Volatile constituents of different organs of Psoralea bituminosa L.

The essential oil and SPME samples of the leaves, flowers and seeds of Psoralea bituminosa L. were analysed by GC and GC-MS. We have investigated also the presence of monoterpene or aliphatic alcohol glucosides. The essential oils showed both qualitative and quantitative differences. The main constituents of the leaf and the flower essential oils were caryophyllene (23% and 18%, respectively), beta-farnesene (15% and 6%, respectively), and germacrene D (24% and 18%, respectively). Significant amounts (7%) of the same compounds were also directed in the seed essential oil, but tricyclene (11%) and alpha-pinene (50%) were the most important constituents of this oil. The volatile fractions of remaining leaf aqueous extracts after treatment with beta-glucosidase revealed qualitative differences in comparison with the composition of the corresponding essential oils, and high levels of 3-hexen-1-ol (37%) and 1-octen-3-ol (27%) were observed. The SPME analysis of the fresh leaves, flowers and seeds of P. bituminosa confirmed the qualitative composition of the volatile oils, even if we detected significative differences in the percentage ratio between monoterpenes and sesquiterpenes in comparison with the oils, where sesquiterpenes were the main components. In fact the variation of the monoterpenes, tricyclene, alpha-pinene and camphene between the leaf oil and the corresponding headspace sample was remarkable: tricyclene increased from 0.1% to 8%, alpha-pinene from 0.1% to 16% and camphene from 0.3% to 10% in the SPME samples. Copyright (C) 2004 John Wiley Sons, Ltd.