Differences in the structure of anthocyanins from the two amphibious plants, Lobelia cardinalis and Nesaea crassicaulis

Abstract

The foliar anthocyanin profiles of two amphibious plants, Nesaea crassicaulis and Lobelia cardinalis were analysed for the first time. N. crassicaulis produced very simple anthocyanins, achieving the highest concentrations when grown submerged. In contrast, L. cardinalis produced leaves with a high content of very complex, acylated anthocyanins, especially when growing emergent. Anthocyanins were separated by high performance liquid chromatography. Nesaea crassicaulis anthocyanins were identified according to their fragment mass spectra and ultra-visible-violet spectral characteristics and 1D and 2D NMR spectra as -3,5-di-O-β-glucosides of delphinidin, cyanidin, petunidin, malvidin and peonidin as well as cyanidine and peonidin-3-O-β-glucoside. In L. cardinalis cyanidin-3-O-[6-O-(4-O-E-p-coumaroyl-O-α-rhamnopyranosyl)-β-glucopyrano]-5-O-β-glucopyranoside was the major anthocyanin and contributed more than 98% of total anthocyanin content. The remaining 2% was made up by cyanidin-3-O-[6-O-(4-O-E-caffeoyl-O-α-rhamnopyranosyl)-β-glucopyrano]-5-O-β-glucopyranoside and pelargonidin-3-O-[6-O-(4-O-E-p-coumaroyl-O-α-rhamnopyranosyl)-β-glucopyrano]-5-O-β-glucopyranoside.

Keywords:

• Nesaea crassicaulis
• Lobelia cardinalis
• leaves
• UV-Vis
• LC-MS ⁿ
• NMR
• anthocyanins
• flavonoids

Acknowledgements

This project was supported by the Carlsberg Foundation (grant 04-0463/10) and by grant 272-06-0564 from the Danish Natural Science Research Council. Branka Mozetič Vodopivec was supported under a Danish – Slovenian bilateral agreement financed by the Slovenian Ministry of Education, Science and Sport and the Slovenian Research Agency (2006–2007). We thank Tropica A/S for supplying the plants and Rita Buch, Annette Christensen and Dr Wei Zhang for experimental help.