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

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

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

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

Validation of a HPLC-DAD–ESI/MSn method for caffeoylquinic acids separation, quantification and identification in medicinal Helichrysum species from Macaronesia

The caffeoylquinic acids (CQA) found in Helichrysum species from Madeira Archipelago were identified and quantified. The HPLC-DAD–ESI/MSn method applied was developed and validated showing a good repeatability with recovery values ≥96%. The use of a RP-C18 with a small internal diameter (Ø 3.0 mm) and an acidic mobile phase (acetonitrile and water with 0.1% (v/v) of formic acid) enabled the separation of all compounds within a 30 min analysis. A good resolution between 1,5-O-diCQA and 3,5-O-diCQA isomers, usually hard to separate, was also accomplished. Dicaffeoylquinic acids isomers were the major components among the quantified hydroxycinnamic acids. 1,5-O-diCQA, 3,5-O-diCQA and 5-O-CQA were the compounds found in higher amounts for the different species. The distinct uses of these plants described in the local folk medicine can be related to the phenolic composition.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

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

Phenolic screening by HPLC–DAD–ESI/MSn and antioxidant capacity of leaves, flowers and berries of Rubus grandifolius Lowe

In Madeira Island (Macaronesia Island), Rubus grandifolius Lowe berries, locally known by amoras, are widely consumed fresh or processed as jam, juice or liquor. Folk medicine describes R. grandifolius Lowe fruits and leaves being used to treat diabetes, as depurative, diuretic and to relieve sore throat. The aim of this study was to investigate phenolic composition and antioxidant capacity of the different edible parts of the plant (berries, leaves and flowers). HPLC–DAD–ESI/MSn was used to establish the phe nolic profile. Phenolic monomers such as flavonol O-glycosilated (quercetin and kaempferol), quinic acid and caffeic acid conjugates were characterized using the electrospray source in the negative mode; while positive mode was employed to detect glycosylated anthocyanins (cyanidin, delphinin and petunidin). The berries presented a higher radical scavenger capacity (DPPH and ABTS assays) and reducing prop erties (FRAP) than the leaves and the flowers. Ethanolic extracts showed highest antioxidant capacity when compared with water based extracts: DPPH values of 147.9 ± 0.7 mol eq Trolox/g DM; ABTS value of 255.8 ± 1.9 mol eq Trolox/g DM and FRAP value 9455 ± 29 mmol Fe(II)/mgDM).Mrs. Conceic¸ ão Pires is recognized for excellent assistance in sample collection.info:eu-repo/semantics/publishedVersio