Qualitative and Quantitative Secondary Metabolite Profiles in a Large Set of Sumatra Benzoin Samples

Abstract

Sumatra benzoin, a resin produced by Styrax benzoin and Styrax paralleloneurum, is used as an aromatic agent and may have the potential to be developed as a new agricultural fungicide. In this context, we performed a comprehensive metabolite profiling of a commercial grade A resin by high-performance liquid chromatography coupled with photodiode array detection, evaporative light scattering detection, and mass spectrometry (HPLC-PDA-ELSD-MS) analysis in combination with 1 H NMR. Thirteen compounds including a new cinnamic acid ester containing two p-coumaroyl residues were identified after preparative isolation. These compounds accounted for an estimated 90% of the crude resin according to 1 H NMR analysis. The two major constituents, p-coumaryl cinnamate (5) and sumaresinolic acid (11), were quantified by HPLC analysis. In a next step, the chemical profiles and the content in p-coumaryl cinnamate were compared in a large set of resin samples of different quality grades that were obtained from various commercial suppliers in Sumatra. The qualitative profiles of the samples were very similar, but significant quantitative differences were observed between different quality grades and origins of the samples for the relative contents.