Microbial Transformation of Cycloastragenol and Astragenol by Endophytic Fungi Isolated from Astragalus Species

Journal of Natural Products
2019.0

Abstract

Biotransformation of Astragalus sapogenins (cycloastragenol (1) and astragenol (2)) by Astragalus species originated endophytic fungi resulted in the production of five new metabolites (3, 7, 10, 12, 14) together with 10 known compounds. The structures of the new compounds were established by NMR spectroscopic and HRMS analysis. Oxygenation, oxidation, epoxidation, dehydrogenation, and ring cleavage reactions were observed on the cycloartane (9,19-cyclolanostane) nucleus. The ability of the compounds to increase telomerase activity in neonatal cells was also evaluated. After prescreening studies to define potent telomerase activators, four compounds were selected for subsequent bioassays. These were performed using very low doses ranging from 0.1 to 30 nM compared to the control cells treated with DMSO. The positive control cycloastragenol and 8 were found to be the most active compounds, with 5.2- (2 nM) and 5.1- (0.5 nM) fold activations versus DMSO, respectively. At the lowest dose of 0.1 nM, compounds 4 and 13 provided 3.5- and 3.8-fold activations, respectively, while cycloastragenol showed a limited activation (1.5-fold).

Knowledge Graph

Similar Paper

Microbial Transformation of Cycloastragenol and Astragenol by Endophytic Fungi Isolated from <i>Astragalus</i> Species
Journal of Natural Products 2019.0
Cycloartane Triterpenoids from <i>Astragalus bicuspis</i>
Journal of Natural Products 2008.0
Secondary Metabolites from the Roots of <i>Astragalus trojanus</i>
Journal of Natural Products 1999.0
Secoemestrin D, a Cytotoxic Epitetrathiodioxopiperizine, and Emericellenes A–E, Five Sesterterpenoids from <i>Emericella</i> sp. AST0036, a Fungal Endophyte of <i>Astragalus lentiginosus</i>1
Journal of Natural Products 2013.0
Secoemestrin D, a Cytotoxic Epitetrathiodioxopiperizine, and Emericellenes A–E, Five Sesterterpenoids from <i>Emericella</i> sp. AST0036, a Fungal Endophyte of <i>Astragalus lentiginosus</i>1
Journal of Natural Products 2013.0
Chlorinated Dehydrocurvularins and Alterperylenepoxide A from <i>Alternaria</i> sp. AST0039, a Fungal Endophyte of <i>Astragalus lentiginosus</i>
Journal of Natural Products 2017.0
Microbial transformation of resveratrol by endophyte <i>Streptomyces</i> sp. A12 isolated from <i>Polygonum cuspidatum</i>
Natural Product Research 2018.0
Constituents of Astragalus membranaceus
Journal of Natural Products 1991.0
Isolation, identification, and bioactivity of microbial metabolites of cyclopamine and its congeners
Phytochemistry Letters 2015.0
Aspergillus fumigatus CY018, an endophytic fungus in Cynodon dactylon as a versatile producer of new and bioactive metabolites
Journal of Biotechnology 2004.0