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Keywords = diasteroisomer

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21 pages, 2245 KiB  
Article
New Hydroxylactones and Chloro-Hydroxylactones Obtained by Biotransformation of Bicyclic Halolactones and Their Antibacterial Activity
by Małgorzata Grabarczyk, Anna Duda-Madej, Fedor Romanenko, Gabriela Maciejewska, Wanda Mączka, Agata Białońska and Katarzyna Wińska
Molecules 2024, 29(12), 2820; https://doi.org/10.3390/molecules29122820 - 13 Jun 2024
Viewed by 1196
Abstract
The aim of this study was to obtain new halolactones with a gem-dimethyl group in the cyclohexane ring (at the C-3 or C-5 carbon) and a methyl group in the lactone ring and then subject them to biotransformations using filamentous fungi. Halolactones in [...] Read more.
The aim of this study was to obtain new halolactones with a gem-dimethyl group in the cyclohexane ring (at the C-3 or C-5 carbon) and a methyl group in the lactone ring and then subject them to biotransformations using filamentous fungi. Halolactones in the form of mixtures of two diasteroisomers were subjected to screening biotransformations, which showed that only compounds with a gem-dimethyl group located at the C-5 carbon were transformed. Strains from the genus Fusarium carried out hydrolytic dehalogenation, while strains from the genus Absidia carried out hydroxylation of the C-7 carbon. Both substrates and biotransformation products were then tested for antimicrobial activity against multidrug-resistant strains of both bacteria and yeast-like fungi. The highest antifungal activity against C. dubliniensis and C. albicans strains was obtained for compound 5b, while antimicrobial activity against S. aureus MRSA was obtained for compound 4a. Full article
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11 pages, 2989 KiB  
Article
The Discovery of Acremochlorins O-R from an Acremonium sp. through Integrated Genomic and Molecular Networking
by Ge Cui, Luning Zhou, Hanwei Liu, Xuan Qian, Pengfei Yang, Leisha Cui, Pianpian Wang, Dehai Li, Jaclyn M. Winter and Guangwei Wu
J. Fungi 2024, 10(5), 365; https://doi.org/10.3390/jof10050365 - 20 May 2024
Cited by 2 | Viewed by 1764
Abstract
The fermentation of a soil-derived fungus Acremonium sp. led to the isolation of thirteen ascochlorin congeners through integrated genomic and Global Natural Product Social (GNPS) molecular networking. Among the isolated compounds, we identified two unusual bicyclic types, acremochlorins O (1) and [...] Read more.
The fermentation of a soil-derived fungus Acremonium sp. led to the isolation of thirteen ascochlorin congeners through integrated genomic and Global Natural Product Social (GNPS) molecular networking. Among the isolated compounds, we identified two unusual bicyclic types, acremochlorins O (1) and P (2), as well as two linear types, acremochlorin Q (3) and R (4). Compounds 1 and 2 contain an unusual benzopyran moiety and are diastereoisomers of each other, the first reported for the ascochlorins. Additionally, we elucidated the structure of 5, a 4-chloro-5-methylbenzene-1,3-diol with a linear farnesyl side chain, and confirmed the presence of eight known ascochlorin analogs (6–13). The structures were determined by the detailed interpretation of 1D and 2D NMR spectroscopy, MS, and ECD calculations. Compounds 3 and 9 showed potent antibacterial activity against Staphylococcus aureus and Bacillus cereus, with MIC values ranging from 2 to 16 μg/mL. Full article
(This article belongs to the Special Issue Fungal Metabolism in Filamentous Fungi: 2nd Edition)
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11 pages, 1745 KiB  
Article
A Biomimetic Approach to Premyrsinane-Type Diterpenoids: Exploring Microbial Transformation to Enhance Their Chemical Diversity
by Felipe Escobar-Montaño, Antonio J. Macías-Sánchez, José M. Botubol-Ares, Rosa Durán-Patrón and Rosario Hernández-Galán
Plants 2024, 13(6), 842; https://doi.org/10.3390/plants13060842 - 14 Mar 2024
Cited by 2 | Viewed by 1520
Abstract
Premyrsinane-type diterpenoids have been considered to originate from the cyclization of a suitable 5,6- or 6,17-epoxylathyrane precursor. Their biological activities have not been sufficiently explored to date, so the development of synthetic or microbial approaches for the preparation of new derivatives would be [...] Read more.
Premyrsinane-type diterpenoids have been considered to originate from the cyclization of a suitable 5,6- or 6,17-epoxylathyrane precursor. Their biological activities have not been sufficiently explored to date, so the development of synthetic or microbial approaches for the preparation of new derivatives would be desirable. Epoxyboetirane A (4) is an 6,17-epoxylathyrane isolated from Euphorbia boetica in a large enough amount to be used in semi-synthesis. Transannular cyclization of 4 mediated by Cp2TiIIICl afforded premyrsinane 5 in good yield as an only diasteroisomer. To enhance the structural diversity of premyrsinanes so their potential use in neurodegenerative disorders could be explored, compound 5 was biotransformed by Mucor circinelloides NRRL3631 to give rise to hydroxylated derivatives at non-activated carbons (6–7), all of which were reported here for the first time. The structures and absolute configurations of all compounds were determined through extensive NMR and HRESIMS spectroscopic studies. Full article
(This article belongs to the Section Phytochemistry)
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18 pages, 2136 KiB  
Article
Synthesis of New Brassinosteroid 24-Norcholane Type Analogs Conjugated in C-3 with Benzoate Groups
by Karoll Ferrer, Katy Díaz, Miroslav Kvasnica, Andrés F. Olea, Mauricio Cuellar and Luis Espinoza
Molecules 2021, 26(4), 1173; https://doi.org/10.3390/molecules26041173 - 22 Feb 2021
Cited by 6 | Viewed by 3144
Abstract
The metabolism of brassinosteroid leads to structural modifications in the ring skeleton or the side alkyl chain. The esterification and glycosylation at C-3 are the most common metabolic pathways, and it has been suggested that conjugate brassinosteroids are less active or inactive. In [...] Read more.
The metabolism of brassinosteroid leads to structural modifications in the ring skeleton or the side alkyl chain. The esterification and glycosylation at C-3 are the most common metabolic pathways, and it has been suggested that conjugate brassinosteroids are less active or inactive. In this way, plants regulate the content of active brassinosteroids. In this work, the synthesis of brassinosteroid 24-norcholane type analogs conjugated at C-3 with benzoate groups, carrying electron donor and electron attractant substituents on the aromatic ring, is described. Additionally, their growth-promoting activities were evaluated using the Rice Lamina Inclination Test (RLIT) and compared with that exhibited by brassinolide (used as positive control) and non-conjugated analogs. The results indicate that at the lowest tested concentrations (10−8–10−7 M), all analogs conjugated at C-3 exhibit similar or higher activities than brassinolide, and the diasteroisomers with S configuration at C-22 are the more active ones. Increasing concentration (10−6 M) reduces the biological activities of analogs as compared to brassinolide. Full article
(This article belongs to the Special Issue Synthesis and Bioanalysis of Steroids and Steroid Biosynthesis Inhibitors)
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13 pages, 1556 KiB  
Article
Influence of Cooking (Microwaving and Broiling) on Cylindrospermopsin Concentration in Muscle of Nile Tilapia (Oreochromis niloticus) and Characterization of Decomposition Products
by Ana I. Prieto, Remedios Guzmán-Guillén, Rocío Valderrama-Fernández, Ángeles Jos and Ana M. Cameán
Toxins 2017, 9(6), 177; https://doi.org/10.3390/toxins9060177 - 26 May 2017
Cited by 13 | Viewed by 4285
Abstract
Cylindrospermopsin (CYN) has become increasingly important as a freshwater algal toxin, showing cytotoxic effects. This toxin is able to bioaccumulate in freshwater food webs, representing a serious human health problem. Normally, fish is cooked before consumption, and CYN concentration can be altered. For [...] Read more.
Cylindrospermopsin (CYN) has become increasingly important as a freshwater algal toxin, showing cytotoxic effects. This toxin is able to bioaccumulate in freshwater food webs, representing a serious human health problem. Normally, fish is cooked before consumption, and CYN concentration can be altered. For the first time, the effects of microwaving and broiling for 1 and 2 min on CYN concentration and its decomposition products in fish muscle (Oreochromis niloticus) contaminated in the laboratory were investigated, using UPLC-MS/MS and Orbitrap. The results show that cooking the fish reduced unconjugated CYN levels by 11, 10 and 15% after microwaving for 1 and 2 min, and broiling for 2 min, respectively, compared to control fish. Different CYN decomposition products with m/z 416.1234 (7-epi-CYN) and m/z 336.16663 (diasteroisomers C-3A, C-3C, C-3D, C-3E, C-3F) are generated in fish samples submitted to cooking. Based on the relative abundance of the decomposition products, the possible degradation pathways taking place by microwaving may be through the formation of 7-epi-CYN and m/z 336.16663 compounds, whereas in the case of broiling the last route is the only one observed in this study. The influence of cooking and the toxicity characterization of the degradation products generated in CYN-contaminated fish are of importance for more realistic risk evaluation related to their consumption. Full article
(This article belongs to the Section Marine and Freshwater Toxins)
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9 pages, 333 KiB  
Article
An Efficient Synthesis of Enantiopure (R)-heteroarylpyrimidine Analogs
by Xiu-Yan Yang, Guang-Qiang Xia, Xiao-Kui Wang, Zhi-Bing Zheng, Dong-Mei Zhao, Guo-Ming Zhao and Song Li
Molecules 2013, 18(9), 11144-11152; https://doi.org/10.3390/molecules180911144 - 11 Sep 2013
Cited by 2 | Viewed by 5702
Abstract
An efficient synthesis of enantiopure (R)-heteroarylpyrimidine analogs is described here, which involves introduction of a chiral group, formation and separation of diasteroisomers and final transformation of an amide to an ester. The absolute configuration of the enantiopure HAPs is confirmed by [...] Read more.
An efficient synthesis of enantiopure (R)-heteroarylpyrimidine analogs is described here, which involves introduction of a chiral group, formation and separation of diasteroisomers and final transformation of an amide to an ester. The absolute configuration of the enantiopure HAPs is confirmed by X-ray analysis of their intermediates. Full article
(This article belongs to the Section Medicinal Chemistry)
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