Disentangling the chemistry of Australian plant exudates from a unique historical collection

Abstract

Significance For millennia, Aboriginal Australian peoples have used the extraordinary physicochemical properties of plant exudates from practical applications to cultural expression. We employ state-of-the-art spectroscopy to characterize the molecular compositions of well-preserved, native Australian plant exudates ( Xanthorrhoea , Callitris , Eucalyptus , and Acacia ) from a historic collection assembled over a century ago. This work demonstrates the benefits of X-ray Raman spectroscopy for the analysis of these complex natural systems. It provides key information for a broader understanding of their terpenoid, aromatic, phenolic, and polysaccharide composition and subsequent chemical classification. It complements Fourier-transform infrared and pyrolysis–gas chromatography–mass spectrometry by allowing bulk-sensitive analysis in a fully noninvasive manner and probes molecular features which remain silent in these commonly employed analyses.