María Amparo Blázquez

Chemical Composition of the Essential Oils of Pistacia atlantica Desf.

Abstract The chemical composition of the three essential oils obtained by hydrodistillation of the resin, leaves and fruits of Pistacia atlantica Desf. (Anacardiaceae) was studied by GC and GC/MS. Monoterpene hydrocarbons constituted the main chemical group in the resin oil, with α-pinene (42.9%) and β-pinene (13.2%) as the major components. Oil of the fruits contained high amounts of oxygenated monoterpenes, with bornyl acetate (21.5%) as the major component, while oxygenated monoterpenes and sesquiterpenes were found to predominate in the oil of leaves among which terpinen-4-ol (21.7%) and elemol (20.0%) were the most abundant components.

New alkaloid antibiotics that target the DNA topoisomerase I of Streptococcus pneumoniae.

Streptococcus pneumoniae has two type II DNA-topoisomerases (DNA-gyrase and DNA topoisomerase IV) and a single type I enzyme (DNA-topoisomerase I, TopA), as demonstrated here. Although fluoroquinolones target type II enzymes, antibiotics efficiently targeting TopA have not yet been reported. Eighteen alkaloids (seven aporphine and 11 phenanthrenes) were semisynthesized from boldine and used to test inhibition both of TopA activity and of cell growth. Two phenanthrenes (seconeolitsine and N-methyl-seconeolitsine) effectively inhibited both TopA activity and cell growth at equivalent concentrations (∼17 μm). Evidence for in vivo TopA targeting by seconeolitsine was provided by the protection of growth inhibition in a S. pneumoniae culture in which the enzyme was overproduced. Additionally, hypernegative supercoiling was observed in an internal plasmid after drug treatment. Furthermore, a model of pneumococcal TopA was made based on the crystal structure of Escherichia coli TopA. Docking calculations indicated strong interactions of the alkaloids with the nucleotide-binding site in the closed protein conformation, which correlated with their inhibitory effect. Finally, although seconeolitsine and N-methyl-seconeolitsine inhibited TopA and bacterial growth, they did not affect human cell viability. Therefore, these new alkaloids can be envisaged as new therapeutic candidates for the treatment of S. pneumoniae infections resistant to other antibiotics.

Herbicidal Activity of Peumus boldus and Drimys winterii Essential Oils from Chile

The essential oil composition of Peumus boldus and Drimys winterii was analyzed by means of capillary GC-FID and GC-MS. More than 96% of the total oil components (43 and 54 compounds, respectively) were identified, with ascaridole (51.17 ± 9.51), p-cymene (16.31 ± 2.52) and 1,8-cineole (14.45 ± 2.99) as the main compounds in P. boldus and γ-eudesmol (21.65 ± 0.41), followed of elemol (12.03 ± 0.34) and terpinen-4-ol (11.56 ± 1.06) in D. winterii. The herbicidal activity was tested against Amaranthus hybridus and Portulaca oleracea. P. boldus essential oil was the most phytotoxic against both weeds, inhibiting seed germination and seedling growth at all concentrations assayed (0.125–1 µL/mL). D. winterii essential oil did not show any effect on A. hybridus germination and only affected P. oleracea germination at the highest concentration. The results suggest the possible use of the essential oil from P. boldus as a natural herbicide.

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.

Effect of boldine, secoboldine, and boldine methine on angiotensin II‐induced neurtrophil recruitment in vivo

Angiotensin‐II (Ang‐II) has inflammatory activity and is involved in different diseases associated with the cardiovascular system. This study has evaluated the effect of boldine (B), and two phenanthrene alkaloids semisynthesized by us, secoboldine (SB) and boldine methine (BM), on Ang‐II‐induced neutrophil recruitment. Intraperitoneal administration of 1 nM Ang‐II induced significant neutrophil accumulation, which was maximal at 4–8 h. BM inhibited neutrophil infiltration into the peritoneal cavity at 4 h and 8 h by 73% and 77%, respectively, SB at 8 h by 55%, and B had no effect on this response. Although BM inhibited the release of cytokine‐inducible neutrophil chemoattractant/keratinocyte‐derived chemokine, macrophage inflammatory protein‐2 (MIP‐2), and platelet‐activating factor (PAF) elicited by Ang‐II, SB only reduced the release of MIP‐2 after 4 h of its administration. Sixty‐minute superfusion of the rat mesentery with 1 nM Ang‐II induced a significant increase in the leukocyte‐endothelial cell interactions and P‐selectin up‐regulation, which were inhibited by 1 μM BM and SB. The generation of reactive oxygen species (ROS) in endothelial cells stimulated with Ang‐II was inhibited significantly by the three alkaloids tested. BM also diminished Ang‐II‐induced interleukin‐8 release from endothelial cells and blocked the PAF receptor on human neutrophils (concentration of the compound needed to produce 50% inhibition value: 28.2 μM). Therefore, BM is a potent inhibitor of Ang‐II‐induced neutrophil accumulation in vivo. This effect appears to be mediated through inhibition of CXC chemokine and PAF release, ROS scavenging activity, and blockade of the PAF receptor. Thus, it may have potential therapeutic interest for the control of neutrophil recruitment that occurs in inflammation associated with elevated levels of Ang‐II.

Effect of two phenanthrene alkaloids on angiotensin II‐induced leukocyte–endothelial cell interactions in vivo

The present study has evaluated the effect of two phenanthrene alkaloids, uvariopsine and stephenanthrine, on angiotensin II (Ang‐II)‐induced leukocyte–endothelial cell interactions in vivo and the mechanisms involved in their activity. Intravital microscopy within the rat mesenteric microcirculation was used. A 60 min superfusion with 1 nM Ang‐II induced a significant increase in the leukocyte–endothelial cell interactions that were completely inhibited by 1 μM uvariopsine cosuperfusion. A lower dose of 0.1 μM significantly reduced Ang‐II‐induced leukocyte adhesion by 75%. When Ang‐II was cosuperfused with 1 and 0.1 μM stephenanthrine, Ang‐II‐induced leukocyte responses were significantly diminished. A lower dose of 0.01 μM only affected Ang‐II‐induced leukocyte adhesion. Both alkaloids inhibited Ang‐II‐induced endothelial P‐selectin upregulation and the generation of reactive oxygen species (ROS) in endothelial cells stimulated with Ang‐II, in fMLP‐stimulated human neutrophils (PMNs) and in the hypoxanthine–xanthine oxidase system. However, cyclic AMP levels in PMNs stimulated with fMLP were not affected. Uvariopsine and stephenanthrine inhibited PAF‐induced elevations in intracellular calcium levels in PMNs (IC50 values: 15.1 and 6.1 μM respectively) and blocked the binding of [3H]PAF to these leukocytes. They also reduced PAF‐induced increases in intracellular levels of superoxide anion and hydrogen peroxide. In conclusion, stephenanthrine and uvariopsine are potent inhibitors of Ang‐II‐induced leukocyte accumulation in vivo. This effect appears to be mediated through ROS scavenging activity and blockade of PAF receptor. Thus, they have potential therapeutic interest for the control of leukocyte recruitment that occurs in cardiovascular disease states in which Ang‐II is involved.

Composition and Antimicrobial Activity of Essential Oil of Anthemis tenuisecta Ball

Abstract The Chemical composition of the essential oil of Anthemis tenuisecta Ball. (Anthemideae) was analyzed by gas Chromatography-mass spectrometry (GC-MS). Forty eight components accounting for 89.5 % of the oil were identified, being camphor (17.5 %), 6-methyl-5-hepten-2-one (17.1 %), borneol (11.5 %), sesquicineole (11%) and camphene (5.7 %) the main compounds. In the antibacterial diffusion assay, the oil showed activity against Gram-positive bacteria.

Chemical composition and antimicrobial activity of the essential oil of Curcuma leucorhiza Roxb

The essential oils obtained by hydrodistillation from the rhizomes and leaves of Curcuma leucorhiza Roxb. were analyzed by gas chromatography (GC) and GC/mass spectrometry (GC/MS) for the first time. A total of forty-nine compounds were identified in both oils. The main compounds in the rhizome and leaf oils were germacrone (9.6–19.7%), curdione (19.1–19.5%), camphor (7.2–8.1%), 1,8-cineole (4.0–7.4%), curzerene (3.0–5.7%), linalool (5.2–5.4%), neo-curdione (2.8–4.6%) and isoborneol (2.0–3.8%). Screening of the essential oils showed promising antibacterial activity (7–16 mm inhibition zone) against Streptococcus mutans, Pseudomonas putida, Bacillus subtilis, Klebsiella pneumoniae and antifungal activity (9–14 mm inhibition zone) against Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Candida albicans at 20 μg/disc of the oil by disc diffusion method as compared with standards.

Synthesis and reactive oxygen species scavenging activity of halogenated alkaloids from boldine

Six halogenated alkaloids have been semi-synthesized from natural boldine as starting material. Their antioxidant activity toward reactive oxygen species (ROS) generation by neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine and in the hypoxanthine–xanthine oxidase system was evaluated. Most of the alkaloids synthesized inhibited ROS generation in both systems in a concentration-dependent manner. The alkaloids with phenolic substituents displayed more powerful anti-oxidative activity than those containing methoxylated groups. None of the alkaloids assayed had any effect on xanthine oxidase activity. Therefore, halogenated phenanthrene alkaloids can become in promising candidates for the development of novel and potent anti-inflammatory drugs.

Artemisia arborescens L.: essential oil composition and effects of plant growth stage in some genotypes from Sicily

Essential oils from aerial parts of several Artemisia arborescens L. populations, collected in five different localities of Sicily, were analyzed by gas chromatograph–flame ionization detector (GC–FID) and GC–mass spectrometry (GC–MS) in order to study the chemical composition and its variability due to phenological stage. Forty-three compounds, accounting for more than 92% of the oil, were identified. Monoterpene fraction with the exception of Petru population was higher than the sesquiterpene fraction. β-Thujone (20.5–55.9%), chamazulene (15.2–49.4%), camphor (1.3–10.7%) and germacrene D (2.3–3.4%) were the main compounds. Chemical composition was influenced by phenological stage, with an increase in the monoterpene fraction at flowering stage; both in flowering and vegetative stages, the main compounds were always the oxygenated monoterpene β-thujone and the sesquiterpene hydrocarbon chamazulene.