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Standardized biosynthesis of flavan-3-ols with effects on pancreatic beta-cell insulin secretion.

Chemler JA, Lock LT, Koffas MA, Tzanakakis ES

Department of Chemical and Biological Engineering, State University of New York at Buffalo, 904 Furnas Hall, Buffalo, NY, 14260, USA, mkoffas@eng.buffalo.edu.

Flavan-3-ols, such as green tea catechins represent a major group of phenolic compounds with significant medicinal properties. We describe the construction and optimization of Escherichia coli recombinant strains for the production of mono- and dihydroxylated catechins from their flavanone and phenylpropanoid acid precursors. Use of glucose minimal medium, Fe(II), and control of oxygen availability during shake-flask experiments resulted in production yield increases. Additional production improvement resulted from the use of medium rather than high-copy number plasmids and, in the case of mono-hydroxylated compounds, the addition of extracellular cofactors in the culture medium. The established metabolic engineering approach allowed the biosynthesis of natural catechins at high purity for assessing their possible insulinotropic effects in pancreatic beta-cell cultures. We demonstrated that (+)-afzelechin and (+)-catechin modulated the secretion of insulin by pancreatic beta-cells. These results indicate the potential of applying metabolic engineering approaches for the synthesis of natural and non-natural catechin analogues as drug candidates in diabetes treatments.

Published 20 November 2007 in Appl Microbiol Biotechnol, 77(4): 797-807.
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