Composition of the essential oils and in vivo emission of volatiles of four Lamium species from Italy: L. purpureum, L. hybridum, L. bifidum and L. amplexicaule

The essential oils and the volatiles emitted in vivo by flowers, leaves and bracts of Lamium purpureum, L. hybridum, L. bifidum, L. amplexicaule (Lamiaceae) were analyzed by GC-MS and SPME, respectively. All the essential oils were characterized by their high contents of germacrene D. In L. purpureum (35.4%), L. hybridum (39.0%) and L. bifidum (34.9%), it was the main compound, while in L. amplexicaule (28.9%), the main constituent was trans-chrysanthenyl acetate (41.1%). The SPME analyses showed a pattern typical of volatiles for both the different species and the single plant parts analyzed.