Glandular trichomes and the yolatiles obtained by steam distillation of quercus robur leaves

Abstract

G landular trichomes in form of long stretched tubes are present on the lower leaf side of Quercus robur as shown by scanning electron microscopy. The glands contain an essential oil, which was isolated by steam distillation together with volatile waxy com ponents of the leaves in an am ount of 0.025% of fresh leaves. The product of steam distillation was analyzed by GC-MS. Identification of com pounds is based on comparison of their mass spectral data with those of authentic samples in com bination with retention indices and MS data using the SeKoMS (Search Kovats Indices and Mass Spectra) Library. A ltogether 184 com ponents of the product of steam distillation were separated, 155 of which could be identified, another 7 were tentatively assigned. Three groups of substances according to their chemical composition are found: hexenyl derivatives and some acetals (32%); terpenes including m onoterpenes (4%), sesquiterpenes and diterpenes (21%); and alkane derivatives (35%). The residual 8% consist of benzyl alcohol, com pounds which stem from the degradation of carotenes, and miscellaneous constituents. © 1993, Walter de Gruyter. All rights reserved.