76 research outputs found
Myriolecis massei, a new species of Lecanoraceae from the coasts of the Armorican Massif in Western Europe
Phytochemical investigation of a lichen from Brittany, Stereocaulon evolutum Graewe
International audienc
EnquĂȘte sur la survenue dâintoxications aprĂšs lâutilisation dâhuiles essentielles, comparaison avec les donnĂ©es du CAP dâAngers (2017-2018)
National audienceObjectifsâ: Les mĂ©decines non conventionnelles ne sont pas dĂ©nuĂ©es de toxicitĂ© et il est pertinent dâĂ©tablir un Ă©tat des lieux des connaissances du grand public vis-Ă -vis des huiles essentielles. Il sâagit dâidentifier le profil des victimes dâune intoxication, les voies dâadministration et les symptĂŽmes ainsi que les huiles essentielles incriminĂ©es.MĂ©thodesâ: Deux enquĂȘtes, Ă destination du grand public et des professionnels de santĂ©, ont Ă©tĂ© diffusĂ©es (janvier-mars 2019). En complĂ©ment, les donnĂ©es du centre antipoison dâAngers sur la pĂ©riode 2017-2018 ont Ă©tĂ© analysĂ©es et comparĂ©es avec les donnĂ©es de notre enquĂȘte.RĂ©sultatsâ: Nos enquĂȘtes rassemblent 623 et 59 rĂ©ponses. Les donnĂ©es du centre antipoison dâAngers recensent 741 intoxications. Les prĂ©cautions dâemploi et les contre-indications des huiles essentielles sont peu connues puisque 5% des rĂ©pondants les identifient correctement. Nos donnĂ©es mettent en Ă©vidence quâune utilisation en mĂ©lange augmente le risque dâintoxication (pâ<â0,02). Les huiles essentielles les plus citĂ©es en cas dâintoxication sont lâEucalyptus, le Tea tree et la Lavande. Les symptĂŽmes occasionnĂ©s concernent majoritairement une application cutanĂ©e (75%) et restent de courte durĂ©e et sans gravitĂ©. Lors dâune dĂ©claration au centre antipoison dâAngers, ces mĂȘmes huiles essentielles sont impliquĂ©es, la voie orale est majoritaire utilisĂ©e (70%) et les symptĂŽmes rĂ©pertoriĂ©s pour 74% des intoxications concernent des douleurs oropharyngĂ©es, oculaires, abdominales et cutanĂ©es.Conclusionâ: La dĂ©livrance des huiles essentielles nâest pas anodine et les donnĂ©es obtenues tant Ă travers lâenquĂȘte que le traitement des donnĂ©es du centre antipoison dâAngers montrent quâelles doivent ĂȘtre utilisĂ©es avec prudence
Myriolecis massei, a new species of Lecanoraceae from the coasts of the Armorican Massif in Western Europe
International audienceA new species of Lecanora s.l. (Lecanoraceae) has been found in several localities on the coasts of the Armorican Massif (Brittany, Normandy, Channel Islands), only on siliceous rocks in the supralittoral zone. It is particularly distinguished by its well-developed thallus reacting C+ orange in the cortex and containing chlorinated xanthones identified by HPLC-DAD-MS. Placed in the new genus Myriolecis, it is described in this study as Myriolecis massei sp. nov. and is compared to similar maritime species containing chloroxanthones. A key is given to European maritime species of Myriolecis reacting C+. Copyright © 2018 by The American Bryological Society, Inc
Stability of oral liquid preparations of methylergometrine
International audienceThe stability of an oral ready to-use form of methylergometrine (0.05 mg/mL), which provides a convenient volume for administration (5 mL), was evaluated over a forty-seven-day period at different temperatures (5 degrees C and room temperature) without light in order to assign a shelf life. Methylergometrine was assayed by a stability-indicating HPLC method with diode array detection. The drug undergoes degradation under basic conditions and dry heat (50 degrees C). All the peaks of the degraded product were resolved from the standard drug with significantly different retention times. Statistical analysis proves that the method is reproducible and accurate for estimation of the intact drug. The pH of samples was monitored periodically for changes. Samples were also visually inspected for any colour change, precipitation or crystallization. At least, 96% of the initial methylergometrine concentration remained throughout the 47-day study period. Over the test period, no significant change was observed in the pH or colour of any of the samples. No degradation products were revealed. This study allowed an oral ready to use solution of methylergometrine (0.05 mg/ml) to be prepared, with a shelf life of more than one month (47 days) when stored at room temperature without light
Lichenic extracts and metabolites as UV filters.
International audienceThree lichen extracts and ten lichenic compounds have been screened for their photoprotective activities. The determination of their Sun Protection Factor (SPF) and Protection Factor-UVA (PF-UVA) values was done in vitro. Among them, a Lasallia pustulata extract and gyrophoric acid exhibited SPF values over 5, which is better than Homosalate (SPFâ4). Their photoprotective properties are only slightly modified after a 2-hours period of irradiation. Salazinic acid and L. pustulata presented characteristics of a UVA booster like the butyl-methoxydibenzoylmethane (Avobenzone) (PF-UVAâ2 vs. 2.8 for Avobenzone). Salazinic acid was a better anion superoxide scavenger than ascorbic acid and none of them exhibited a photosensitizing cytotoxicity by exposing them on HaCaT cells to UVA radiations (photo-irritancy factor PIF<5)
Comparative studies on two Sumatran lichens: Sterocaulon halei and S. montagneanum
International audienc
A novel aryl-hydrazide from the marine lichen Lichina pygmaea: isolation, synthesis of derivatives, and cytotoxicity assays.
International audienceA new aryl-hydrazide l-glutamic acid derivative, pygmeine (3), was isolated from a methanolic extract of Lichina pygmaea, a marine lichen. Synthetic derivatives obtained via a two-step coupling of l-glutamic acid with phenylhydrazine moieties were useful to elucidate the structure of 3 and to carry out biological assays. Thus, the cytotoxicity of the ortho-, meta-, and para-hydroxyl isomers along with their respective benzyl intermediates, and a natural methoxylated analog, were evaluated on murine and human melanoma cells (B16, A375). The para-hydroxyl isomer 6 was found to be the most active (IC(50)=1.6 microM) on B16 cells
Oxidative stress regulation in lichens and its relevance for survival in coastal habitats
International audienceLichens are symbiotic systems able to survive in harsh conditions like those on coastal rocks with rapid changes in the concentration of salt, immersion, desiccation-rehydratation cycle, wind, waves and herbivorie. These stresses are at the origin of reactive oxygen species (ROS) production in lichens. Physical barriers, enzymatic systems and cellular contents of glutathione, ascorbic acid and tocopherols are involved in lichen defence systems against ROS. But which role have specific lichen compounds, e.g.: the depsides, depsidones, dibenzofuranes, diphenylethers as antioxidants? In order to answer this question, antioxidant studies were recorded and analysed for studies for lichens that occur on coastal rocks. Based on the methods used in the experiments (hydrogen atom transfer (HAT), electron transfer (ET), enzymatic assays, specific ROS scavenging, in vivo assays), lichen compounds seemed to be poor hydrogen acceptors and electron donors but appeared as potent ROS specific scavengers, they might act as antioxidants as proved by the positive results of many lichen extracts in antioxidant assays
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