The composition and antibacterial activity of essential oils in three Ocimum species growing in Romania

In this study the glandular hair morphology, chemical composition and antimicrobial activity of the essential oils from three Ocimum species have been investigated (Ocimum basilicum L. var. Genovese, O. gratissimum and O. tenuiflorum). The indumentum shows little variation among the investigated species with both glandular and non-glandular hairs presents. Glandular hairs on the three species are peltate and capitate (with various cell numbers in the stalk and gland). The samples of essential oils obtained from the plant aerial organs by hydrodistillation have been analyzed by GC-MS. Linalool (65.38%, 74.22%, 38.60%), eugenol (5.26%, 3.47%, 10.20%) and tau-cadinol (8.18%, 3.47%, 10.20%) appear as the main components in Ocimum basilicum L. var. Genovese, O. gratissimum and O. tenuiflorum. The oils also contain lower levels of α-bergamotene, 1,8-cineole, germacrene D, β-ocimene, α-caryophyllene, camphor, and α-guaiene. All essential oils showed antibacterial activity against Staphylococcus aureus and Escherichia coli depending on their concentration. Ocimum basilicum L. var. Genovese oil produced the strongest antibacterial effect on S. aureus and E. coli.     

The Essential Oils and Glandular Hairs in Different Chemotypes of Origanum vulgare L.

Leaves and flowers of four chemotypes of Origanum vulgare L.were examined for the main components of their essential oiland for the types and distribution of their glandular hairs.Two varieties have high phenol content, one thymol and the othercarvacrol, in their essential oils; one has a moderate thymolcontent and the fourth has a low phenol content and a high alcoholcontent. The percentage of essential oil and the number of peltatehairs were higher in the flowers than in the leaves, the highestbeing in the flowers of a chemotype with a high phenol (thymol)concentration. While there were no differences in structureof the peltate and two types of capitate hairs between chemotypes,the density of the peltate hairs varied and appeared to be correlatedwith the total essential oil content. Origanum vulgare L., essential oils, glandular hairs     

Anti-herbivore structures of Paulownia tomentosa: morphology, distribution, chemical constituents and changes during shoot and leaf development

Background and Aims: Recent studies have shown that small structures on plant surfacesserve ecological functions such as resistance against herbivores.The morphology, distribution, chemical composition and changesduring shoot and leaf development of such small structures wereexamined on Paulownia tomentosa. Methods: The morphology and distribution of the structures were studiedunder light microscopy, and their chemical composition was analysedusing thin-layer chromatography and high-performance liquidchromatography. To further investigate the function of thesestructures, several simple field experiments and observationswere also conducted. Key Results: Three types of small structures on P. tomentosa were investigated:bowl-shaped organs, glandular hairs and dendritic trichomes.The bowl-shaped organs were densely aggregated on the leavesnear flower buds and were determined to be extrafloral nectarines(EFNs) that secrete sugar and attract ants. Nectar productionof these organs was increased by artificial damage to the leaves,suggesting an anti-herbivore function through symbiosis withants. Glandular hairs were found on the surfaces of young and/orreproductive organs. Glandular hairs on leaves, stems and flowerssecreted mucilage containing glycerides and trapped small insects.Secretions from glandular hairs on flowers and immature fruitscontained flavonoids, which may provide protection against someherbivores. Yellow dendritic trichomes on the adaxial side ofleaves also contained flavonoids identical to those secretedby the glandular hairs on fruits and flowers. Three specialtypes of leaves, which differed from the standard leaves inshape, size and identity of small structures, developed nearyoung shoot tips or young flower buds. The density of smallstructures on these leaf types was higher than on standard leaves,suggesting that these leaf types may be specialized to protectyoung leaves or reproductive organs. Changes in the small structuresduring leaf development suggested that leaves of P. tomentosaare primarily protected by glandular hairs and dendritic trichomesat young stages and by the EFNs at mature stages. Conclusions: The results indicate that P. tomentosa protects young and/orreproductive organs from herbivores through the distributionand allocation of small structures, the nature of which dependson the developmental stage of leaves and shoots.     

Glandular Trichomes in Satureja thymbra Leaves

The leaves of the aromatic plant Satureja thymbra have numerousglandular trichomes of two morphologically distinct types glandularhairs and glandular scales Investigations of the anatomy ofthese glandular trichomes with serial thick sections revealedthat the glandular hairs consist of three cells a foot, stalkand head cell Glandular scales also have a unicellular footand stalk Their heads, however, are composed of 12 cells Fourof these cells are small, occupying the central region of thehead, whereas the remainder are large and peripherally arrangedMorphometric analysis showed that, in leaf surface view, glandularscales are about 17-fold larger than glandular hairs In addition,glandular scales were found to occupy 5 7 % of the entire leafsurface area In each glandular scale the total amount of essentialoil, contained within both the subcuticular space and the interiorof the secretory cells, was calculated to be 2 51 x 10^–4mm³ The volume of the essential oil produced by all glandularscales on a single mature leaf was correspondingly determinedto be 0.059 mm³ Finally, the theoretical essential oil yieldof 100 g dry leaves of S thymbra was estimated to be 3 54 %(secretory activity of glandular scales only) Satureja thymbra, glandular trichomes, morphology, morphometry     

Effects of three AM fungi on growth, distribution of glandular hairs, and essential oil production in Ocimum basilicum L. var. Genovese

The essential oils of basil are widely used in the cosmetic, pharmaceutical, food, and flavoring industries. Little is known about the potential of arbuscular mycorrhizal (AM) fungi to affect their production in this aromatic plant. The effects of colonization by three AM fungi, Glomus mosseae BEG 12, Gigaspora margarita BEG 34, and Gigaspora rosea BEG 9 on shoot and root biomass, abundance of glandular hairs, and essential oil yield of Ocimum basilicum L. var. Genovese were studied. Plant P content was analyzed in the various treatments and no differences were observed. The AM fungi induced various modifications in the considered parameters, but only Gi. rosea significantly affected all of them in comparison to control plants or the other fungal treatments. It significantly increased biomass, root branching and length, and the total amount of essential oil (especially α-terpineol). Increased oil yield was associated to a significantly larger number of peltate glandular trichomes (main sites of essential oil synthesis) in the basal and central leaf zones. Furthermore, Gi. margarita and Gi. rosea increased the percentage of eugenol and reduced linalool yield. Results showed that different fungi can induce different effects in the same plant and that the essential oil yield can be modulated according to the colonizing AM fungus.     

Toxic and deterrent effects of two volatile oils against cowpea weevil,Callosobruchus chinensis (Coleoptera: Bruchidae)

The fumigant effect of Mentha piperita and Ocimum basilicum oils and their mixture against adults and eggs of Callosobruchus chinensis (L.) was evaluated. Bioassay experiments showed that Ocimum basilicum oil was significantly effective against adult and egg stage which was the least effective. However, in the fumigant toxicity experiments against adult stage, Ocimum basilicum oil at a dose of 1.0 μl/38.5 ml air caused 100% mortality (LC₅₀ = 1.88), the mixture of both oils at a dose of 6.0 μl/38.5 ml air caused 100% mortality (LC₅₀ = 10.3) and Mentha piperita oil at a dose of 80.0 μl/38.5 ml air caused 80.0% mortality (LC₅₀ = 41.224) during a one day exposure period. Regarding the oviposition deterrent activity, Ocimum basilicum oil achieved 100% oviposition deterrent (at a dose of 0.5 μl/38.5 ml air) followed by the mixture of Mentha piperita and Ocimum basilicum oils, which achieved 71.22% oviposition deterrent (at a dose of 1.0 μl/38.5 ml air) and Mentha piperita oil, which achieved 39.6% oviposition deterrent (at a dose of 5.0 μl/38.5 ml air). The essential oils and their mixtures studied here determined a significant decrease in the number of eggs hatched and in the emergence of adults. The eggs failed to hatch on using Ocimum basilicum oil at a dose of 0.6 μl/38.5 ml air. However, the number of eggs hatched decreased to 7.4 on using a mixture of oils at a dose of 2.0 μl/38.5 ml air and 14.0 with Mentha piperita oil at a dose of 80.0 μl/38.5 ml air compared with 25.0 eggs hatched in the control experiments. On the other hand, the percentage reduction in emerging adults were 100% for Ocimum basilicum oil, 90.9% for a mixture of the two oils and 72.7% for Mentha piperita oil. Results showed that Ocimum basilicum oil and Ocimum basilicum oils plus Mentha piperita oils in blend are potential alternatives to synthetic fumigants in the treatment of durable agricultural products. Successful adoption of plant oils in the protection of food commodities promises an eco-friendly option compatible with international biosafety regulations.     

Ficus carica L. leaf anatomy: Trichomes and solid inclusions

Ficus carica L., a typical plant of the Mediterranean environment, presents leaves covered by an extensive indumentum, and a mesophyll full of solid inclusions. The morphology and ultrastructure of the trichomes, calcium carbonate cystoliths and silicified structures of leaves of F. carica cv Dottato were investigated with light, confocal, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. At the same time, histochemical reactions were also employed to analyse the indumentum composed by glandular and non-glandular trichomes by applying chemical reagents and fluorescence microscopy. Non-glandular and glandular trichomes, capitate, are described. Non-glandular trichomes are unicellular simple, spine-like and present different morphology and sizes. The capitate glandular trichomes are present on leaf adaxial and abaxial surface and consist of one-celled stalk and 3/4 cells spherical head. Histochemical characterisation of leaf hairs revealed the presence of flavonoids, while glandular trichome head cells showed a complex mixture of alkaloids, essential oil and flavonoids. Cu and Al were found in the constitutive structures, spike and dome, of the cystoliths. Several epidermal cells and non-glandular trichomes were silicified. Leaf hairs, trichomes secretions, solid inclusions and silicification of F. carica leaf have significant roles to play in relation to leaf protection from external factors, including high-intensity radiation, herbivores or pathogens.     

Efficient Preparation of Browning-Free Glandular Trichome Tissues from the Surface of Leaves of Rosa rugosa Thunb.

An improved technique for separation of glandular trichomesfrom leaves of rugosa rose (Rosa rugosa Thunb.) was developed.The glandular hairs that had been tightly attached to the tissueof leaf veins via rigid cells were efficiently detached by shakingwith quartz sand dispersed in a solution of mannitol and sodiumascorbate. The mixture of the glandular and simple trichomessuspended in the separation solution was collected by filtrationover nylon mesh (150 mesh), and then it was centrifuged in asolution that contained glycerol. The glandular trichome tips,which were not susceptible to browning, were used for preliminarystudies of cell-free conversions of sesquiterpenes. The glandulartrichomes were found to be a potential source of enzymes associatedwith the biosynthesis and/or bioconversion of sesquiterpenesof R. rugosa. (Received July 28, 1994; Accepted November 11, 1994)     

东北桤木叶表皮盾状腺毛的形态及其变化过程

利用电镜扫描技术,观察东北桤木叶片表面,发现其远轴面表皮上具有盾状腺毛。其由2个基细胞、4个柄细胞和20～25个头部细胞组成,随着分泌物质的积累,细胞逐渐破裂。幼叶远轴面表皮无盾状腺毛,仅有气孔分布。观察东北桤木叶片横切面,发现其为异面叶,远轴面表皮上的盾状腺毛细胞与叶脉维管组织相连。外文资料显示用于表述桤木属表皮上的盾状腺毛的名词较多,该毛状体应为“Peltate glandular hairs”。同时建议对“Glandular scales”、“Peltate gland”、“Peltate scale”、“Peltate glandular hairs”等名词进行规范统一。另外有关东北桤木叶表皮上毛状体从原表皮细胞的发生过程及其分泌物的成份,需进一步研究。     

Structural and Histochemical Investigation of the Glandular Trichomes of Salvia aurea L. Leaves, and Chemical Analysis of the Essential Oil

Anatomical and histological investigations of the secretoryhairs ofSalvia aurea leaves, and identification of the maincomponents of the essential oil were carried out. Two typesof glandular trichome were found: peltate glands, characterizedby a short stalk and a large six to eight-celled head, and capitatetrichomes which were further subdivided into two kinds, thefirst with a short monocellular stalk and two-cellular head(type I), and the second with a multicellular stalk, a neckcell and a small globose unicellular head (type II). Whereaspeltate glands and type I capitate trichomes were always present,type II capitate glands were not found in all leaf samples.The histochemical study suggested an ‘endodermal’role for the stalk cell (peltate and capitate type I) as wellas for the neck cell (capitate type II), preventing the lossof essential oil. Histological reactions also revealed the complexnature of the material secreted by all types ofS. aurea trichome,including polysaccharides, polyphenols and proteins, in additionto the essential oil. Qualitative and quantitative GC-MS analysisof the essential oil revealed camphor to be the main constituent.The findings are discussed in relation to studies of trichomesfrom other members of the Lamiaceae. Salvia aurea L.; glandular trichomes; histochemistry; essential oil     

Leaf Growth in Cotton (Gossypium hirsutum L.) 1. Growth in Area of Main-stem and Sympodial Leaves

A model is presented for growth of individual and successivemain-stem leaves of cotton, based on a series of indoor experimentsand data sets from the literature. Three variable parametersare used to describe individual leaf growth: relative growthrate of meristematic tissue (R¹), relative rate of approachof final area (R₂) and a ‘position parameter’ (t_0.5)which governs the transition from meristematic to extensiongrowth. Final area of a leaf does not occur in the model asa deterministic quantity but it is a result of the processesduring growth. The model generates successive mainstem leavesand sympodial leaves as an integrated system. Assimilate shortagesoccurring in the plant operate on R₁ leading to the characteristicchange of final leaf area along the mainstem. Gossypium hirsutumL., cotton, leaf growth, relative growth rate, meristematic tissue, extension growth, mathematical model     

臭椿不同发育阶段叶片表面结构特征

利用光学显微镜和扫描电子显微镜技术,对臭椿(Ailanthus altissima(Mill.)Swingle)叶片从叶芽到成熟叶4个发育阶段(叶芽、幼叶、近成熟叶和成熟叶)的4种叶表面结构(表皮毛、气孔器、角质层、腺体)进行了详细地观察和比较。结果显示:叶片上、下表面具单细胞非腺毛和头状腺毛两种表皮毛,其密度在叶芽阶段最大,之后随着叶片的生长和展开表皮毛密度逐渐降低;气孔器主要分布于下表面,叶片近成熟时气孔器密度最大;角质层具有条纹状结构,其隆起程度在近成熟叶阶段达到最大;叶片基部两侧具锯齿状突起,每个突起上有一个腺体,腺体发育成熟后可分泌透明黏液。说明叶片表面各结构特征是臭椿对环境长期适应的结果。     

Chemotaxonomic Analysis of the Aroma Compounds in Essential Oils of Two Different Ocimum basilicum L. Varieties from Iran

Hydrodistilled essential oils of 21 accessions of Ocimum basilicum L. belonging to two different varieties (var. purpurascens and var. dianatnejadii) from Iran were characterized by GC‐FID and GC/MS analyses. The oil yield was found to be between 0.6 and 1.1% (v/w). In total, 49 compounds, accounting for 96.6–99.7% of the oil compositions, were identified. Aromatic compounds, represented mainly by methyl chavicol (33.6–49.1%), and oxygenated monoterpenes, represented by linalool (14.4–39.3%), were the main components in all essential oils. Monoterpene hydrocarbons were present in the essential oils of all accessions of the purpurascens variety, whereas they were completely absent in those of the dianatnejadii variety, indicating that monoterpene hydrocarbons might be considered as marker constituents of the purpurascens variety. The chemotaxonomic value of the essential‐oil compositions was discussed according to the results of the cluster analysis (CA). The CA showed a clear separation of the O. basilicum var. purpurascens accessions and the O. basilicum var. dianatnejadii accessions, although the data showed no major chemotype variation between the studied varieties. Indeed, the CA revealed only one principal chemotype (methyl chavicol/linalool) for both varieties. In conclusion, GC/MS analyses in combination with CA showed to be a flexible and reliable method for the characterization of the chemical profiles of different varieties of Ocimum basilicum L.     

Nematicidal Principles from Two Species of Lamiaceae

Aqueous extracts of Ocimum sanctum and O. basilicum leaves contained compounds that killed Meloidogyne incognita larvae in 160 min. Thin layer and gas-liquid chromatography, and infrared spectrophotometry indicated that the essential oils eugenol and linalool were the active nematicidal compounds.     

Density-dependent Mortality Induced by Low Nutrient Status of the Substrate

The hypothesis that changing the fertility level of the substratewould change the self-thinning line (different slope or intercept)followed by high-density populations was tested by sowing populationsof Ocimum basilicum L. at two densities on a soil-based pottingmix adjusted to three fertility levels (F0, F1 and F2). Fertilitylevel significantly affected the slope of the thinning linesfor both shoot and root biomass. For shoot biomass, more mortalityoccurred per unit increase in biomass as fertility level declined(the slope of the thinning line became flatter). The slope ofthe log shoot biomassvs. log density relationship was -0.5 atthe F2-, zero at the F1-, and 0.94 at the F0-fertility. Forthe log root biomassvs. log density lines, slopes were zeroat the F2- and F0-fertility levels, and -0.32 at F1. Packingof shoot biomass into canopies of individual plants correlatedwell with observed exponents of self-thinning lines at the F2-and F1-fertility level. Plants at the F2-fertility level requiredmore canopy space to support a given shoot biomass than plantsat F1, indicating that shoot competition was more intense atthe F2-fertility level for a given biomass. Leaf area indexand size inequality also increased with fertility level fora given shoot biomass. Density-dependent mortality in populationsgrown at the F0-fertility level was highly unusual in havinga positive slope for the shoot biomass vs. density relationship.Shoot growth per plant was static as density declined in theF0-populations; however, root growth per plant increased. Allmeasurements of shoot growth (mass, height, canopy extension,leaf area) remained static in the F0-populations: root massand length increased in comparison. It is argued that root competitionbecame sufficiently intense to cause the density-dependent mortalityseen at the F0-fertility level, with little contribution ofshoot competition to mortality. Copyright 1999 Annals of BotanyCompany Ocimum basilicum, self-thinning, root competition, shoot competition, fertility level and competition, density-dependent mortality, allometric self-thinning.     

Bicyclosesquiphellandrene and 1-epibicyclosesquiphellandrene: Two new dienes based on the cadalene skeleton

Two new sesquiterpene hydrocarbons, bicyclosesquiphellandrene and 1-epibicyclosesquiphellandrene have been isolated from Piper cubeba oil and Ocimum basilicum oil respectively. Their structures were elucidated spectroscopically and their stereochemistry by acid rearrangement and hydrogenation studies.     

Effects of two sodium salts on fatty acid and essential oil composition of basil (Ocimum basilicum L.) leaves

The effects of two sodium salts on growth, fatty acids, and essential oil compositions were investigated in a medicinal and aromatic plant, Ocimum basilicum cultivated in hydroponic medium. Plants were subjected to an equimolar concentration of Na₂SO₄ (25 mM) and NaCl (50 mM) for 15 days. Our results showed that leaf growth rate was more depressed by 25 mM Na₂SO₄ than by 50 mM NaCl. The total fatty acid contents did not show any change in plants. α-Linolenic, palmitic, and linoleic acids were the major fatty acids. The identification of basil leaf fatty acids has not been previously studied and this work revealed the predominance of polyunsaturated fatty acids. Under both salts, leaf fatty acid composition remained unchanged. Regarding the essential oil yield, it decreased significantly by 28 % under 25 mM Na₂SO₄ and showed an increase by 27 % under 50 mM NaCl. The major volatile compound in leaves was linalool with 34.3 % of total essential oil constituents, followed by eugenol (19.8 %), 1.8-cineole (14.4 %) and methyl eugenol (5.2 %). Further, levels of eugenol and methyl eugenol were most modulated by salt, and the negative correlation between these two compounds reflects the stimulation of O-methyltransferase activity under both salts.     

Salinity-induced changes in essential oil,pigments and salts accumulation in sweet basil (Ocimum basilicum) in relation to alterations of morphological development

The objective of the project was to study salinity-induced effects on essential oil, pigments and salts accumulation in sweet basil (Ocimum basilicum, the cultivar Perrie) in relation to the alteration of plant morphological development and yield production. Hydroponically grown plants were exposed to one of six NaCl concentrations (1, 25, 50, 75, 100 and 130 mM NaCl). Inhibitory effects of salinity on biomass production of the shoot and the root, and area of individual leaves were apparent already under cultivation with 25 mM NaCl. Elevation of salinity from 1 to 100 mM NaCl induced 63% and 61% reductions in fresh and dry herb biomass production, respectively. The stress-induced reduction of foliage biomass sourced mainly from inhibition of leaf area development rather than reduction of internode and leaf number. Cl and Na concentrations in the leaves, stems and roots increased with elevation of NaCl concentration in the cultivation solution. While the extent of Cl accumulation was leaves>stems>roots, Na was largely excluded from the leaves and was preferentially accumulated in roots and the stems, potentially accounting for the moderate sensitivity of the leaf tissue to salinity. Salt stress increased the contents of essential oil and carotenoids in the leaves that may further account for the moderate sensitivity of sweet basil to salinity and suggest a potential for agro-industrial production. A twofold increase in both carotenoid concentration and the percent of essential oil in the fresh tissue was observed by elevation of the salinity from 1 to 130 mM NaCl. Overall, the stress induced increase of the percent of essential oil in the tissue in the salinity range 1–75 mM NaCl was about 50%, and thereby compensated for the similar reduction of biomass production in this salinity range, so that oil production on per plant basis was not reduced by salinity.     

Glandular Hair Formation in Origanum Species

Eleven Origanum species were investigated in this study. Inall these species, leaf glandular hairs have the same structureand they have been found to follow a common developmental pattern.They originate from a single protodermal cell which dividessuccessively parallel to leaf surface to give rise to the footcell, the stalk cell and the mother cell of the head. The latterundergoes a series of symmetric and asymmetric anticlinal divisionsresulting in a 12-celled head (four small cells in the centreand eight large cells peripherally arranged). Determinationof the glandular scale morphology within the Lamiaceae generaand further comparison between the various gland types wouldbe helpful to systematics. Origanum species, Lamiaceae, glandular hair, development     

不同品种来源广藿香叶表皮毛特征比较分析

叶表皮毛特征作为药用植物的"微性状"特征,被越来越多地应用于植物学分类研究中,表皮毛的生长发育状态可以直接影响药材的整体品质。广藿香主要含有挥发油成分,叶表皮毛中的腺毛是其挥发油的主要合成分泌场所,而非腺毛可以起到保护作用,影响其长势和产量。为了探讨叶表皮毛特征在广藿香品种鉴别方面的意义,该研究以8个不同品种来源以及2个采收期(6月末和10月末)的广藿香的顶叶、第4对生叶及底叶为材料,采用水合氯醛透化法制片,于光学显微镜下观察拍照,使用Microsoft Excel 2019统计数据,采用SPSS 23.0统计学软件对叶表皮毛密度、腺毛直径进行方差分析、主成分分析和聚类分析。结果表明:同一品种来源,不同采收期的广藿香叶表皮毛密度有显著性差异,6月末采收的广藿香叶表皮毛密度显著低于10月末采收的;根据叶表皮毛(非腺毛、头状腺毛、盾状腺毛)密度及腺毛直径,可将相同采收期的8个不同品种来源广藿香分为4类,且可以将已知品种来源的南香、肇香和牌香分开,与传统分类结果有着很好的一致性。叶表皮毛密度和腺毛直径在广藿香的分类中具有一定的参考意义,并为广藿香药材品质形成机制的研究提供参考。