Production of deuterated cyanidin 3-O-glucoside from recombinant Escherichia coli

Abstract

Anthocyanins are plant secondary metabolites that, despite their chemical instability, have found many applications as natural food colorants. They are also known for their beneficial health effects because of their antioxidant and anticancer properties. More stable versions of these molecules, particularly at neutral pH conditions, are required to study the anthocyanin pharmacokinetic properties and obtain effective therapeutic results. In the present report, a cost-effective technique was developed to prepare the deuterated anthocyanin using recombinant Escherichia coli as a production host and deuterated glycerol and D2O in the culture media. This approach resulted in the formation of endogenous deuterated uridine 5′-diphosphate-glucose that was further incorporated by the recombinant anthocyanin pathway, resulting in the formation of deuterated cyanidin 3-O-glucoside (C3G). The deuterium exchange of O–D and C–D were studied by liquid chromatography (LC)–mass spectrometry and NMR analysis. The labeled C3G, purified by high-performance LC showed a stable nature at pH 7.0 as compared to nondeuterated C3G.