Some spectroscopic, kinetic and equilibria studies of Cyano- and nitro- substituted anisoles and phenols and their reactions with nucleophiles

The reactions of ring-activated alkyl aryl ethers with nucleophiles have been examined. The main pathways involve attack by the nucleophiles at the alkyl carbon to give substituted phenoxide ions, or at ring carbon atoms to give σ-adducts. The dealkylation reactions have been observed by both (^1)H nuclear magnetic resonance spectroscopy and spectrophotometrically using dimethyl sulphoxide as solvent. The reactivity order for nucleophiles in this solvent is SCN- Ca(^2+) > K(^+) > Na(^+) > Li(^+). This explains a longstanding discrepancy in the literature between the values of equilibrium constants for attack of lithium methoxide and of sodium methoxide. In concentrated solutions of sodium or potassium methoxide in methanol nitro-activated anisoles form adducts with 2:1 and 3:1 stoichiometry. Here methoxide addition occurs at two or three ring positions respectively. Such equilibria have been examined spectrophotometrically for 2,4,6-trinitroanisole, the isomeric cyanodinitroanisoles and the spiro-adduct formed by cyclisation of picryl glycol ether. For these equilibria the "basicity" of sodium methoxide solutions jn methanol is appreciably greater than that of corresponding potassium methoxide solutions. This is in contrast with other measures of basicity and is attributed to the association of the multi-charged adducts with cations which is stronger with sodium ions than with potassium ions. The infrared spectra of the parent and nitro-cyanoanisoles and their Meisenheimer complexes have been examined in the N0(_2) group, benzene ring and CN group regions. In order to attempt to understand their chemical and spectral behaviour the corresponding phenols and their Na(^+) and K(^+) salts have also been studied both in solution in dimethyl sulphoxide and in the solid state. Band shifts, widths and intensities have been interpreted in terms of the nature and extent of intra-molecular electronic rearrangements caused by the intermolecular interactions (hydrogen-bonding and cation coordination). Interesting, although not fully understood, differences in behaviour between the 2 and 4-CN substituted dinitrophenols and anisoles have been noted

Madeira moneywort (Sibthorpia peregrina L.) as a new source of verbascoside and its derivatives with potential phyto-pharmaceutical applications

The qualitative and quantitative characterization of Madeira moneywort (Sibthorpia peregrina L.) compounds was investigated for the first time. The antioxidant activity and the effect of the methanolic extract on digestive enzymes activity linked to type-2 diabetes and obesity were also determined by in vitro assays. A total of 56 components were characterized in S. peregrina. Phenylethanoids glycosides (PhEGs) represented the main classes of compounds (95.23 mg g-1 of dry extract), almost all verbascoside and its derivatives (up to 98.85% of the total individual phenolic content). The analysed sample was active against ABTS, DPPH, nitric oxide and superoxide radicals, suggesting a potential beneficial effect against oxidative stress. In addition, the methanolic extract was able to inhibit the catalytic activity of α-, β-glucosidases, α-amylase and pancreatic lipase. Overall, S. peregrina showed good perspectives to be explored as a rich source of verbascoside and its derivatives for nutraceutical/pharmaceutical products.This work was supported by Fundação para a Ciência e a Tecnologia (FCT, Portugal) [grant number SFRH/ BD/84672/2012] with funds from the Portuguese Government (Project PEst-OE/QUI/UI0674/2013) and the Portuguese National Mass Spectrometry Network (Contract RNEMREDE/1508/REM/2005). Funding through the project M1420-01-0145-FEDER-000005 – Centro de Química da Madeira – CQM+(Madeira 14-20).info:eu-repo/semantics/publishedVersio

Characterisation of phenolic acid derivatives and flavonoids from different morphological parts of Helichrysum obconicum by a RP-HPLC–DAD-(−)–ESI-MSn method

The phenolic composition from different morphological parts of Helichrysum obconicum was investigated for the first time and 50 different phenolic compounds were detected. Phenolic acid conjugates, mainly mono- and di-caffeoylquinic acid derivatives, were the major components; some flavonoid derivatives were also detected in small amounts. Their separation and identification was performed by a high-performance liquid chromatography/electron spray ionisation tandem ion trap mass spectrometry method, with special emphasis on MSn fragmentation. The presence of di- and tricaffeoylshikimic acid isomers in Helichrysum species extracts was reported for the first time, the spectra of these compounds were mainly characterised by the presence of a [caffeoylshikimic acid-H]- ion at m/z 335. A lamiridosins-di-O-hexoside, an unusual component in Asteraceae species, was also detected.info:eu-repo/semantics/publishedVersio

Evaluation of Asteraceae herbal extracts in the management of diabetes and obesity. Contribution of caffeoylquinic acids on the inhibition of digestive enzymes activity and formation of advanced glycation end-products (in vitro)

The study was performed to assess, for the first time, the in vitro anti-diabetic potential of ten Asteraceae plant extracts to inhibit the activity of digestive enzymes (α-amylase, α-, β-glucosidases and lipase) responsible for hydrolysis/digestion of sugar and lipids. Prevention of advanced glycation end-products (AGEs) formation was evaluated in bovine serum albumin/ribose glycation reaction model. The phytochemical profiles and caffeoylquinic acids (CQAs) contents were determined for the methanolic extract of each plant. Analyzed plant extracts exhibited significant inhibitory activity against key digestive enzymes linked to type II diabetes and obesity. A strong inhibition was observed for glucosidases and mild activity towards amylase and lipase (compared to reference compounds). Moreover, some extracts exhibited potent ability to prevent formation of AGEs, implicated in some diabetic complications. Caffeoylquinic acids were dominant in all plant extracts and findings demonstrate that these compounds are the most relevant hypoglycemic and anti-glycation agents. From the obtained results, Argyranthemum pinnatifidum, Helichrysum melaleucum, and Phagnalon lowei are good candidates for further development of phyto-pharmaceutical preparations as complementary therapy for diabetes and obesity control.The authors are grateful to Francisco Fernandes and Jose Carvalho from Madeira Botanical Garden and to Funchal Ecological Park for the supply and identification of plant material.info:eu-repo/semantics/publishedVersio

Phytochemical Profile, Chemotaxonomic Studies, andIn VitroAntioxidant Activities of Two Endemisms from Madeira Archipelago:Melanoselinum decipiensandMonizia edulis(Apiaceae)

Melanoselinum decipiens and Monizia edulis (Apiaceae) are two endemic plants from Madeira archipelago, phytochemical compositions of which remains little explored, despite their use in folk medicine. Using liquid chromatography with diode array and electrospray ionization/mass spectrometry analysis, their polyphenolic profile was established for the first time. Fifty-six compounds were identified with 5-O-caffeoylquinic acid, quercetin-O-(malonyl)hexoside, luteolin diacetyl, and quercetin-O-hexoside being the major constituents in the leaves of both plant species (≥ 0.76 mg/g of dry extract). Principal component analysis provided a suitable tool to differentiate targeted plants. Naringenin-6,8-di-C-glucoside, quercetin 3-O-pentosylhexoside, and 1,5-O-dicaffeoylquinic acid can be used as discriminatory taxonomic/geographical markers for M. edulis subspecies from Madeira and Porto Santo populations. This methodology of using polyphenols as chemotaxonomic markers proved to be useful for identification of plant species since the results are consistent with previous taxonomical data. The free-radical scavenging activities of the M. decipiens extracts proved to be higher than those of M. edulis, which correlated well with their phenolic content (R2  > 0.906).info:eu-repo/semantics/publishedVersio

Helichrysum monizii Lowe: phenolic composition and antioxidant potential

Introduction – In Madeira Archipelago there are four endemic Helichyrsum species and three of them are used in the traditional medicine. Helichrysum monizii is a rare endemism with very scarce information available concerning its uses in the local traditional medicine. Objective – The aim of this work was to study for the first time Helichrysum monizii in terms of its antioxidant capacity and the identification of the phenolic compounds to which that activity is due. Methodology – Three different methods of extraction were performed and total phenolic and flavonoid contents of extracts were correlated to radical scavenging and antioxidant capacity by DPPH, ABTS, FRAP and β‐carotene assays. An HPLC‐DAD‐ESI/MSn method was employed for the separation and identification of the phenolic and flavonoid components. Results – The results revealed a high antioxidant potential mainly related to the phenolic profile of the plant. Polar components of methanol extracts of Helichrsyum monizii were detected by a high‐performance liquid chromatography/ electrospray ionisation tandem mass spectrometry (HPLC‐DAD‐ESI/MSn ) method. Thirty‐three compounds were identified and 19 of them were identified as quinic acid derivatives.info:eu-repo/semantics/publishedVersio

Antioxidant potential of Artemisia argentea L'Hér alcoholic extract and its relation with the phenolic composition

Artemisia argentea, known as losna or Madeira wormwood is used as aperitif drink with tonic effects. A reversed-phase high-performance liquid chromatography method (RP-HPLC) coupled with diode-array detection (DAD) and electrospray ionization mass spectrometry (ESI/MS) was used for the separation/ characterization of phenolic compounds in A. argentea. A wide variety of components was found, mainly flavonoids (O- and C-glycosylated) and hydroxycinnamic acids derivatives. Five saponins, an uncommon type of compound in Artemisia species, were reported. Quantification of caffeoylquinic acids (CQA) was performed and 5-O-CQA and 3,5-O-diCQA were the major compounds (ca. 300 mg/100 g dried plant). Total phenolic content (TPC) and total flavonoid content (TFC) were established and four assays were used to measure the antioxidant capacity of the plant, revealing a high radical scavenging capacity and a weak reducing potential. Unlike other Artemisia subspecies, A. argentea is totally free of harmful components such as thujene, thujone or artemisia ketone.info:eu-repo/semantics/publishedVersio

Assessing the In Vitro Inhibitory Effects on Key Enzymes Linked to Type-2 Diabetes and Obesity and Protein Glycation by Phenolic Compounds of Lauraceae Plant Species Endemic to the Laurisilva Forest

Methanolic leaf extracts of four Lauraceae species endemic to Laurisilva forest (Apollonias barbujana, Laurus novocanariensis, Ocotea foetens and Persea indica) were investigated for the first time for their potential to inhibit key enzymes linked to type-2 diabetes (α-amylase, α-glucosidase, aldose reductase) and obesity (pancreatic lipase), and protein glycation. Lauraceae extracts revealed significant inhibitory activities in all assays, altough with different ability between species. In general, P. indica showed the most promissing results. In the protein glycation assay, all analysed extracts displayed a stronger effect than a reference compound: aminoguanidine (AMG). The in vitro anti diabetic, anti-obesity and anti-glycation activities of analysed extracts showed correlation with their flavonols and flavan-3-ols (in particular, proanthocyanins) contents. These Lauraceae species have the capacity to assist in adjuvant therapy of type-2 diabetes and associated complications, through modulation of the activity of key metabolic enzymes and prevention of advanced glycation end-products (AGEs) formation.info:eu-repo/semantics/publishedVersio

Uncovering borderline features in a community sample of Portuguese adolescents

Revelando rasgos del trastorno límite de la personalidad en una muestra comunitaria de adolescentes portugueses Resumen. Los rasgos del trastorno límite de la personalidad se pueden identificar en la adolescencia y pueden poseer una expresión psicopatológica. Este estudio pretendió caracterizar los rasgos del trastorno límite de la personalidad en adolescentes portugueses de la población general. La muestra incluyó 1005 adolescentes (586 chicas), Medad =15.35 años. Las chicas presentaron rasgos del trastorno límite más altos que los chicos y no se encontraron diferencias entre los grupos de edad. Los rasgos del trastorno límite más prevalentes fueron sentimientos de abandono e intensidad emocional. Los rasgos del trastorno límite mostraron una correlación negativa con el rendimiento escolar y correlaciones positivas con síntomas psicopatológicos. El modelo de regresión indicó que la impulsividad, la ideación suicida, el estrés y la depresión fueron los predictores significativos de la sintomatología de la personalidad límite. Estos resultados muestran la importancia de evaluar los rasgos del trastorno límite de personalidad en edades tempranas y de la prevención. Palabras clave: Rasgos limite de la personalidad; psicopatología; adolescencia.Abstract: Borderline features can be identified in adolescence and may have a psychopathological expression. This study aimed to characterize borderline features in Portuguese adolescents from the general population. The sample included 1,005 adolescents (586 females), Mage = 15.35 years. Girls presented higher borderline features than boys, and no differences were found between age groups. The more prevalent features were feelings of abandonment and emotional intensity. Borderline features presented a negative correlation with school performance and positive correlations with psychopathological symptoms. The regression model indicated that impulsivity, suicide ideation, stress, and depression were the significant predictors of borderline personality symptoms. These results show the importance of assessing borderline features at an early age and prevention. Keywords: Borderline features; psychopathology; adolescence. Revelando rasgos del trastorno límite de la personalidad en una muestra comunitaria de adolescentes portugueses Resumen: Los rasgos del trastorno límite de la personalidad se pueden identificar en la adolescencia y pueden poseer una expresión psicopatológica. Este estudio pretendió caracterizar los rasgos del trastorno límite de la personalidad en adolescentes portugueses de la población general. La muestra incluyó 1005 adolescentes (586 chicas), Medad =15.35 años. Las chicas presentaron rasgos del trastorno límite más altos que los chicos y no se encontraron diferencias entre los grupos de edad. Los rasgos del trastorno límite más prevalentes fueron sentimientos de abandono e intensidad emocional. Los rasgos del trastorno límite mostraron una correlación negativa con el rendimiento escolar y correlaciones positivas con síntomas psicopatológicos. El modelo de regresión indicó que la impulsividad, la ideación suicida, el estrés y la depresión fueron los predictores significativos de la sintomatología de la personalidad límite. Estos resultados muestran la importancia de evaluar los rasgos del trastorno límite de personalidad en edades tempranas y de la prevención. Palabras clave: Rasgos limite de la personalidad; psicopatología; adolescencia

Phenolic composition and antioxidant capacity of cultivated artichoke, Madeira cardoon and artichoke‐based dietary supplements

Cynara cardunculus var. scolymus (artichoke) and Cynara cardunculus var. ferocissima (Madeira cardoon) are two Asteraceae plants used in Madeira Archipelago in diet and also for medicinal issues. The present work aimed to compare the phenolic composition and quantify the main compounds of these two plants and two artichoke based dietary supplements (juice and dragées). The methanolic extract of the endemic plant cardoon was basi cally composed of caffeoylquinic acid isomers. The same compounds were observed in artichoke extract, where there was a larger number and variety of other phenolic compounds. Variations in qualitative and quantitative composition of the three artichoke based products were extensive, with only 3 components being common to all 3 products. Mono-O-diglycosilated flavonoids (luteolin, apigenin and quercetin) were found in the artichoke products but not in Madeira cardoon. 1,3-O-dicaffeoylquinic acid (cynarin), usually considered mainly responsi ble for the biological properties of artichoke, was found in high amounts ranging in most samples but was not detected in the analyzed commercial dragées. The antioxidant assays results reflected the highly diversified com position of the artichoke-based products, showing a high radical scavenger and reducing capacities, while the ex tract from Madeira cardoon was a poor antioxidantinfo:eu-repo/semantics/publishedVersio