Analytical investigation of styrax and benzoin balsams by HPLC- PAD-fluorimetry and GC-MS

An HPLC and GC study has been conducted on the aromatic oleoresins styrax and benzoin produced by several American, Mediterranean and East-Asian trees, and widely used in ancient civilisations for their therapeutic and odoriferous properties. Initial experiments were performed by HPLC-PAD-fluorimetry for the analysis of several aromatic components, and then completed by GC-MS for the characterisation of both aromatic and triterpenic derivatives. In this work, it was crucial to isolate from fresh natural exudates, and to characterise by two-dimensional NMR, some of the major constituents in order to extend the standard molecular pool prior to chromatographic identifications. This study reveals coniferyl benzoate as an excellent distinctive fluorescent biomarker of Siam benzoin substrate. It also confirms that fluorimetric-coupled detection is a powerful analytical tool for the identification of compounds in Hamamelidaceae extracts that are almost undetectable by UV. GC-MS was successfully applied to the determination of the botanical origin of Sumatra benzoin, and to the identification of lupeol [3beta-lup-20(29)-en-3-ol] for the first time in such balsam-type materials.