Sulfated flavanones and dihydroflavonols from willow

Clarice Noleto-Dias; Claudia Harflett; Michael H Beale; Jane L Ward

doi:10.1016/j.phytol.2019.11.008

Sulfated flavanones and dihydroflavonols from willow

Phytochem Lett. 2020 Feb:35:88-93. doi: 10.1016/j.phytol.2019.11.008.

Authors

Clarice Noleto-Dias¹, Claudia Harflett¹, Michael H Beale¹, Jane L Ward¹

Affiliation

¹ Department of Computational and Analytical Sciences, Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK.

Abstract

Phytochemical profiling of a hybrid species of willow, Salix × alberti L. (S. integra Thunb. × Salix suchowensis W.C. Cheng ex G.Zhu) revealed four sulfated flavonoids, which were then isolated from young stem tissue. The structures of dihydroflavonols (flavanonols) taxifolin-7-sulfate (1) and dihydrokaempferol-7-sulfate (2) and flavanones, eridictyol-7-sulfate (3) and naringenin-7-sulfate (4) were elucidated through NMR spectroscopy and high-resolution mass spectrometry. The identified sulfated flavanones and dihydroflavonols have not been previously seen in plants, but the former have been partially characterised as metabolites in mammalian metabolism of dietary flavonoids. In addition to providing full spectroscopic characterisation of these metabolites for the first time, we also compared the in vitro antioxidant properties, via the DPPH radical scavenging assay, of the parent and sulfated flavanones, which showed that 7-sulfation of taxifolin and eriodictyol attenuates but does not remove anti-oxidant activity.

Keywords: Antioxidant; S. × alberti L. (S. integra Thunb. × S. suchowensis) hybrid; Salicaceae; Sulfated dihydroflavonols; Sulfated flavanones; Willow.