A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Antioxidant Properties of Oak Bracket Mushroom, Pseudoinonotus dryadeus (Higher Basidiomycetes): A Mycochemical Study

A complex mixture of free fatty acids (1), cerevisterol (2), a sphingosine (3), and a complex mixture of diacylglycerophospholipids (4) were isolated from the fruiting body of the basidiomycete mushroom Pseudoinonotus dryadeus and subjected to spectroscopic analyses. The antioxidant activities of the whole extract of the fungus, of the isolated fractions, and of compounds 1\u20134 were evaluated in two in vitro model systems: 2,2-diphenyl-1-picryl- hydrazyl (DPPH) and superoxide anion. In each systems, the extract of fungus and compound 2 showed the same free radical scavenging activity (with SC50 data of 18.27 \u3bcg/mL and 5.75 \u3bcg/mL, respectively) compared with the positive control quercetin (DPPH assay). Compounds 1\u20134 were isolated from P. dryadeus for the first time

PEG\u2013Ursolic Acid Conjugate: Synthesis and In Vitro Release Studies

A highly water-soluble macromolecular compound of ursolic acid with mono-methoxypoly(ethylene glycol) (mPEG) was prepared. The physicochemical properties and stabilities under different conditions were investigated. By PEG conjugation, greatly increased water solubility was obtained, and the results showed that this conjugate was a potential prodrug for the oral delivery of ursolic acid

SYNTHESIS OF ALFA-ALKYLIDEN-GAMMA-LACTONES AS FAS INHIBITORS

a-Methylenelactones have received much attention due to the biological activity exhibited by natural products containing this structural moiety [1]. Cytotoxic, anti-inflammatory, phytotoxic, allergenic and antimicrobial properties are shown not only by highly functionalized, complex sesquiterpene lactones but also simple representatives were studied for their biological effects. Besides, compared to normal human tissues, many common human cancers, express high levels of fatty acid synthase (FAS), the primary enzyme responsible for the synthesis of fatty acids. This differential expression of FAS between normal tissues and cancer has led to the notion that FAS is a target for anticancer drug development [2]. A new series of a-methylene-g.butyrolactones has been synthesized with an alkylidene moiety in 3 position and a substution in 5 position. All the compounds were tested against PANC-1, HCT-116, Lovo, MCF-7 and MDA-231-MB tumor cell lines by MTT assay to different concentrations of the above compounds (4.1x10-7-3.0x10-4 ) after a 48 h exposition. The compound with R=H and R'= 3',5'- dimethoxyphenyl exhibited a pharmacological interesting cell toxicity profile in all cell lines with EC50 values similar to the reference compound cerulenine. References 1) F. Cateni et al. , European Journal of Medicinal Chemistry 41, (2006), 192-200. 2) F.P. Kuhajda et al. , Proc. Natl. Acad. Sci. USA 7, (2000), 3450-4

Lipid Metabolites from the Mushroom Meripilus giganteus

The phytochemical investigation of the methanolic extract of the white rot fungus Meripilus giganteus resulted in the isolation and identification of complex mixtures of free fatty acids (1), monoacylglycerols (2), cerebrosides (3), ergosterol (4) and ergosterol peroxide (5). The structures of the isolated lipid metabolites (1-5) were determined by chemical and spectroscopic methods. The antioxidant activity of the whole MeOH extract of the fungus was evaluated through in vitro model systems, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide anion. In all two systems, the results indicated that the extract of the fungus showed the same free-radical-scavenging activity with SC50 data of 47.70 \u3bcg/mL, compared with the positive control quercetin (DPPH assay). None of the isolated compounds (1-5) showed a significant activity. Compounds 2-4 were isolated from Meripilus giganteus for the first time