Selective 4′-O-methylglycosylation of the pentahydroxy-flavonoid quercetin by Beauveria bassiana ATCC 7159 |
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Authors: | Jixun Zhan |
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Institution: | Southwest Center for Natural Products Research and Commercialization, Office of Arid Lands Studies, College of Agriculture and Life Sciences, The University of Arizona, 250 E. Valencia Road, Tucson, AZ 85706-6800, USA |
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Abstract: | Biotransformation of the pentahydroxy-flavonoid natural product, quercetin, by Beauveria bassiana ATCC 7159 afforded a new derivative, quercetin-4'-O-methyl-7-O-β-D-glucopyranoside, in 87% isolated yield suggesting that glucosylation of the substrate occurred with high selectivity at C–7-OH out of the five hydroxyl groups. Most of the product was isolated from the mycelium and the filtrate of the culture medium did not show any catalytic activity. The mycelium is capable of performing this biotransformation when suspended in buffers of pH 2.1 and 7.2, suggesting that intracellular enzymes are involved and that they are active at a wide range of extracellular pH. |
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Keywords: | 4'-O-methyl-glycosylation intracellular enzymes quercetin selectivity |
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