Comparative Study of the Volatile Components of Fresh and Fermented Flowers of Alnus sieboldiana (Betulaceae)

Abstract

Analysis of the volatile components present in the fresh male and female flowers and young leaves shows that 2-phenylethanol is the major component in all these three organs, which play a significant role in the strong resinous aromatic odor. The male flowers contained styrene as a second major compound. The level of styrene does not affect the male flowers odor concentration. The level of β-phenylethyl cinnamate and trans-methyl cinnamate in the fermented male flowers decreased as the fermentation time increased. This was due to the Penicillium enzymatic action on the fermented male flowers.

Constituents of Fermented Male Flowers of Alnus sieboldiana (Betulaceae)

“…Compound 7 may be produced from pinocembrin (6), which is a known constituent of the male flowers of A. sieboldiana In conclusion, fermentation of A. sieboldiana male flowers by the white fungus Penicillium sp. caused hydroxylation at positions 3 and 3' of naringenin (3) to produce 4 and 5, while methylation at positions 5 and 7 of pinocembrin (6) gave 7.…”

“…[5], causing the powerful aromatic odor of both male and female flowers to diminish dramatically and finally turn unpleasant. The powerful aromatic odor was due to the presence of 2-phenylethanol [6].…”

“…may be produced from pinocembrin(6), which is a known constituent of the male flowers of A. sieboldiana [4c], through methylation by plant-O-methyltransferases (OMTs) [11c]. Compound 7 is converted to compound 8 by flavanone 3hydroxylase (E3)[11d].…”