selective toxicity in the Candida albicans cells: human erythrocytes model. This effect was mainly due to the diminished hemotoxicity. The molecular modeling...