ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Novel quercetin derivatives: synthesis and screening for anti-oxidant activity and aldose reductase inhibition
Miroslav Veverka, Ján Gallovič, Emil Švajdlenka, Eva Veverková, Naďa Prónayová, Ivana Miláčková, and Milan Štefek
Bel/Novamann International, s.r.o., 811 07 Bratislava, Slovakia
Abstract: The direct acylation of quercetin (I) with 3-chloro-2,2-dimethylpropanoyl chloride (II) gives a complex reaction mixture. The synthesis of different acylated quercetin with from mono- to tetra-O-substituted functions
was achieved in a simple procedure wherein the yield of isomers depended on the stoichiometric ratio of reagents. The crude
reaction mixtures were analysed (LC-MS) and compared with the isolated products. Unambiguous structural characterisation of
isomeric quercetin derivatives was confirmed by NMR analysis. In addition, the quercetin dimer can be obtained in a high yield
in the simple procedure. The anti-oxidant activity and aldose reductase inhibition of the compounds were screened with the
aim of providing bi-functional remedies to treat diabetic complications and other diseases where oxidative stress and the
polyol pathway are key etiological factors.
Keywords: quercetin – acylation – naphthoquinone – quercetin dimer – LC-MS – aldose reductase
Full paper is available at www.springerlink.com.
Chemical Papers 67 (1) 76–83 (2013)