Pharmacy 157 Morphological Features of Romanian

Med. Surg. J. – Rev. Med. Chir. Soc. Med. Nat., Iaşi – 2020 – vol. 124, no. 1 PHARMACY ORIGINAL PAPERS MORPHOLOGICAL FEATURES OF ROMANIAN ENDEMIC TEUCRIUM L. SPECIES Ioana Humulescu1, I. I. Lungu1*, Oana Cioanca1, Alexandra Roxana Sava2, Ioana Buciscanu1, Silvia Robu3, C. Toma2, Monica Hancianu1 “Grigore T. Popa” University of Medicine and Pharmacy Iasi 1. Faculty of Pharmacy, Department of Pharmacognosy “Al. I. Cuza” University Iasi 2. Faculty of Biology, Department of Plant Biology “Dunărea de Jos” University Galati 3. Faculty of Medicine and Pharmacy, Department of Pharmacognosy *Corresponding author. E-mail: [email protected] MORPHOLOGICAL FEATURES OF ROMANIAN ENDEMIC TEUCRIUM L. SPECIES (Abstract): Teucrium is a genus that belongs to Lamiaceae family, but the endemic plants from our country have not been studied before. Therefore, the aim of this study was to pro- vide evidence and specific characteristics with taxonomic value. Material and methods: we collected the plants (Teucrium chamaedrys L., T. montanum L. and T. polium L.) from the wild flora in the Northern Romania and we prepared section and microscopic plates from various organs (stems, branches, leaves and bracts). Results: the observed features were both common and different (quantitatively and qualitatively) between the species. Conclu- sions: we obtained for each species several specific characteristics that allow the proper identification even when the environmental conditions are not optimal for the complete growth of the plants. Keywords: TEUCRIUM, MORPHOLOGY, STEMS, LEAVES, TAX- ONOMY Most species of Lamiaceae are medici- cine, gastronomy, cosmetology (1, 3, 4, 5). nal plants long used in folk medicine Volatile oils are recognized for their known and appreciated for their active powerful anti-antioxidant and antimicrobial principles (α-pinene, β-pinene, limonene properties, while polar compounds such as and menthol isolated from volatile oils and flavonoids, iridoids and diterpenes exert diterpenes, flavonoids and iridoids isolated important anti-inflammatory, antioxidant, from polar fractions) (1). The Romanian anticancer and gastroprotective action. All flora comprises about 33 genera and 130 the justified aspects are the remedies for species and subspecies of the Lamiaceae using such species not only in traditional family (2). At present, this is one of the and modern medicine but also in daily life, most famous and studied families of plants, in the form of nutritious teas, spices or the available data is abundant in chemical flavorings (6, 7, 8). composition with important biological The genus Teucrium has a wide distri- actions, in the most diverse fields: medi- bution in Europe, Asia, America, Australia 157 Ioana Humulescu et al. and especially in the Mediterranean area, proper identification of these species. the latter comprising approximately 96% of the species. In Romania, the genus Teu- MATERIAL AND METHODS crium comprises 5 species and several Plant material subspecies that grow in spontaneous flora. For our study we selected three Roma- Plants are usually perennial, in the form of nian endemic species as follows: Teucrium shrubs or sub-shrubs (2, 9, 10). The repre- chamaedrys L., T. montanum L. and T. sentatives of this genus are appreciated for polium L. The chosen species were very their medicinal properties, both in modern little anatomically researched, which is medicine, proof being the numerous studies why we also addressed this aspect in our performed in the last 40 years, but especial- research. The plants were harvested from ly in traditional medicine. It seems that the the spontaneous flora, of Horlesti (Teu- first information on the beneficial actions crium chamaedrys L. and T. polium) and of these species was recorded by a Trojan Bicaz (T. montanum L.), during 20th and king, Teucrion, after which the plants were 30th of June 2019. also named, and dates back to our era. In Preparation of the microscopic plates traditional medicine, Teucrium species The fresh vegetative organs (leaf and have been used for hundreds of years for stems - the main axis and a lateral branch), their antioxidant, tonic, diaphoretic, anal- were fixed in 70% ethyl alcohol. Prior to gesic, antipyretic, antirheumatic, antiseptic analysis, each sample was cross-sectioned and hypoglycemic (1, 4, 5). Recently, cyto- through and the sections were colored us- toxic and anticancer action has also been ing the double staining method, with ruthe- discovered (6). The remedies obtained from nium red and iodine green (12, 13, 14). The the aerial parts are rich in aromatic com- permanent preparations were made in glyc- pounds with a bitter taste, so that they can erol gelatin and evaluated using the Eu- be used as flavorings or in the form of romex microscope (iScope series with spices, with a beneficial effect on the di- 4x10, 10x10, 20x10, 40x10 lens) and Im- gestive system. age Focus Alpha software. Euromex Although the anatomical structure of the sCMEX- 20 was used for photography of Lamiaceae species has been studied exten- each sample. sively in the 19th and 20th centuries, in works referring only to medicinal plants, RESULTS AND DISCUSSION the species of Teucrium are rarely men- The morphological characteristics ob- tioned; only Cole (1992), referring to the served in our study revealed both common significance of terpenoids, deals extensive- and uncommon elements, especially for T. ly with species of this genus. Nevertheless, montanum as compared to the other two only exotic taxa from the Teucrium genus species. are cited in the available literature. Stem shape and anatomy Therefore, the aim of our research was The cross-section of the stem is round represented by the description of three and somewhat similar for T. montanum and species of Teucrium endemic in Romania T polium. For both samples, the pericycle is (9, 10), trying to find several features of made of bundles of sclerenchymatous and taxonomic importance that would allow the parenchyma cells. However, the stem from 158 Morphological features of Romanian endemic Teucrium L. species T. chamaedrys is square, with the ribs Also, the bark of T. montanum is thicker slightly protruding (fig. 1). (8 layers of cells) than the other two species and presents a thin collenchyma layer outward. The innermost layer of the cortex is primary endoderm, with cells strongly flattened radially and elongated tangential- ly. In the lateral walls, Caspary thickenings are also visible. The epidermis of T. montanum is sub- stantially exfoliated, which is why at the surface of the stem there are few trichomes, located only in the portions where this primary protective tissue persists. On the other hand, the epidermis of Teucrium chamaedrys has isodiametric cells of different size, with thicker internal and external walls, the latter being covered by a thin cuticle; just near the ribs the cuticle is very thick, the cutinization affecting all the thickness of the external wall. From place to place there are visible stomata, which project slightly above the epidermis. At the level of the epidermis, long, multicellular, uniseriate hairs are located, sometimes with arched tip and very short, pluricellular secretory beads (peltate hairs). Regarding the epidermis of T. polium contains isodiametric cells, with the outer wall thicker than the others and covered by the cuticle. Also, there are numerous multicellular trichomes, with the terminal cell much longer than the others and sometimes with a curved tip. The secretory trichomes are rare also multicellular, with a relatively short pedicel and a single or quadruple cell gland. Such elements have been previously noted in various Teucrium species from Serbia and Montenegro. Therefore, our results are in accordance with literature data (1, 8, 9). Another visible difference between the Fig. 1. Cross-sections through the stem of stem sections is noted for T. montanum the investigated samples which presents a very large central cylinder 159 Ioana Humulescu et al. which does not start with a sclerenchymatous layer as in T. polium and T. chamaedrys. Moreover, the vascular bundles are almost entirely of secondary origin. The phloem fibers form a thin ring, made up of sieve tubes, attached cells and many parenchyma cells, whereas the xylem is thick and lignified and presents numerous vessels of different diameter, irregularly dis- persed in the fundamental mass. Among the vessels and the cells of the xylem, there are few cells of lignified wood parenchyma, sometimes arranged in discontinuous radial rows. For further confirmation, we also observed the features on the secondary branches of the same species. The branches contain similar cell layers, but they are thinner and differ from the main stem by the thickness of the sclerenchyma (maxi- mum two layers) and the number of surface hairs. However, at the epidermis level of the secondary stems of T. montanum numerous long, multicellular and small, short secretory trichomes are visible. Moreover, in this case in the central pith, a large lacu- na resulting from the disruption of the central parenchyma is observed. Sometimes this cavity is crossed by 1-2 bands of per- sistent medullary parenchyma (fig. 2). With respect to T. polium main axis, the structure of the secondary branches differs by the following characteristics: the epidermis presents more numerous and longer surface hairs, the glandular tri- Fig. 2. The general aspect of the secondary chomes are rarer and shorter, the collen- branches obtained for the three Teucrium chyma layer is thinner at the hypodermic species level, the cells of the cortical parenchyma are often isodiametric; the sclerenchyma Leaf shape and anatomy pericycle ring is thinner; the phloem and In general, all Teucrium species have pith are thinner, but the primary xylem is the foliar lamina edges curved towards the slightly lignified abaxial face. Both the median vein and the lateral veins of the first order are protuber- 160 Morphological features of Romanian endemic Teucrium L. species ant slightly to the lower face of the lamina.

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