Micromorphology of trichomes and composition of essential oil of Teucrium capitatum

Abstract

The morphology and distribution of the glandular trichomes of Teucrium capitatum L., as well as the chemical composition of the essential oils, were studied. Important differences were found with regard to the major constituents of the essential oils of five populations of T. capitatum grown in Portugal. The oil isolated from one population was characterized by a high content of oxygenated monoterpenes (33.0%), isomenthone (7.7%) being the major constituent. Another oil from a population collected from the same region was dominated by monoterpene and sesquiterpene hydrocarbons (43.9% and 23.2%, respectively), α α α α α-pinene (7.7%), sabinene (11.2%) and β β β β β-pinene (10.3%) being the main compounds. The oils from the other three populations were characterized by a high content of both sesquiterpene hydrocarbons (23.0%, 32.2% and 33.2%) and oxygenated sesquiterpenes (39.7%, 23.4% and 20.4%). T-cadinol (24.1%) and α α α α α-cadinol (9.8%) were the major compounds in the oil from one population, whereas δ δ δ δ δ-cadinene (7.5% and 9.8%) and E-caryophyllene (5.4%) or α α α α α-muurolol (6.0%) were the major constituents in the other samples. The indumentum of the vegetative and reproductive ograns from the five populations of T. capitatum, observed under scanning electron microscopy, showed the same type and distribution of glandular and non-glandular trichomes. Since the ecological and edaphic features of the collecting sites were quite similar, the chemical polymorphism observed seems to be due to genetic factors.

Compositions of Essential Oils and Trichomes of Teucrium chamaedrys L. subsp. trapezunticumRech. fil. and subsp. syspirense (C. Koch) Rech. fil.

“…Based on studies carried out with Salvia blepharophylla, Brandegee ex Epling, Bisio et al [26] suggested two possible ways of release of secreted material: a) breakage of the cuticle; or b) via pores in the cuticle. As we could not observe any cuticle rupture on either peltate or capitate hairs, it seems plausible that the secretion release via cuticle pores may operate in the glandular hairs of our samples as T. capitatum L. [15]. After cuticule rupture in capitate hairs, the glandular head cell assumes a cup shape (Fig., 6 and 12), the type of hairs which has been reported for other species of Teucrium [3] [15] [16].…”

“…chamaedrys (16.7%), T. pestalozzae (13.8%), T. sandrasicum (27.9%), T. montanum (5.8%), and T. antitauricum (28.2%), and b-caryophyllene from T. chamaedrys subsp. lydium (19.7%), T. orientale (21.7%), T. pestalozzae (27.6%), and T. sandrasicum (9.1%) have been reported [15] [16] [23 -25].…”

“…The essential oil content varies (0.5 -1.5%) in different species growing in different parts of the world, and the percentage of the major chemical constituents (mainly monoterpene/sesquiterpene hydrocarbons and oxygenated sesquiterpenes) invariably differ from species to species [4] [5] [7] [12] [15] [16] [22 -25].…”

Chemical Composition and Antimicrobial Activities of the Essential Oils ofTeucrium chamaedrys. subsp.chamaedrys.,T. orientale. var.puberulens., andT. chamaedrys. subsp.lydium.

“…, T. orientale L. var. orientale (Javidnia & Miri, 2003;Yildirim et al, 2004), T. chamaedrys (Morteza-Semnani et al, 2005), T. capitatum L. (Antunes et al, 2004), T. libanitis Schreb. and T. turredanum Losa and Rivas Goday (Blazquez et al, 2003), T. divaricatum Heldr.…”

Teucrium francoi M. Seq., Capelo, J.C. Costa & R. Jardim, a new species of Teucrium gr. scorodonia (Lamiceae) from Madeira

“…The abaxial lamina ( Fig. 2D) is covered with sessile glands [B1 and B2 types; or Types I and II according to the denomination proposed by Antunes & Sevinate-Pinto (1991), or capitate and peltate according to Antunes et al (2004)] and long glandular spreading hairs (slightly antrorse) on the veins [not referred to by Antunes & Sevinate-Pinto (1991) for T. scorodonia plants; also not included in the description given by Navarro & El Oualidi (1997) for any of the species of Teucrium section scorodonia; also not referred to by Servettaz, Pinetti & Bini Maleci (1994) for T. siculum]. These long glandular hairs are of types A1, A2, and A3.…”