Nobilis Plants Research Articles

The effect of the Laurus nobilis plant on two types of fungi that cause human diseases

The study was carried out to assess the quantity of one plant, Laurus nobilis for their as medicine and their microbial effects. Plant samples were collected in Autumn 2017 from Al-Jabal Al-Akhdar in Libya.
 The extracts were screened for their biological activities against fungi strains Penicillium notatum and Aspirgillus niger .
 The results showed that anti fungal activity did not effect on Penicillium notatum and Aspirgillus niger.

Experimental induction of resins as a tool to understand variability in ambers

Abstract. Amber is chiefly known as a preservational medium of biological inclusions, but it is itself a chemofossil, comprised of fossilised plant resin. The chemistry of today's resins has been long investigated as a means of understanding the botanical sources of ambers. However, little is known about the chemical variability of resins and consequently about that of the ambers that are derived from particular resins. We undertook experimental resin production in Araucariacean plants to clarify how much natural resin variability is present in two species, Agathis australis and Wollemia nobilis, and whether different resin exudation stimuli types can be chemically identified and differentiated. The latter were tested on the plants, and the resin exudates were collected and investigated with Fourier-transform infrared attenuated total reflection (FTIR-ATR) spectroscopy to give an overview of their chemistry for comparisons, including multivariate analyses. The Araucariacean resins tested did not show distinct chemical signatures linked to a particular resin-inducing treatment. Nonetheless, we did detect two separate groupings of the treatments for Agathis, in which the branch removal treatment and mimicked insect-boring treatment-derived resin spectra were more different from the resin spectra derived from other treatments. This appears linked to the lower resin viscosities observed in the branch- and insect-treatment-derived resins. However the resins, no matter the treatment, could be distinguished from both species. The effect of genetic variation was also considered using the same stimuli on both the seed-grown A. australis derived from wild-collected populations and on clonally derived W. nobilis plants with natural minimal genetic diversity. The variability in the resin chemistries collected did reflect the genetic variability of the source plant. We suggest that this natural variability needs to be taken into account when testing resin and amber chemistries in the future.

EVALUATION OF CHRYSOPERLA CARNEA COMPLEX AND COCCINELLID PREDATORS AS BIOCONTROL AGENTS OF RICANIA SPECULUM (WALKER, 1851) (HEMIPTERA RICANIIDAE)

Ricania speculum is an alien insect feeding on several host plants belonging to several families, including important vegetables, crops, ornamental plants, wild plants as well as trees. For the first time, recently, Chrysoperla sp. and coccinellid beetles have been observed preying on this species in the field on Citrus sp. and Laurus nobilis plants. The main purposes of this work were to evaluate the possible predation capability of these groups of insects and determine their prey preference in laboratory trials. In the choice trials, R. speculum nymphs were paired in a confined space and exposed for 24h to single predators: Ch. carnea complex and to the coccinellids Cryptolaemus montrouzieri, Adalia bipunctata, Coccinella septempunctata, and Propylea quatuordecimpunctata. Specimens of Aphis rumicis, an aphid frequently found on her baceous plants, were used as a control prey. In the cage trials, a single Ch. carnea complex second-instar larva was placed into a jar containing a tomato plant with ten R. speculum nymphs. In the choice trials, a high mortality percentage of both preys was observed with the Ch. carnea complex, while in those with Coccinellids only high A. rumicis mortality was reported. In the cage trials, 13% mortality of R. speculm was recorded after 24h while after 72h and 168h prey mortalities reached 18% and 25%, respectively. The results of the study showed that larvae of the Ch. carnea complex could be potential predators of R. speculum, while coccinellids do not seem promising predators of this alien species.

Structural, optical and electrical studies of Bi2S3 nanoparticles and their impact on the superconducting properties of (Bi,Pb)2Sr2Ca2Cu3Oδ ceramics

Bi2S3 nanoparticles were synthesized by the green chemistry process via Laurus nobilis plant extract as a stabilizing agent. Structure and crystallite size were investigated by X-ray diffraction. The average particle size was explored by transmission electron microscopy. Optical properties were carried out using UV–Visible diffuse reflectance spectroscopy. Electrical properties were performed using complex impedance spectroscopy. The effect of Bi2S3 nanoparticles on the superconducting properties of bismuth-based compound ((Bi,Pb)2Sr2Ca2Cu3Oδ) was reported. It was found that Bi2S3 nanoparticles exhibit an orthorhombic structure with an average particle size of 30 nm, and a band gap of 1.73 eV. Furthermore, the inclusion of a suitable amount of Bi2S3 nanoparticles into the (Bi,Pb)2Sr2Ca2Cu3Oδ superconducting compound is an efficient route for improving the superconducting performances.

An Endemic Plant of Cyprus, Origanum majorana: Is It A New Alternative Natural Product for Malaria Treatment?

Malaria still remains to be a public health threat and one of the most important infectious diseases to get attention from World Health Organization. No domestic malaria cases have been reported on the island of Cyprus since 1948, as a result of successful elimination process. All of the malaria cases detected in recent years are imported cases. As known, hundreds of medicines are obtained from plants and traditional medicine are used in endemic places of malaria. The cause of malaria - Plasmodium parasites, are developing resistance to antimalarial drugs. Hence, research on plant extracts and essential oils have gained great interest in recent years to obtain new and safe agents/substances. In our study, it was aimed to investigate the in vivo antimalarial activities of essential oils obtained from Origanum dubium, Origanum majorana, Salvia fruticosa and Laurus nobilis plants which grows in Northern Cyprus against Plasmodium berghei - the rodent malaria agent. Plants were collected in appropriate seasons and were dried to obtain and analyze essential oils via Clevenger Apparatus system. L929 mouse fibroblast cell line and MTT [3-(4.5-dimethylthiazole-2-yl) -2.5-diphenyltetrazolium bromide] kit were used to determine the cytotoxic activities of the essential oils obtained. In our study, total of 36 mice (Balb/c) of 6 groups (6 mice in each group) were formed: chloroquine group (CG) (50 mg/kg) as malaria reference group, untreated control group (UTCG), O.dubium (OD) (20 mg/kg), O.majorana (OM) (20 mg/kg), S.fruticosa (SF) (20 mg/kg) and L.nobilis (LN) (20 mg/kg). The essential oils were given to mice infected with P.berghei strain orally on 0, 1, 2 and 3rd days (4 times in total). Blood was taken from the tail end of each mouse 24 hours after the last treatment and blood collection was continued every two days until the mice died. Withdrawn blood taken from the mice were prepared as a thin smear and stained with Giemsa. Then, parasitemia percentages in each smear were calculated. As a result of the cytotoxicity tests, cytotoxic activity was not found at 100 µg/ml (20 mg/kg) in all oils except OD essential oil. While the mice receiving chloroquine continued their lives with the disappearance of the parasite on the 6thday, the mice in the UTCG died on the 9th day. The parasitemia rate reached 35% in the OM group on the 23rd day, in the OD group on the 21st day and in the other groups (SF and LN) on the 14th day and the mice have died. In our study, the difference between the life span in all groups was found statistically significant (p≤ 0.001). As a result, the essential oils O.majorana (14 days increase according to UTCG) an endemic plant of Cyprus and O.dubium (12 days increase according to UTCG) which had an antimalarial effect, decreased parasitemia and increased the life span of mice more than two times, indicated that they could be a source for the acquisition of new antimalarial molecules.

Facile green synthesis of zinc oxide nanoparticles (ZnO NPs): antibacterial and photocatalytic activities

The objective of this study was carried out to exhibit a novel, cost-effective, non-toxic and green way to prepare ZnO nanoparticles (NPs) using Laurus nobilis plant extract as both reducing and capping agents without any hazardous material. X-ray diffraction analysis also confirmed that the synthesized NPs has Wurtzite hexagonal structure with an average crystalline size between 20 and 35 nm. The extract was found to contain reducing components such as polyphenols (22.5%) and flavonoids (21%). The ZnO NPs was characterized by a peak 375 nm in the UV- Vis spectrum. In addition, FTIR results provided the presence of both, leaf extract and ZnO NPs. The antibacterial activity of ZnO NPs was investigated against Escherichia coli using an agar dilution method. The minimal inhibitory concentration value of the ZnO nanoparticles was found to be 1200 μg ml−1 for E. coli. As a result, the biosynthesized ZnO NPs indicated a great promise for applications in a large area of biomedical applications as a kind of antibacterial material. The biosynthesized ZnO NPs also conducted successful photocatalytic activity as much as commercial ZnO powders under the UV light using the textile dye, Remazol Brilliant Red F3B (Reactive Red 180 (RR180)) solutions. We found an excellent degradation percentage (99%) within a short time (60 min). Plant extract was suggested as an essential bioresource of producing ZnO NPs.

Determination of the Essential Oil Composition and the Antifungal Activities of Bilberry (Vaccinium myrtillus L.) and Bay Laurel (Laurus nobilis L.)

This study aimed to determine the composition andthe antifungal activity of the essential oils of Vaccinium myrtillus and Laurus nobilis plants. In the study, 22 components were identified in the essential oil of V. myrtillus, which represented 100% of the total essential oils. Accordingly, 1,8-cineole (41.07%), β-Linalool (12.72%), α-Pinene (12.17%) and Myrtenol (6.48%) were determined as the main components of the essential oil of V. myrtillus. The essential oil of L. nobilis consisted of 39 compounds and 1,8-cineole (50.68%), α-Terpinyl acetate (14.19%), 4-Terpinenol (4.07%) and α-Terpineol (2.90%) were determined as the main components, which represented 100% of the total essential oils. In the trials, doses of 0 (control) 1, 2, 4, 8 and 10 μL/petri dish were used. V. myrtillus essential oil inhibited mycelial growth in Sclerotinia sclerotiorum (Lib.), Alternaria solani, Fusarium oxysporum f. sp. radicis-lycopersici (Sacc.) W.C. Synder & H.N. Hans (FORL) and and Verticillium dahliae Kleb by 61.38%, 100%, 80.36% and 57.91% respectively. Bay laurel essential oil at 10 μL/petri dish dose inhibited the mycelial growth of A. solani, S. sclerotiorum, (FORL) by 100%, whereas it inhibited the mycelial growth in V. dahliae by 61.23%. Study results showed that V. myrtillus and L. nobilis essential oils have strong antifungal activities.

In vitro antibacterial activity of several plant extracts and essential oils against Brucella melitensis

Summary Medicinal plants are considered to be new resources for the production of agents that could act as alternatives to antibiotics in the treatment of antibiotic-resistant bacteria. The aim of this study was to evaluate the efficacy of some plants native to Syria in the treatment of brucellosis. In vitro activities of some essential oils and plant extracts of some medicinal plants against 89 Brucella melitensis isolates was determined by disc diffusion method at a concentration of 5%. The microdilution assay in the fluid medium was used to determine the MICs of essential oils and plant extracts. Among the evaluated herbs, only Thymus syriacus and Cinnamomum zeylanicum essential oils and Laurus nobilis plant extract showed a high activity against B. melitensis strains. Thus, minimal inhibitory concentration (MIC50) values for T. syriacus, C. zeylanicum, and L. nobilis against B. melitensis were 6.25, 3.125 and 6.25 μl/ml, respectively. Among studied essential oils and plant extracts, T. syriacus and C. zeylanicum essential oils, and L. nobilis plant extract were the most effective ones. Moreover, T. syriacus - C. zeylanicum combination was more effective than use of each of them alone. Then, T. syriacus and C. zeylanicum essential oils and L. nobilis plant extract could act as bactericidal agents against B. melitensis.

First Report of Calonectria ilicicola Causing a New Disease on Laurus (Laurus nobilis) in Europe

AbstractCrown and root rot has been detected on potted Laurus nobilis plants in a nursery located in the Catania province (Italy). Perithecia referable to a Calonectria species were consistently detected on crowns and stems of symptomatic plants. Based on morphology, cultural features and molecular analysis, the species was identified as Calonectria ilicicola. Koch’s postulates were fulfilled by pathogenicity tests carried out on potted Laurus nobilis seedlings. To our knowledge, this is the first report of the occurrence of a disease caused by Ca. ilicicola on Laurus nobilis.

Water Deficit Stress Responses of Three Native Australian Ornamental Herbaceous Wildflower Species for Water-wise Landscapes

Perennial wildflower species are important but not well-understood elements in water-wise landscaping that anchors urban water conservation programs in arid climates. Comparative growth and physiological responses to soil substrate drying of three herbaceous Australian ornamental species from habitats of variable moisture regimes were investigated in the context of isohydric and anisohydric behavior. Clonal Orthosiphon aristatus, Dianella revoluta ‘Breeze’, and Ptilotus nobilis plants were container-grown individually and competitively together in two separate studies. In both studies, plants were water-stressed through cyclical dry downs. We measured stomatal conductance (g S), soil water content, and water potential during each study and osmotic adjustment estimated from pressure-volume data and plant biomass at the end of each study. O. aristatus, a rainforest species, fit a general anisohydric model of high water use and more negative water potential during soil drying until stomatal closure and leaf wilting. D. revolata and P. nobilis, indigenous to Australia's dry interior, fit a general isohydric, drought-tolerant model of stomatal closure from water deficits that moderates leaf water potential but through different mechanisms. P. nobilis and D. revolata moderate water use and maintain acceptable aesthetic performance under water stress, suitable for mixed low-water landscape plantings. O. aristatus would not be suitable for low-water urban landscapes, either isolated or in mixed plantings, because of high soil water depletion and wilting.

Starch-to-sugar conversion in wood parenchyma of field-growing Laurus nobilis plants: a component of the signal pathway for embolism repair?

The ability of stems of Laurus nobilis (L.) to refill embolised xylem conduits was studied in plants both at optimal water supply (W) and under conditions of soil drought inducing xylem pressures (Px) of -1.54 (S1) and -2.35 MPa (S2). Starch depolymerisation in wood parenchyma was measured as percentage of cells 'with high starch content' (HSC-cells) counted under a microscope. HSC-cells decreased during embolism and increased again in refilled stems. A direct relationship was found between percentage of HSC-cells and Px, with HSC-cells between 65 and 75% of the total at Px ≥ -0.6 MPa, at which recovery from PLC was recorded. At low transpiration, starch re-appeared in wood parenchyma cells but only in plants that showed diurnal stomatal opening (W- and S1-plants). In S2-plants showing diurnal stomatal closure and nocturnal opening with Px between -1.2 to -2.4 MPa, HSC-cells were only 25% and plants did not recover from PLC. This finding suggests that (i) the Px threshold for embolism repair was ≥ -0.6 MPa, and (ii) impeded phloem loading limits starch content in wood parenchyma and embolism repair. We conclude that starch depolymerisation acts as a signal to phloem unloading sugars to embolised conduits thus generating the necessary osmotic gradients driving refilling.

Evaluation of key horticultural traits for Ptilotus nobilis in sub-tropical regions

Plants belonging to the genus Ptilotus have immense potential to be developed for the floricultural industry. Many of these plants flower profusely and have potential as cut focal flowers, cut fillers, potted colour or for use in landscape design. Ptilotus nobilis plants produce numerous fragrant cream to pink coloured inflorescences, which exhibit a long vase-life adding to their value as a cut-flower crop. As yet, there is no information published on the key horticultural traits for this species. This work undertook greenhouse trials to evaluate the floricultural attributes for P. nobilis collected from the Cunnamulla region in western Queensland, Australia. As a potted colour crop, P. nobilis may be marketed as a short lived perennial with plants flowering continuously for more than 2 years. From a cut-flower perspective, each plant produced an average of 11 flowering stems per month during December to April, and 8 flowering stems per month during May to August. Flowering stem length and inflorescence length averaged 35.4 and 7.2 cm, respectively for the period November to April, versus 39.2 and 6.3 cm stem and inflorescence lengths, respectively during May to August. As flowering stem lengths range from 17 to 79 cm, there is scope for selection of tall forms for cut flowers and compact forms for potted colour. Furthermore, the harvest duration of flowering stems averaged 43.5 days highlighting the durability of P. nobilis as a cut-flower product. A minimum thermal requirement of 623 growing degree days (GDD) were required to reach flowering after pruning with a predicted base temperature of 0.5 °C and maximum temperature of 18.2 °C when grown in a greenhouse at Gatton, Queensland, Australia. Further work needs to investigate the flowering physiology in response to temperature, photoperiod and light intensity to determine whether flowering can be predicted for different production regions. Also, vegetative propagation methods and field cultural requirements require further investigation to progress the commercial development of this new product.

Gas Chromatography/Mass Spectrometry Analysis of Laurus nobilis Essential Oil Composition of Northern Cyprus

The chemical composition of the essential oil isolated from the leaves of the Laurus nobilis plant (from the Northern Cyprus Mountains) by hydrodistillation was analyzed by gas chromatography-mass spectrometry. Of the 81 compounds representing 98.74% of total oil, monocyclic monoterpenes such as 1,8-cineole (58.59%), alpha-terpinyl acetate (8.82%), and terpinene-4-ol (4.25%) were the main components. Bicyclic monoterpenes such as alpha- and beta- pinene (3.39-3.25%) and sabinene (3.32%) were also identified. The acyclic monoterpenes linalool (0.19%) and myrcenol (0.10%) were present in smaller amounts, and so were the sesquiterpenes. o-Cymene (1.30%) and p-cymene (1.83%) were the main, while cumin aldehyde (0.24%), dimethylstyrene (0.08%), eugenol (0.16%), methyl eugenol (0.05%), and carvacrol (0.05%) were found as minor, aromatic compounds of laurel oil.

First Report of Leaf Spots on Laurus nobilis Caused by Phytophthora citricola in Belgium.

Laurus nobilis (laurel tree) is used as an herbal and ornamental tree in gardens in Belgium. During the summer of 2001, a serious outbreak of leaf spots was observed in some Belgian nurseries. Symptoms were large, irregular, brown leaf spots located primarily on the distal half of leaves and delimited by a black margin. As the disease progressed, the spots enlarged, coalesced, and finally led to leaf withering. The isolated fungus had morphological characteristics typical of Phytophthora citricola. On potato dextrose agar (PDA) it formed white, entire rosette colonies. Within 1 week, semipapillate sporangia were found abundantly in water at room temperature. They were mostly ovoid and highly variable in size (20 to 82 × 12 to 48 µm). The sporangial apex was broadly papillate. Oogonia were spherical (18 to 38 µm in diameter), and the antheridia were paragynous. Pathogenicity of the isolated fungus was confirmed by inoculating two visibly healthy L. nobilis plants. Five leaves per plant were wounded by a scalpel, subsequently inoculated with 5-mm-diameter mycelial plugs on PDA, and sealed with Parafilm. As a control, noncolonized agar plugs were placed on wounded leaves from a third L. nobilis plant. The inoculated plants and the control plant were kept for 1 day under a plastic cover (approximately 95% relative humidity) on the laboratory bench. Within 1 week, all inoculated leaves developed symptoms, whereas the control leaves remained symptomless. P. citricola was sucessfully re-isolated, satisfying Koch's postulates. The pathogen was also characterized using molecular tools. The ribosomal DNA regions, ITS1 and 5.8S rDNA-ITS2, were sequenced and highest similarity scores were obtained with corresponding Phytophthora citricola sequence regions (>99% identity for both sequences). The new GenBank Accession Nos. are AY525786 (ITS1) and AY525787 (5.8S rDNA-ITS2). On the basis of the symptoms, cultural and morphological characteristics, and positive results in pathogenicity and PCR tests, the isolate was considered to be P. citricola. To our knowledge, this is the first record of P. citricola on leaves of L. nobilis in Belgium.

Axillary Meristems and the Development of Epicormic Buds in Wollemi Pine (Wollemia nobilis)

Intact trees of Wollemia nobilis Jones, Hill and Allen (Araucariaceae) routinely develop multiple coppice shoots as well as orthotropic epicormic shoots that become replacement or additional leaders. As these are unusual architectural features for the Araucariaceae, an investigation was made of the axillary meristems of the main stem and their role in the production of epicormic and possibly coppice shoots. Leaf axils, excised from the apex to the base of 2-m-high W. nobilis plants (seedling origin, ex situ grown), were examined anatomically. Small, endogenous, undifferentiated (no leaf primordia, no vascular or provascular connections) meristems were found in the axils from near the shoot apex. In the more proximal positions about half the meristems sampled did not differentiate further, but became tangentially elongated to compensate for increases in stem diameter. In the remaining axils the meristems slowly developed into bud primordia, although these buds usually developed few leaf primordia and their apical 'domes' were wide and flat. Associated vascular development was generally restricted to provascular dedifferentiation of the cortical parenchyma, with the procambium usually forming a 'closed loop' that did not extend back to the secondary vascular tissues. Development of the meristems was very uneven with adjacent axils often at widely differing stages of development into buds. The study shows that, unlike most conifers, W. nobilis possesses long-lived meristematic potential in most, if not all, leaf axils. Unlike other araucarias that have been investigated, many of the meristems in the orthotropic main stem will slowly develop into bud primordia beneath the bark in intact plants. It appears likely that this slow but continued development provides a ready source of additional or replacement leaders and thus new branches and leaves.

Limits to xylem refilling under negative pressure in Laurus nobilis and Acer negundo

ABSTRACTThe ability of juvenile Laurus nobilis and Acer negundo plants to refill embolized xylem vessels was tested under conditions of soil drought when xylem sap pressure was substantially negative, thus violating the expected condition that pressure must rise to near atmospheric for refilling. Intact potted plants were dried to a stem water potential (ΣW) corresponding with approximately 80% loss of hydraulic conductivity (PLC) in shoots. Then plants were re‐watered and kept at a less negative target ΨW for 1–48 h. The ΨW was measured continuously with stem psychrometers. Rewatered L. nobilis held at the target ΨW for 1 h showed no evidence for refilling unless ΨW was within a few tenths of a MPa of zero. In contrast, re‐watered L. nobilis held for 24 and 48 h at water potentials well below zero showed a significant reduction in PLC. The recovery was highly variable, being complete in some stem segments, and scarcely evident in others. Embolism repair was accompanied by a significant but moderate decrease in the osmotic potential (Ψ) of the bulk xylem sap (Ψ = −67 kPa in recovering plants versus −31 kPa in controls). In contrast, embolized and re‐watered A. negundo plants held for 24 h at target ΨW of −0·9 and −0·3 MPa showed no embolism reversal. The mechanism allowing L. nobilis plants to refill under negative pressure is unknown, but does not appear to operate in A. negundo, and is slower to act for drought‐induced embolism than when embolism was artificially induced by air injection as previously shown for L. nobilis.

Effects of some growth regulators on in vitro flowering of Streptocarpus nobilis

Leaf discs from vegetative Streptocarpus nobilis plants were cultured in vitro in media with cytokinin (BAP or K at 0.35 mg.1(-1)) and auxin (IAA, NAA or 2,4-D at 0.1 mg.1(-1)). Under short days (8-h photoperiod) in medium with IAA and BAP, floral buds developed in 100% of the cultures; under long days (16-h photoperiod) only shoots were formed. In medium with IAA and K, flowering was reduced. Flowers rarely formed in medium containing NAA and K, but roots developed profusely. NAA + BAP promoted leafy shoots which rarely flowered later. The effect of 2,4-D was to inhibit flowering completely and to induce callusing and formation of teratomous structures.