SciCombinator

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Concept: Laurus

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The accurate identification of bay leaf in natural products commerce may often be confusing as the name is applied to several different species of aromatic plants. The true “bay leaf”, also known as “bay laurel” or “sweet bay”, is sourced from the tree Laurus nobilis, a native of the Mediterranean region. Nevertheless, the leaves of several other species including Cinnamomum tamala, Litsea glaucescens, Pimenta racemosa, Syzygium polyanthum, and Umbellularia californica are commonly substituted or mistaken for true bay leaves due to their similarity in the leaf morphology, aroma, and flavor. Substitute species are, however, often sold as “bay leaves”. As such, the name “bay leaf” in literature and herbal commerce may refer to any of these botanicals. The odor and flavor of these leaves are, however, not the same as the true bay leaf, and for that reason they should not be used in cooking as a substitute for L. nobilis. Some of the bay leaf substitutes can also cause potential health problems. Therefore, the correct identification of the true bay leaf is important. The present work provides a detailed comparative study of the leaf morphological and anatomical features of L. nobilis and its common surrogates to allow for correct identification.

Concepts: Plant morphology, Essential oil, Herbs, Lauraceae, Laurus, Malabathrum, Bay Laurel, Laurales genera

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The present study demonstrated the antifungal potential of the chemically characterized essential oil (EO) of Laurus nobilis L. (bay laurel) against Candida spp. biofilm adhesion and formation, and further established its mode of action on C. albicans.

Concepts: Candida albicans, Candidiasis, Essential oil, Lauraceae, Laurus, Apollo, Bay Laurel, Wu Gang

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Drought-induced xylem embolism is a serious threat to plant survival under future climate scenarios. Hence, accurate quantification of species-specific vulnerability to xylem embolism is a key to predict the impact of climate change on vegetation. Low-cost hydraulic measurements of embolism rate have been suggested to be prone to artefacts, thus requiring validation by direct visualization of the functional status of xylem conduits using nondestructive imaging techniques, such as X-ray microtomography (microCT). We measured the percentage loss of conductance (PLC) of excised stems of Laurus nobilis (laurel) dehydrated to different xylem pressures, and compared results with direct observation of gas-filled vs water-filled conduits at a synchrotron-based microCT facility using a phase contrast imaging modality. Theoretical PLC calculated on the basis of microCT observations in stems of laurel dehydrated to different xylem pressures overall were in agreement with hydraulic measurements, revealing that this species suffers a 50% loss of xylem hydraulic conductance at xylem pressures averaging -3.5 MPa. Our data support the validity of estimates of xylem vulnerability to embolism based on classical hydraulic techniques. We discuss possible causes of discrepancies between data gathered in this study and those of recent independent reports on laurel hydraulics.

Concepts: Scientific method, Measurement, Observation, Climate change, Hypothesis, Lauraceae, Laurus, Bay Laurel

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Costunolide (CE) and dehydrocostuslactone (DE) are derived from many species of medicinal plants, such as Saussurea lappa Decne and Laurus nobilis L. They have been reported for their wide spectrum of biological effects, including anti-inflammatory, anticancer, antiviral, antimicrobial, antifungal, antioxidant, antidiabetic, antiulcer, and anthelmintic activities. In recent years, they have caused extensive interest in researchers due to their potential anti-cancer activities for various types of cancer, and their anti-cancer mechanisms, including causing cell cycle arrest, inducing apoptosis and differentiation, promoting the aggregation of microtubule protein, inhibiting the activity of telomerase, inhibiting metastasis and invasion, reversing multidrug resistance, restraining angiogenesis has been studied. This review will summarize anti-cancer activities and associated molecular mechanisms of these two compounds for the purpose of promoting their research and application.

Concepts: Immune system, DNA, Cancer, Chemotherapy, Cell cycle, DNA replication, Mitosis, Laurus

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Bay laurel (Laurus nobilis L.) is an agriculturally and economically important dioecious tree in the basal dicot family Lauraceae used in food, drugs and the cosmetics industry. Bay leaves, with their abundant monoterpenes and sesquiterpenes, are used to impart flavor and aroma to food, and have also drawn attention in recent years due to their potential pharmaceutical applications. To identify terpene synthases involved in the production of these volatile terpenes, we performed RNA-seq to profile the transcriptome of Laurus nobilis leaves. Bioinformatic analysis led to the identification of eight terpene synthase cDNAs. We characterized the enzymes encoded by three of these cDNAs - a monoterpene synthase that belongs to the TPS-b clade catalyzes the formation of mostly 1,8-cineole, a sesquiterpene synthase belonging to the TPS-a clade that catalyzes the formation of mainly cadinenes, and a diterpene synthase of the TPS-e/f clade catalyzing the formation of geranyllinalool. Comparison of the sequences of these three TPSs indicated that the TPS-a and TPS-b clades of the TPS gene family evolved early in the evolution of the angiosperm lineage, and that geranyllinalool synthase activity is the likely ancestral function in angiosperms of genes belonging to an ancient TPS-e/f subclade that diverged from the kaurene synthase gene lineages before the split of angiosperms and gymnosperms.

Concepts: DNA, Gene, Gene expression, Evolution, Terpene, Lauraceae, Laurus, Bay Laurel

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Bay laurel (Laurus nobilis L.) is an agriculturally important tree used in food, drugs, and the cosmetics industry. Many of the health beneficial properties of bay laurel are due to volatile terpene metabolites that they contain, including various norisoprenoids. Despite their importance, little is known about the norisoprenoid biosynthesis in Laurus nobilis fruits. We found that the volatile norisoprenoids 6-methyl-5-hepten-2-one, pseudoionone, and β-ionone accumulated in Laurus nobilis fruits in a pattern reflecting their carotenoid content. A full-length cDNA encoding a potential carotenoid cleavage dioxygenase (LnCCD1) was isolated. The LnCCD1 gene was overexpressed in Escherichia coli, and recombinant protein was assayed for its cleavage activity with an array of carotenoid substrates. The LnCCD1 protein was able to cleave a variety of carotenoids at the 9,10 (9',10') and 5,6 (5',6') positions to produce 6-methyl-5-hepten-2-one, pseudoionone, β-ionone, and α-ionone. Our results suggest a role for LnCCD1 in Laurus nobilis fruit flavor biosynthesis.

Concepts: DNA, Metabolism, Recombinant DNA, Escherichia coli, Lycopene, Lauraceae, Laurus, Bay Laurel

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Laurus nobilis L. is an aromatic herb with relevant medicinal properties due to its important chemical composition and its potential therapeutic effects. In this study, we investigate the chemical composition, the antibacterial and the antibiofilms activities of Tunisian L. nobilis L. essential oils against clinical Staphylococcus aureus strains.

Concepts: Staphylococcus aureus, Ethanol, Tea tree oil, Essential oil, Oil, Oils, Laurus

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Medicinal and aromatic plants are used since ancient times in folk medicine and traditional food, but also in novel pharmaceutical preparations. The controversy lies in the use of cultivated and/or wild plants presenting both advantages and disadvantages in biological, ecological but also economic terms. Herein, cultivated and wild samples of Laurus nobilis L. were chemically characterized regarding nutritional value, free sugars, organic acids, fatty acids and tocopherols. Furthermore, the antioxidant activity (scavenging activity, reducing power and lipid peroxidation inhibition) and individual phenolic profile of L. nobilis extracts and infusions were evaluated. Data showed that the wild sample gave higher nutritional contribution related to a higher content of proteins, free sugars, organic acids, PUFA and tocopherols. It also gave better PUFA/SFA and n-6/n-3 ratios. Regarding antioxidant activity and phenolic compounds, it was the cultivated sample (mostly the infusion) that showed the highest values. The present study supports the arguments defending the use of wild and cultivated medicinal and aromatic plants as both present very interesting features, whether nutritional or antioxidant, that can be an assessed by their consumption. In vitro culture could be applied to L. nobilis as a production methodology that allows combination of the benefits of wild and cultivated samples.

Concepts: Protein, Metabolism, Nutrition, Fatty acid, Antioxidant, Lipid, Vitamin E, Laurus

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Sap water is distributed and utilized through xylem conduits, which are vascular networks of inert pipes important for plant survival. Interestingly, plants can actively regulate water transport using ion-mediated responses and adapt to environmental changes. However, ionic effects on active water transport in vascular plants remain unclear. In this report, the interactive ionic effects on sap transport were systematically investigated for the first time by visualizing the uptake process of ionic solutions of different ion compositions (K+/Ca2+) using synchrotron X-ray and neutron imaging techniques. Ionic solutions with lower K+/Ca2+ ratios induced an increased sap flow rate in stems of Olea europaea L. and Laurus nobilis L. The different ascent rates of ionic solutions depending on K+/Ca2+ ratios at a fixed total concentration increases our understanding of ion-responsiveness in plants from a physicochemical standpoint. Based on these results, effective structural changes in the pit membrane were observed using varying ionic ratios of K+/Ca2+. The formation of electrostatically induced hydrodynamic layers and the ion-responsiveness of hydrogel structures based on Hofmeister series increase our understanding of the mechanism of ion-mediated sap flow control in plants.

Concepts: Plant, Water, Electrochemistry, Physical chemistry, Vascular plant, Olive, Laurus, Bay Laurel

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The inhibitory reagents to inhibit the activation of microglial cells may be potentially useful for the treatment of neurodegenerative diseases. The leaves of the plant Laurus nobilis belonging to the family Lauraceae, namely bay leaves, have been used as a popular spice and their extract showed moderate inhibition on the microglial activation. A further phytochemical investigation of the leaves led to the isolation of two new (1, 2) and eight known (310) sesquiterpenes. Their structures were elucidated on the basis of extensive 1D and 2D NMR (HMQC, HMBC, 1H-1H COSY, and NOESY) spectroscopic data analyses and Chem3D modeling. The following biological studies disclosed that these isolated compounds showed inhibitory activities on LPS-induced microglial activation. The results of our phytochemical investigation, including two new sesquiterpenes (1 and 2) and the first report of two compounds (3 and 4) from this species, further revealed the chemical composition of bay leaves as a popular spice and the biological studies implied that bay leaves, containing bioactive substances with the inhibition of microglial activation, were potentially beneficial to human health.

Concepts: Spectroscopy, Nuclear magnetic resonance, Inhibitor, Two dimensional correlation analysis, Xanthine oxidase inhibitor, Lauraceae, Laurus, Bay Laurel