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DOI: 10.1055/s-0030-1265837
Aroma substance of fragrant tree Platycarya strobilacea and change of phenolic constituents on toasting
The wood of Platycarya strobilacea (PSW) is a fragrant tree and has been used as a substitute for expensive agarwood (Aquilaria agallocha). PSW was burned when it is used as fragrant tree, and the aim of our study is characterization of the aroma substance and chemical change of the constituents during the heating. Previously, we reported that PSW contains 3-hydroxy-α-calacorene, oak lactone (syn. whisky lactone) precursor (1), gallotannins, such as pentagalloyl-β-D-glucose, and ellagitannins, such as pedunculagin, 1(β)-O-galloylpedunculagin (5)1,2.
First we demonstrated presence of three new eudesmane-type sesquiterpenoids (2-4), and the structures were elucidated by spectroscopic methods. These terpenoids are detected in the smoke when the PSW was toasted. As for degradation of other phenolic compounds on toasting, ellagitannins are completely disappeared, whereas the gallotannins and oak lactone precursor remained unchanged. On toasting, gallic acid and ellagic acid increased, and m-digallate, sinapylaldehyde, coniferylaldehyde, vanillin, and 3'-O-methylellagic acid 4-O-(4'-O-galloyl)-xyloside (6) were newly generated.
References: 1. Tanaka, T., et al. (1996)J. Nat. Prod. 59: 997–999.
2. Tanaka, T., et al. (1998) Phytochemistry 47: 851–854.