Determination of selenium in Teucrium species by hydride generation atomic absorption spectrometry

Hydride generation atomic absorption spectrometry (HGAAS) was applied for determination of selenium content in dried aerial parts of wild and cultivated Teucrium species (Lamiaceae) growing in Croatia: T. arduini L., T. chamaedrys L., T. flavum L., T. montanum L., T. polium L., and T. scordium L. subsp. scordioides Schreb. Special attention was paid to the wet oxidation procedure for the sample dissolution. The proposed procedure involved microwave-assisted sample digestion using a mixture of HNO3/H2O2. Wild specimens generally had a higher content of selenium, with concentrations of 0.030-0.095 mg/kg of the dry drug. Cultivated plants contained 0.020-0.055 mg Se/kg.     

Antimicrobial activity,total phenolic content and flavonoid concentrations of <Emphasis Type="Italic">Teucrium</Emphasis> species

In vitro antimicrobial activity of 21 crude extracts obtained from seven taxa of the genus Teucrium (T. chamaedrys, T. montanum, T. arduini, T. polium, T. scordium subsp. scordium, T. scordium subsp. scordioides and T. botrys) was tested against bacterial and fungal species. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using a microdilution analysis method. Total phenolic content and flavonoid concentrations were measured spectrophotometrically. Total phenols were determined using Folin-Ciocalteu reagent and their amounts ranged from 28.49 up to 159.84 mg CA/g of extract (chlorogenic acid equivalent). The amounts of flavonoids ranged from 38.17 up to 190.45 mg RU/g of extract (rutin equivalent).The plant extracts showed greater potential of antibacterial than antifungal activity. A relationship was found between total phenolics and biological activity. The highest level of total phenols was measured in the methanol extracts, which demonstrated higher antimicrobial activity than acetone and ethyl acetate extracts. Staphylococcus aureus ATCC 25923 appeared to be the most sensitive organism. Our results indicate that Teucrium spp extracts are rich sources of phenolic compounds and are promising candidates for further development as natural antimicrobial agents.     

Effects of essential oil from Teucrium polium on some digestive enzyme activities of Musca domestica

The essential oil from Teucrium polium was evaluated for its adverse effects on larval instars of Musca domestica . The essential oil was blended with a diet at a concentration that produced 50% mortality of subjected insects (LC₅₀) (80 ppm). To learn about the situation of digestive enzymes of M. domestica treated with the essential oil, third larval instars were dissected under non-active enzyme conditions and their midguts were removed. The supernatant was used as an enzyme source after homogenization and centrifugation of the homogenates. Results revealed that some main digestive enzymes in the larval midgut were adversely affected when exposed to the food-incorporated essential oil. Proteinase extracted from larval midgut hydrolyzed the synthetic substrates B-Arg-pNA, Z-Arg-Arg-PNA and Z-Phe-Arg-PNA for trypsin, cathepsin B and cathepsin L activities, respectively, in control and treated larvae. The essential oil caused a reduction of 61.5% in tryptic activity. Significant 69% and 79% reductions were also observed in cathepsin L and B activities, respectively. Carbohydrase activities of α-amylase, α-glucosidase and β-glucosidase were detected in larval midgut extract. All assayed carbohydrases were affected by the essential oil. The most notable impact, a 93% reduction, was observed in α-amylase. Decreases of 69.5% and 42% were obtained in α-glucosidase and β-glucosidase activity, respectively. This study indicated that the larvicidal effect of the essential oil from Teucrium polium may be due to its detrimental effects on digestive enzymes. It seems that the detrimental effect of the oil can be due to both the inhibitory nature of the oil and the destruction of the midgut epithelium.     

Neo-clerodane diterpenes from Teucrium fruticans

In addition to three out of the four previously reported neo-clerodanes already found in Teucrium fruticans (fruticolone, isofruticolone and 8 beta-hydroxyfruticolone), and 6-acetylteucjaponin B (isolated from T. scordium and T. grisebachii), four new neo-clerodanes, namely 7 beta-hydroxyfruticolone, 11-hydroxyfruticolone, deacetylfruticolone and 6-acetyl-10-hydroxyteucjaponin B were also isolated. The structures were unambiguously elucidated based on extensive NMR spectral studies (one- and two-dimensional experiments). Semi-prep-HPLC proved to be a convenient purification procedure, occasionally being followed by TLC. The new compounds were assayed against Spodoptera littoralis and two of them were shown to have potent antifeedant activity.     

Comparative anatomical and micromorphological studies on Teucrium creticum and Teucrium orientale var. orientale (T. sect. Teucrium, Lamiaceae)

Teucrium creticum L. and T. orientale L. var. orientale are two related taxa in Teucrium sect. Teucrium . In this study, the value of anatomical and micromorphological characters for distinguishing between these two taxa is analysed. Transverse sections of the stem, as well as both transverse and surface sections of the leaves were examined anatomically. According to the data obtained, collenchyma and sclerenchyma do grow more in T. creticum than in T. orientale var. orientale . The leaves of T. creticum are hypostomatic and have a characteristic hypodermis, which is under the upper epidermis, as well as abundant spherocrystals in the upper epidermis. The leaves of T. orientale var. orientale are amphistomatic, yet no spherocristals exists in epidermal cells and the hypodermis is absent. The results obtained from studies carried out under scanning electron microscope (SEM) shows that the nutlet micromorphology varies between the two taxa. In both taxa, the nutlet surfaces are reticulate and glandular. Eglandular hairs do occur. However, in T. orientale var. orientale , 20–60 μm long eglandular hairs with scabrid surface occur only along the margins of the nutlets, whereas the ¾ dorsal sides of the nutlets in T. creticum are all covered with 90–500 μm long, smooth-surfaced hairs. Additionally, while the glandular hairs on the nutlets of T. creticum are subsessile, those on the nutlets of T. orientale var. orientale are capitate and distinctly stalked.     

Amino acids composition of Teucrium nutlet proteins and their systematic significance

BACKGROUND AND AIMS: Plant species are considered as a good source of dietary proteins, although the nutritional quality of proteins depends on their amino acid composition. In this work the protein content and amino acid composition of nutlets of 21 Teucrium taxa (Lamiaceae) from Spain were analysed and their nutritional quality was compared with the minimum values established by the Food and Agriculture Organization of the United Nations (FAO). In addition, the amino acid composition was evaluated as a chemical character to clarify the taxonomic complexity in this genus. METHODS: Amino acid content of nutlets was determined after derivatization with diethyl ethoxymethylenemalonate by high-performance liquid chromatography. Previously, nutlets samples were hydrolysed and incubated in an oven at 110 degrees C for 24 h. KEY RESULTS: The protein content was variable, ranging from 6.4 % in T. dunense to 43.8 % in T. algarbiense. According to the FAO values all taxa contain satisfactory amounts of leucine, threonine and valine and are deficient in lysine. The similarity analysis of Teucrium taxa using amino acid composition data did not clearly reflect the infrageneric classification of this genus. CONCLUSIONS: Annual species, such as T. spinosum, T. aristatum and T. resupinatum showed a better balanced amino acid composition. The dendrogram partly matched with the karyological complexity of Teucrium. No correlation between amino acid composition and habitat has been observed, showing that Teucrium nutlet amino acid composition may not be strongly influenced by the environment.     

Isolation and structure elucidation of three neo-clerodane diterpenes from Teucrium fruticans L. (LABIATAE)

Recently, the isolation from Teucrium fruticans of neo-clerodanes, namely 7beta-hydroxyfruticolone, 11-hydroxyfruticolone, deacetylfruticolone and 6-acetyl-10-hydroxyteucjaponin B, in addition to fruticolone, isofruticolone and 8beta-hydroxyfruticolone (three out of the four previously reported ones), and 6-acetylteucjaponin B (isolated from T. scordium and T. grisebachii) was reported. Minor compounds presumably of neo-clerodane nature were shown by HPLC analysis on a new extract. Three new compounds, difuranofruticol, deoxyfruticolone and 10-hydroxyteucjaponin B, and the known 7,8-didehydrofruticolone were unambiguously elucidated based on extensive NMR spectral studies (one- and two-dimensional experiments). The compounds were assayed for their antifeedant activity against Spodoptera littoralis and for their antifungal activity against Rhizoctonia solani. Compounds 9-11 showed low antifeedant activity and the feeding ratio of 12 was moderate-low. None of the tested compounds displayed significant activity against R. solani.     

Enhancement of single cell oil production by Yarrowia lipolytica growing in the presence of Teucrium polium L. aqueous extract

Yarrowia lipolytica, grown in a nitrogen-limited continuous culture (D = 0.032 h^–1), produced 9.3 g dry biomass l^–1, which contained 0.25 g oil g^–1. When an aqueous extract from Teucrium polium L. was added, the biomass concentration remained constant while the oil content increased to 0.33 g oil g^–1 dry weight. The specific rate of oil formation increased from 7.9 to 10.6 mg oil g^–1 biomass h.     

Chemical diversity of volatiles of Teucrium orientale L. var. orientale, var. puberulens, and var. glabrescens determined by simultaneous GC-FID and GC/MS techniques

In the present work, three varieties of Teucrium orientale, var. orientale, var. puberulens, and var. glabrescens, were collected and investigated for chemical composition of the oils. Subsequent gas chromatography (GC-FID) and gas chromatography coupled to mass spectrometry (GC/MS) revealed high abundance of sesquiterpenes in the essential oils analyzed. All the oils contained β-caryophyllene (22.6, 8.5, and 6.3%, resp.) and hexadecanoic acid (7.9, 12.8, and 13.1%). Germacrene D (24.6 and 33.4%) and bicyclogermacrene (6.7 and 8.5%) were found to be the main constituents of var. orientale and var. puberulens, respectively. The high percentages of β-cubebene (26.9%), α-cubebene (9.0%), and α-copaene (7.2%) established the diversity of var. glabrescens. The qualitative difference between the essential oils allowed the differentiation between the varieties in agreement with the morphological observations described in Flora of Turkey for each variety studied. In addition, a cluster analysis of twelve Teucrium taxa based on the essential-oil composition has been carried out. Hovewer, the analysis did not clearly reflect the infrageneric classification of the genus, it largely confirmed the relationships between the infraspecific taxa of Teucrium orientale and T. chamaedrys.     

Chemical Diversity of Volatiles of Teucrium orientale L. var. orientale,var. puberulens,and var. glabrescens Determined by Simultaneous GC‐FID and GC/MS Techniques

In the present work, three varieties of Teucrium orientale, var. orientale, var. puberulens, and var. glabrescens, were collected and investigated for chemical composition of the oils. Subsequent gas chromatography (GC‐FID) and gas chromatography coupled to mass spectrometry (GC/MS) revealed high abundance of sesquiterpenes in the essential oils analyzed. All the oils contained β‐caryophyllene (22.6, 8.5, and 6.3%, resp.) and hexadecanoic acid (7.9, 12.8, and 13.1%). Germacrene D (24.6 and 33.4%) and bicyclogermacrene (6.7 and 8.5%) were found to be the main constituents of var. orientale and var. puberulens, respectively. The high percentages of β‐cubebene (26.9%), α‐cubebene (9.0%), and α‐copaene (7.2%) established the diversity of var. glabrescens. The qualitative difference between the essential oils allowed the differentiation between the varieties in agreement with the morphological observations described in Flora of Turkey for each variety studied. In addition, a cluster analysis of twelve Teucrium taxa based on the essential‐oil composition has been carried out. Hovewer, the analysis did not clearly reflect the infrageneric classification of the genus, it largely confirmed the relationships between the infraspecific taxa of Teucrium orientale and T. chamaedrys.     

Post-tetanic Potentiation and Depression in Hippocampal Neurons in a Rat Model of Alzheimer’s Disease: Effects of Teucrium Polium Extract

Neurophysiology - The plant Teucrium polium (T.p.) possesses a wide range of pharmacological activities due to the presence, in particular, of different phytochemicals, phenols and flavonoids. We...     

Chemotaxonomic value of the essential oil compounds in species of Teucrium pumilum aggregate

Volatile compounds from the aerial parts of Teucrium lepicephalum Pau and Teucrium carolipaui C. Vicioso ex Pau, both belonging to the Teucrium pumilum aggregate, were analysed by capillary GC and GC-MS. From the common and specific compounds (mono- and sesquiterpenes) of the two taxa, chemical characterization was carried out and taxonomic relationships were assessed. Application of the cluster and k-means discriminant analysis shows a differential chemical relationship between T. lepicephalum and Teucrium carolipaui.     

Chemotaxonomic Importance of the Essential‐Oil Composition in Two Subspecies of Teucrium stocksianum Boiss. from Iran

The hydrodistilled essential oils obtained from aerial flowering parts of Teucrium stocksianum ssp. stocksianum (TSS) and T. stocksianum ssp. gabrielae (TSG) from Iran were analyzed by capillary GC and GC/MS. The oil analysis of two subspecies led to the identification of 65 compounds that accounted for 93.3 and 95.1% of the total oil compositions, respectively. Sesquiterpenoids (52.9%) constituted the main compounds in the essential oil of TSS represented mainly by cis‐sesquisabinene hydrate (12.0%), followed by epi‐β‐bisabolol (6.6%), guaiol (5.4%), and β‐eudesmol (4.4%), whilst monoterpenoids (61.2%) were found to be the major components of the oil of TSG, represented by α‐pinene (23.0%), β‐pinene (13.0%), myrcene (6.3%), and sabinene (6.3%). The principal component in both subspecies, TSS and TSG, was α‐pinene (22.0 and 23.0%, resp.) and β‐pinene (6.5 and 13.0%, resp.). epi‐α‐Cadinol, myrcene, and sabinene, which were detected as principal compounds of TSG, were characterized in lower amounts (<1.5%) in the oil of TSS. Seven components were identified in the oil of TSS corresponding to 25.9% of total oil, which were totally absent in the oil of TSG, of which cis‐sesquisabinene hydrate (12.0%), guaiol (5.4%), and β‐eudesmol (4.4%) were in considerable amounts. Taxonomic position of the subspecies is discussed on the basis of phytochemical data.     

Micromorphological and Phytochemical Research on Teucrium scorodonia and Teucrium siculum from the Italian Flora

Micromorphology and distribution of trichomes in different plant parts of Teucrium scorodonia and Teucrium siculum from five populations in Italy are described. The composition of volatile compounds in the same plants has also been studied. The micro-morphological characters of the two taxa differ only in the calyces. T. siculum from the Euganean hills shows a great shape variability in the bracts. As far as the volatile compounds are concerned, this taxon reveals a somewhat special position, particularly for the presence of monoterpenes, which are lacking in T. siculum from Central and Southern Italy.     

Variation of volatiles in Tunisian populations of Teucrium polium L. (Lamiaceae)

Volatiles from wild Tunisian diploid (2n=2x=26) and tetraploid (2n=4x=52) Teucrium polium L. populations from five bioclimatic zones were assessed by GC and GC/MS. Thirty-eight compounds were identified. Main volatiles at the species level were myrcene (6; 15.3%), germacrene D (27; 9.0%), alpha-pinene (6.6%), beta-pinene (3; 5.8%), and alpha-cadinol (38; 5.1%). A significant variation among populations was observed. The tetraploid populations belonging to the sub humid and lower semi arid bioclimates showed a high amount of myrcene (6; 24.2-43.8%), those from the upper arid contain high percentages of alpha-cadinol (38; 50.6%). The dominant compounds in diploid populations, mainly located in the semi arid zone, are alpha-pinene (1) and germacrene D (27). Population chemical structure, assessed by a principal component analysis (PCA) using all identified compounds, is concordant with bioclimate and ploidy level. In situ conservation of populations should be made appropriately according to these two factors.     

Biological activities of Teucrium flavum L., Teucrium fruticans L., and Teucrium siculum rafin crude extracts

The genus Teucrium (Lamiaceae) includes 300 species widespread all around the world, which are perennial herbs or shrubs commonly, named germanders. In Italy, Teucrium flavum L., Teucrium fruticans L., and Teucrium siculum Rafin are mostly present in Liguria, Sicily, and Sardegna. Teucrium species are characterized by mono and sesquiterpene hydrocarbons, flavonoids, fatty acid esters, and essential oils. Many species of this genus show antioxidant, antimicrobial, and antifungal activities, rendering them useful as natural preservative ingredients. In view of the interesting biological properties reported for Teucrium spp., in this study we determined the total phenol and flavonoid content of inflorescence extracts of T. flavum L., T. fruticans L., and T. siculum Rafin. In addition, we investigated the in vitro antioxidant and antibacterial activities of inflorescence extracts against pathogenic bacteria. Obtained results demonstrated that extracts had in vitro antioxidant activity and showed antimicrobial ability against Gram-positive and Gram-negative strains albeit with different effectiveness probably due to the different qualitative/quantitative composition of the extract also suggesting that these extracts might be useful in preventing several diseases in which oxidative stress may represent an important pathogenic mechanism.     

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

The species formerly recognized as Teucrium scorodonia in Madeira is here described as new: Teucrium francoi M. Seq., Capelo, J.C. Costa & R. Jardim. Morphologically close to species of Teucrium gr. scorodonia [ T. scorodonia L., T. pseudoscorodonia Desf., T. siculum (Raf.) Guss. and T. kotschyanum Poech], it exhibits, nonetheless, some distinct diagnostic characters. The indumentum density and type of hairs of T. francoi are clearly distinct from those of related species, as are the shape and dimensions of the leaves and bracts, calyx, and corolla, which are all taken as taxonomically significant diagnostic features. A diagnosis and a distribution map are presented for this new species. Morphology, ecology, biogeography, and conservation issues are discussed. Teucrium francoi , which is an endemic from Madeira (Portugal), is to be found mostly in the scope of the association Teucrio francoi–Origanetum virentis J.C. Costa, Capelo, Jardim, Sequeira, Lousã & Rivas-Martínez, but also occurs in somewhat humid habitats, such as open stands of Rosa mandonii Déségl. associated with small streams.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 639–647.     

Taxonomic reinstatement of Teucrium andrusi from T. paederotoides based on morphological and anatomical evidences

Teucrium andrusi, described by Post from Mardin province, Turkey, was synonimized with T. paederotoides in the flora of Turkey. According to the records in the flora of Turkey T. paederotoides was a steno‐endemic species, only known from the type locality in Gaziantep and from Mardin province. Specimens of T. paederotoides s.l. were collected from both localities and a detailed comparison of the plants from Gaziantep with those from Mardin revealed that the two populations were sufficiently distinct from each other to be recognised as separate species. Thus, T. andrusi Post is reinstated from the synonymy with T. paederotoides. Teucrium andrusi is morphologically different from T. paederotoides s.s. in terms of its general indumentum, leaf margin, bract and calyx shape, corolla colour and nutlet macro–micromorphology. It can be anatomically distinguished from T. paederotoides s.s. by stoma type, stomatal distribution on the leaf surface, crystal content in the cells and cuticula thickness. Ecological data related with the accompanying species also support species status for T. andrusi. While the two taxa are very similar in pollen and nutlet morphology, trichome density on the nutlets are different.     

Effect of a Teucrium polium L. extract on the growth and fatty acid composition of Saccharomyces cerevisiae and Yarrowia lipolytica

Aqueous Teucrium polium extract slightly inhibits the growth of Saccharomyces cerevisiae (K_i=0.029 [g/l]^-1) and Yarrovia lipolytica (K_i=0.061 [g/l]^-1). However, this extract causes important changes in the unsaturation degree (/mol) of the cellular lipids. It moreover favours the increase of the linolenic acid concentration and the decrease of the oleic one in both species.     

Chemotaxonomic Significance of the Terpene Composition in Natural Populations of Pinus nigra J.F.Arnold from Serbia

The essential‐oil variability in seven native populations belonging to different infraspecific taxa of Pinus nigra (ssp. nigra, var. gocensis, ssp. pallasiana, and var. banatica) growing wild in Serbia was analyzed. In the needles of 195 trees from seven populations, 58 essential‐oil components were identified. The major components were α‐pinene (43.6%) and germacrene D (29.8%), comprising together 73.4% of the total oil composition. Based on the average chemical profile of the main terpene components (with contents >5%), the studied populations were found to be the most similar to populations from central Italy and Greece (ssp. nigra). Cluster analysis showed the division of the populations into three principal groups: the first group consisted of Populations I, II, III, IV, and V (considered as ssp. nigra group), the second of Population VI (ssp. pallasiana group), and the third of Population VII, which had the most distinct oil composition (ssp. banatica group). The taxonomic implications of the essential‐oil profiles of the investigated taxa of this very complex species are discussed.