NMR-Based Metabolic Profiling ofAnigozanthosFloral Nectar

Abstract

Nuclear magnetic resonance spectroscopic methods have been used to characterize the chemical composition of floral nectar of Anigozanthos species with a minimum of sample preparation and without derivatization. The nectar of this passerine-pollinated plant is largely dominated by glucose and fructose, while sucrose occurs only at a minor level. Tyrosine, several additional amino acids, and a variety of carboxylic acids were identified and their concentrations estimated. A linear diarylheptanoid was detected as a trace component, marking the first time this type of secondary product in Hemodoraceae has been found.

Nectar formation and floral nectary anatomy of Anigozanthos flavidus: a combined magnetic resonance imaging and spectroscopy study

“…Invertase-catalysed hydrolysis of sucrose seems to be responsible for the ratio of hexoses to sucrose ( Nicolson and Fleming, 2003 ) in the nectar. However, the simple action of invertase should result in a glucose-to-fructose ratio of 1:1, which is not always the case ( Baker et al , 1998 ; Chalcoff et al , 2006 ; Wolff, 2006 ; Hölscher et al , 2008 ). Hence, additional enzymes and transporters must be involved in generating the chemical composition of nectars.…”

“…The nectar composition of many plants has been studied for more than 50 years using various chromatographic and spectroscopic techniques. In a recent study, nuclear magnetic resonance (NMR) spectroscopy was used for metabolic profiling of Anigozanthos floral nectar ( Hölscher et al , 2008 ). 13 C NMR was used to determine the major carbohydrates quantitatively, which in this nectar are glucose and fructose.…”

“…Sucrose, which usually is one of the major sugars in nectar, was detected in low concentrations, together with other minor nectar components such as amino acids only by using the much more sensitive 1 H NMR spectroscopy. In addition to the very low sucrose level, interestingly, the Anigozanthos floral nectar was found to contain glucose and fructose in a ratio of 1.2:1.0 ( Hölscher et al , 2008 ).…”

The biosynthetic origin of oxygen functions in phenylphenalenones of Anigozanthos preissii inferred from NMR- and HRMS-based isotopologue analysis

“…In this context, special structural requirements for the phenylphenalenone precursor, which undergoes the putative intramolecular Diels-Alder reaction, have been discussed (Schmitt and Schneider, 1999;Schmitt et al, 2000;Hölscher et al, 2008). For cycloaddition, a linear diarylheptanoid skeleton possessing a suitable diene/dienophile combination in its structure is essential.…”

Sugar Preferences of Avian Nectarivores Are Correlated with Intestinal Sucrase Activity

“…Because the foraging records for T. haematodus in Western Australia (Brown et al 1997) were rather limited (as a result of their recent introduction in the 1960s and subsequent establishment as a pest species in Perth, Western Australia), detailed foraging records for T. haematodus were also compiled from the Queensland-New South Wales border region (Cannon 1984). Nectar compositions of Australian plants were compiled from published and unpublished sources (Baker and Baker 1982;Paton 1982;Gottsberger et al 1984;McFarland 1985;Nicolson 1994;Davis 1997;Baker et al 1998;Nicolson and Van Wyk 1998;Hölscher et al 2008;Morrant et al 2010; S. W. Nicolson and B.-E. Van Wyk, unpublished data). The ratio of hexoses to sucrose was calculated as , and nectars H/(H) ϩ S were classed as hexose dominant (10.8), hexose rich (0.6-0.8), mixed (0.4-0.6), sucrose rich (0.2-0.4), or sucrose dominant (!0.2).…”