Essential oil composition and glandular trichomes of Marrubium vulgare L. growing wild in Algeria

A scanning electron microscopic (SEM) study of the aerial parts of Marrubium vulgare L. grown wild in Algeria showed a dense woolly indumentum of stellate, nonglandular, point-shaped trichomes that completely hide both the adaxial and abaxial leaf epidermes, as well as the stem and flower surfaces bearing the glandular trichomes. Peltate and two types of capitate trichomes constitute the morphological distinct glandular trichomes that are spread over the vegetative and reproductive organs. The essential oils of M. vulgare were obtained by hydrodistillation and distillation-extraction from the aerial parts collected during the flowering (F) and vegetative phases (V), and analyzed by GC and GC/MS. The essential oils were obtained in a yield of <= 0.05 % (v/w). Eugenol was the main component in the F oil (50%) but comprised only 16% in the V oil. beta-Bisabolene was the dominant component of the V oil (29%) and the second main component in the F oil (11%).