ICS-29: The 29th International Carbohydrate Symposium

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Synthesis of new pseudo‐C‐nucleosides containing pyrazole rings in their structure

Synthetic approaches to new 4-(furanos-4-C-yl)-1H-pyrazole and 3-(furanos-4-C-yl)-1H-pyrazole derivatives are described, including its pyrazole-5-carboxylate derivative, which is a pyrazofurin analogue. Preparation of related 5-acetoxy-1-acetyl-1H-pyrazole, 5-acetoxy-1H-pyrazole-1-carboxylate, and 4,5-dihydro-1-phenyl-1H-pyrazol-5-one derivatives is also reported. The formation of the pyrazole rings was accomplished either by reaction of enones and of 1,3-diketones with N-nucleophiles or by ring closure of a diazoketone.info:eu-repo/semantics/publishedVersio

Design and Synthesis of CNS-targeted Flavones and Analogues with Neuroprotective Potential Against H2O2- and Aβ1-42-Induced Toxicity in SH-SY5Y Human Neuroblastoma Cells

With the lack of available drugs able to prevent the progression of Alzheimer’s disease (AD), the discovery of new neuroprotective treatments able to rescue neurons from cell injury is presently a matter of extreme importance and urgency. Here, we were inspired by the widely reported potential of natural flavonoids to build a library of novel flavones, chromen-4-ones and their C-glucosyl derivatives, and to explore their ability as neuroprotective agents with suitable pharmacokinetic profiles. All compounds were firstly evaluated in a parallel artificial membrane permeability assay (PAMPA) to assess their effective permeability across biological membranes, namely the blood-brain barrier (BBB). With this test, we aimed not only at assessing if our candidates would be well-distributed, but also at rationalizing the influence of the sugar moiety on the physicochemical properties. To complement our analysis, logD7.4 was determined. From all screened compounds, the p-morpholinyl flavones stood out for their ability to fully rescue SH-SY5Y human neuroblastoma cells against both H2O2- and Aβ1-42-induced cell death. Cholinesterase inhibition was also evaluated, and modest inhibitory activities were found. This work highlights the potential of C-glucosylflavones as neuroprotective agents, and presents the p-morpholinyl C-glucosylflavone 37, which did not show any cytotoxicity towards HepG2 and Caco-2 cells at 100 μM, as a new lead structure for further development against AD.Fundação para a Ciência e a Tecnologia-UID/Multi/0612/2019Unión Europea-D3i4AD), FP7-PEOPLE-2013-IAPP, GA 61234

A new dihydroxysterol from the marine phytoplankton Diacronema sp.

Diacronema sp. was cultured and its sterols were separated by column chromatography on silica gel. The new sterol 24-ethyl-4α-methyl-cholestane-3,20-diol (1) was characterised by NMR and MS spectrometry, as well as (22E)-24-ethyl-4α-methyl-5α-cholest-22-en-3β-ol (2) and β-sitosterol, the major components of the sterol fractions. Neither the biosynthetic origin of the new dihydroxysterol nor its role in the biochemistry of Diacronema is known.info:eu-repo/semantics/publishedVersio

A novel pentacyclic triterpene from Leontodon filii

A novel oleanene triterpenetetrol was isolated from the chloroform extract of the aerial parts of Leontodon filii. Its structure was shown to be 2β,3β,15α,21β-olean-12-ene-2,3,15,21-tetrol by chemical and spectroscopic methods. The fungicidal efficacy of the chloroform and methanol extracts of the plant was also evaluated, a protective effect being found against Plasmopara viticola, Botrytis cinerea, particularly powerful against Pyricularia oryzae.info:eu-repo/semantics/publishedVersio

Synthesis of sugars embodying conjugated carbonyl systems and related triazole derivatives from carboxymethyl glycoside lactones. Evaluation of their antimicrobial activity and toxicity.

International audienceThe synthesis of a series of pyranoid derivatives comprising a conjugated carbonyl function and related triazole derivatives, structurally suitable for bioactivity evaluation, was achieved in few steps starting from readily available carboxymethyl glycoside lactones (CMGL). 3-Enopyranosid-2-uloses were generated by oxidation/elimination of tri-O-acylated 2-hydroxy pyranosides. Subsequent Wittig olefination provided stereoselectively 2-C-branched-chain conjugated dienepyranosides with (E)-configuration around the exocyclic double bond. A heterogeneous CuI/Amberlyst-catalyzed 'click' chemistry protocol was used to convert glycosides bearing a propargyl moiety into the corresponding 1,2,3-triazoles. These new molecules were screened for their in vitro antibacterial and antifungal activities and those containing conjugated carbonyl systems demonstrated the best efficacy. (N-Dodecylcarbamoyl)methyl enone glycerosides were the most active ones among the enones tested. The α-anomer displayed very strong activities against Bacillus cereus and Bacillus subtilis and strong activity toward Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The corresponding β-anomer presented a very strong inhibitory effect against two fungal species (Aspergillus niger and P. aurantiogriseum). (N-Dodecyl-/N-propargyl/or N-benzylcarbamoyl)methyl dienepyranosides exhibited selectively a strong activity toward E. faecalis. Further acute toxicity evaluation indicated low toxic effect of the (N-dodecylcarbamoyl)methyl enone glyceroside α-anomer and of the carbamoylmethyl dienepyranosides N-protected with propargyl or benzyl groups

Unlocking the in vitroanti- inflammatory and antidiabetic potential of Polygonum maritimum

Context: Several Polygonum species (Polygonaceae) are used in traditional medicine in Asia, Europe and Africa to treat inflammation and diabetes. Objective: Evaluate the in vitro antioxidant, anti-inflammatory and antidiabetic potential of methanol and dichloromethane extracts of leaves and roots of the halophyte Polygonum maritimum L. Material and methods: Antioxidant activity was determined (up to 1mg/mL) as radical-scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), copper (CCA) and iron (ICA) chelating activities and iron reducing power (FRAP). NO production was measured in lipopolysaccharide (LPS)-stimulated macrophages for 24 h at concentrations up to 100 mu g/mL and antidiabetic potential was assessed by alpha-amylase and alpha-glucosidase inhibition (up to 10 g/mL) assays. The phytochemical composition of the extracts was determined by gas chromatography-mass spectrometry (GC-MS). Results: The methanol leaf extract had the highest activity against DPPH center dot (IC50 = 26 mu g/mL) and ABTS1(+)center dot (IC50 = 140 mu g FRAP (IC50 = 48 mu g/mL) and CCA (IC50 = 770 mu g/mL). Only the dichloromethane leaf extract (LDCM) showed anti-inflammatory activity (IC50 = 48 mu g/mL). The methanol root (IC50 = 19 mu g/mL) and leaf (IC50 = 29 mu g/mL) extracts strongly inhibited baker's yeast alpha-glucosidase, but LDCM had higher rat's alpha-glucosidase inhibition (IC50 = 2527 mu g/mL) than acarbose (IC50 = 4638 mu g/mL). GC-MS analysis identified beta-sitosterol, stigmasterol, 1-octacosanol and linolenic acid as possible molecules responsible for the observed bioactivities. Conclusions: Our findings suggest P. maritimum as a source of high-value health promoting commodities for alleviating symptoms associated with oxidative and inflammatory diseases, including diabetes.XtremeBio project - Foundation for Science and Technology (FCT) [PTDC/MAR-EST/4346/2012]; Portuguese National Budget; FCT [CCMAR/Multi/04326/ 2013, IF/00049/2012, SFRH/BPD/86071/2012, UID/Multi/00612/2013

Proximate biochemical composition and mineral content of edible species from the genus Cystoseira in Portugal

Macroalgae are valuable resources for human consumption in many countries. This work reports for the first time a comparative evaluation of the nutritional properties of five edible macroalgae from the genus Cystoseira, namely C. humilis, C. tamariscifolia, C. nodicaulis, C. compressa and C. baccata. For this purpose, their proximate composition was determined in terms of moisture, ash, and total contents of protein, lipids, carbohydrates and mineral profile. Cystoseira tamariscifolia and C. baccata were the species that in general had the higher ash, protein and lipid contents, while the highest levels of moisture and total carbohydrates were detected in C. nodicaulis and C. compressa. Cystoseira species had also high amounts of minerals, especially of potassium, calcium and iron, and a favorable Na/K ratio. The present study shows that Cystoseira has a balanced nutritional composition, suitable for human consumption, and that its intake can contribute to a healthy and well-balanced diet

Liquid chromatography–diode array detection–electrospray ionisation mass spectrometry/nuclear magnetic resonance analyses of the anti-hyperglycemic flavonoid extract of Genista tenera Structure elucidation of a flavonoid-C-glycoside

The anti-hyperglycemic flavonoid extract obtained from Genista tenera was first studied by liquid chromatography (LC)–diode array detection (DAD) which showed the presence of two major compounds. One of them was identified as genistein-7-O-glucoside. Luteolin-7-O-glucoside was detected as a minor constituent, while luteolin-7,3′-di-O-glucoside and rutin were found in trace amounts. LC–DAD–ESI–MS and NMR were used to confirm the structure of these compounds and allowed the elucidation of the structure of the unknown major compound, which is the flavonoid 5,7,4′-trihydroxyisoflavone-8-C-glucoside.info:eu-repo/semantics/publishedVersio

Sugar bislactones by one-step oxidative dimerisation with pyridinium chlorochromate versus regioselective oxidation of vicinal diols

Synthesis of 10-membered bislactones by PCC oxidation of methyl 2,6-di-O-pivaloyl-α-D-glucopyranoside and methyl 4,6-O-benzylidene-α-D-glucopyranoside is described, with emphasis on their structure elucidation using the information gained by combination of NMR spectroscopic techniques with X-ray diffraction data. In alternative, the use of PCC and PCC adsorbed on silica gel or alumina for the regioselective oxidation of vicinal diols in sugars is also reported. Both bislactones showed antifungal activity against Candida albicans, and were slightly active against the bacteria Bacillus subtilis. The bislactone presenting pivaloyl protecting groups also promoted some growth inhibition of Staphylococcus aureus.info:eu-repo/semantics/publishedVersio