Volume 94, October 2013, Pages 284–293
Highlights
- •
- Four anthocyanin compounds from Staghorn sumac were fully characterized using 1H, 13C and 2D NMR spectroscopic techniques.
- •
- 7-O-methyl anthocyanins were discovered, discounting earlier accounts of 3′O-methyl derivatives.
- •
- Two pyranoanthocyanin aglycones (Sumadin A and Sumadin B) are also reported.
Abstract
The six major anthocyanins found in the burgundy coloured fruits of Staghorn sumac (Rhus typhina L.) were isolated and the structures of four compounds were determined by NMR spectroscopic methods as being: 7-O-methyl-delphinidin-3-O-(2″galloyl)-β-d-galactopyranoside; 7-O-methyl-cyanidin-3-O-(2″galloyl)-β-d-galactopyranoside; 7-O-methyl-delphinidin-3-O-(2″′galloyl)-β-d-galactopyranoside-4-vinyl-catechol-3″-O-β-d-glucopyranoside; and 7-O-methyl-cyanidin-3-O-(2″′galloyl)-β-d-galactopyranoside-4-vinyl-catechol-3″-O-β-d-glucopyranoside, respectively. Additionally, two related anthocyanin compounds, cyanidin-3-O-(2″galloyl)-β-d-galactopyranoside and 7-O-methyl-cyanidin-3-O-β-d-galactopyranoside
were also recovered, with NMR spectroscopic values closely matching
previous reports from other plant species. The prevalence of 7-O-methyl
anthocyanins and their galloylated derivatives in sumac is highly
unusual, and warrants special attention. Additionally, the in planta occurrence of two 7-O-methyl-pyranoanothocyanin-vinyl-catechol
aglycones, Sumadin A and Sumadin B, and their derivatives is noted. To
our knowledge, E-ring glycosylated vinyl-catechol pyranoanthocyanins
were previously unknown.
Graphical abstract
Staghorn
sumac fruits were found to contain a rich assortment of anthocyanins,
including pyranoanthocyanins displaying distinctive UV–Vis absorption
spectra. Structures were characterized by UPLC–ESI-MS and NMR
spectroscopy.
Keywords
- Staghorn sumac;
- Rhus typhina;
- Anacardiaceae;
- Vinyl-catechol;
- Pyranoanthocyanin;
- Anthocyanin;
- Sumadin
Crown copyright © 2013 Published by Elsevier Ltd. All rights reserved.
