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Updated: Dec 30, 2025

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
Synthesis of Nontoxic Protoflavone Derivatives through Selective Continuous-Flow Hydrogenation of the Flavonoid
Sándor B Ötvös1,2, Máté Vágvölgyi3, Gábor Girst1,3
1Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös u. 6, 6720, Szeged, Hungary.
Abstract:
Protoflavones are unique natural flavonoids with a non-aromatic B-ring, known for their potent antitumor properties. However, their cytotoxicity represents a strong limitation in the further exploration of their pharmacological potential. In the current study, we sought to selectively saturate the p-quinol B-ring of protoapigenone and that of its 1'-O-butyl ether, in order to obtain non-toxic protoflavone analogues expressing the dihydro- or tetrahydroprotoflavone structure also occurring in nature. The benefits of a strictly controlled continuous-flow environment in combination with on-demand electrolytic H2 gas generation were exploited to suppress undesired side reactions and to safely and selectively yield the desired substances. The obtained tetrahydroprotoflavones were free of the cytotoxicity of their parent compounds, and, even though tetrahydroprotoapigenone 1-O-butyl ether showed a weak inhibition of DNA damage response through Chk1, neither compounds influenced the cytotoxicity of doxorubicin either.
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