Proposal of a method for fluorimetric analysis of malvin in red wines

A fluorimetric method for the quantitative determination of malvin (malvidin 3,5-diglucoside) in red wines is described. The method is based on previous fractionation of the wine in a Polyclar AT column and later formation of a fluorophore, by oxidation of the malvin. The proposed method has good precision and accuracy and when applied to hybrid red wines affords results significantly comparable with those obtained by HPLC

Leaves and decoction of Juglans regia L.: Different performances regarding bioactive compounds and in vitro antioxidant and antitumor effects

Juglans regia L. (walnut) leaves are considered a source of healthcare compounds, and have been widely used in traditional medicine. Furthermore, they have been reported as a source of bioactive molecules such as the antioxidant phenolic compounds. In the present study, organic acids, mono and oligosaccharides, and tocopherols were analyzed in leaves and decoction (widely used for topical applications). Furthermore, the phenolic composition and bioactivity of walnut leaves was determined in its decoction and methanol extract. Malic acid, sucrose, alpha-tocopherol and 3-O-caffeoylquinic acids and quercetin O-pentoside were the most abundant organic acid, disaccharide, tocopherol isomer and phenolic compounds, respectively. Methanol extract presented higher antioxidant and antitumor potential than decoction; both samples did not show toxicity for non-tumor liver primary cells. This study provides a more complete characterization of phenolic compounds of walnut leaves, and as far as we know, this is the first time that the presence of procyanidins and taxifolin derivatives, as also tocopherols were reported in J. regia leaves.The authors are grateful to Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). L. Barros and R.C. Calhelha also thank to FCT, POPH-QREN and FSE for their grants (SFRH/BPD/4609/2008 and SFRH/BPD/68344/2010, respectively). The GIP-USAL is financially supported by the Spanish Government through the Consolider-Ingenio 2010 Programme (FUN-C-FOOD, CSD2007-00063). M. Duenas thanks the Programa Ramon y Cajal for a contract

Changes in the detailed pigment composition of red wine during maturity and ageing

[EN] The qualitative and quantitative changes produced, during maturation and ageing, in the pigment composition of a red wine made from Vitis vinifera cv Tempranillo grapes have been studied. In order to determine the detailed composition of the main pigment families involved in the colour changes, a fractionation of the samples has been carried out. One-hundred and twenty-nine different compounds have been identified and their evolutions with wine age have also been established. The data obtained in the analyses of the fractions by high performance liquid chromatography–diode array detection coupled to mass spectrometry (HPLC–DAD–MS) have been used in pigment identification. In order to confirm the identity of some of these compounds, their syntheses have also been carried out. As far as we know, compounds originated by acylation of the monoglucosides of the anthocyanins with lactic acid as well as 3,7-diglucosides of anthocyanins have, among others, been reported here for the first time. The moments of appearance and disappearance of all the detected compounds have also been established as well as the changes in the levels of the different pigment families and subfamilies originated as a consequence of maturation and ageing of the wine in barrels or in bottles. As wine became older, the percentages of anthocyanins decreased slightly, whereas that of the anthocyanin-derived pigments increased and, above all, compounds providing the wine with orange hues (pyranoanthocyanins). In the last sample, they represented 70% of the anthocyanin-derived pigments. On the contrary, the percentage of compounds providing bluish hues to the wine, direct and acetaldehyde-mediated flavanol–anthocyanin condensation products, decreased. This change in the nature of the anthocyanin-derived pigmentwould explain the colour change observed in the samples, from purple towards orange hues

Separation of pyranoanthocyanins from red wine by column chromatography

[EN] With the aim of monitoring the formation of anthocyanin-derived pigments and contributing to the study of their chromatic properties, stability and relative contribution to the colour of red wines, a method for fractionation of the colouring material was set up. The method was based on the distinct reactivity of the different pigment families towards bisulfite (hydrogen sulfite). The wine, acidified and bleached with NaHSO3, was placed in a Toyopearl® HW-40(s) gel column and submitted to elution with ethanol. Two fractions with different pigment compositions were collected and analysed by liquid chromatographay diode array detection-mass spectrometry. Compounds present in each fraction were identified according to their UV-visible and MSn mass spectra, showing that the first one was mostly constituted of pyranoanthocyanins, whereas the second basically contained anthocyanins and anthocyanin-flavanol condensation products. A large variety of new pigments were detected, some of which had not been previously reported in red wines, as far as we know. Characteristic MS2 and MS3 fragmentation patterns were observed within each family of compounds, which could be further applied for characterisation of unknown pigments in other wines

Chemical characterization and bioactive properties of Geranium molle L.: from the plant to the most active extract and its phytochemicals

After a period of indifference, in which synthetic compounds were favored, there is an increasing interest in the study of the biological properties of plants and the active principles responsible for their therapeutic properties. Geranium molle L. has been used in the Portuguese folk medicine for the treatment of various ailments including cancer but, unlike many of the species from the Geranium genus, its phytochemical characterization and biological activity are virtually unexplored. In this study a G. molle sample from Trás-os-Montes, north-eastern Portugal, was chemically characterized regarding nutritional value, free sugars, organic acids, fatty acids and tocopherols, and several aqueous (decoction, infusion) and organic (n-hexane, dichloromethane, ethyl acetate, acetone, methanol) extracts of the plant were assessed for their bioactive properties. The antioxidant activity was evaluated by means of the free radicals scavenging activity, reducing power and inhibition of lipid peroxidation. The cytotoxicity of the different extracts was assessed in vitro against several human cancer cell lines (breast, lung, cervical and hepatocellular carcinomas) and, additionally, their hepatotoxicity was evaluated using a porcine liver primary cell culture. G. molle was shown to be rich in carbohydrates and proteins, providing tocopherols and essential fatty acids. Amongst the various extracts, the acetone extract was found to have the highest content of phenolic compounds (mainly ellagitannins, but also some flavone and flavonol glycosides) as well as the highest antioxidant and cytotoxic activities. To the best of our knowledge, this is the first report on the chemical composition and bioactive properties of G. molle.This work is supported by national funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013 and PEst-OE/AGR/UI0690/2014. V.C. Graça, M.I. Dias, R.C. Calhelha and L. Barros thank FCT for SFRH/BD/52542/2014, SFRH/BD/84485/2012, SFRH/BPD/68344/2010 and SFRH/BPD/107855/2015 grants, respectively

Antifungal activity against Candida species and phenolic characterization of decoction, infusion and hydroalcoholic extract of cultivated Salvia officinalis L.

The frequency and severity of diagnosed fungal infections is growing and, linked with this, it is observed an exacerbated increase of the antifungal drugs resistance. Candida albicans has been considered the main agent responsible for opportunistic pathogenic infections, but, recently, other non-Candida albicans Candida species have also been considered [1]. In face to the increased number of Candida species drug resistant, it is crucial to use natural matrices to discover efficient alternative therapies to current antifungal agents. Salvia officinalis L., commonly known as sage, could be one of those natural matrices, containing a wide variety of bioactive molecules. Despite the existence of some reports on antimicrobial activity of sage, the most studied preparation is the essential oil, being scarce the aqueous extracts. The antifungal activity of decoction, infusion and hydroalcoholic extract of cultivated sage were evaluated, and further characterized in terms of phenolic composition (HPLC–DAD–ESI/MS). Antifungal activity was assessed against a total of 19 Candida strains of C. albicans, C. tropicalis, C. parapsilosis and C. glabrata recovered from different human biological samples. The most pronounced effect was observed against C. parapsilosis, followed by C. tropicalis and C. albicans. No effect was observed against the three C. glabrata strains. In general, decoction presented the most pronounced effect, followed by infusion and hydroalcoholic extract, varying directly according with the extract concentration. Decoction also showed the highest concentration in phenolic compounds, followed by hydroalcoholic extract and infusions. Rosmarinic acid and luteolin 7-O glucuronide were the main phenolic compounds. Thus, the use of sage decoction, incorporated on daily food dietary, or even as complement to an antifungal therapy, could provide considerable benefits, not only by internal but also external use, without the common side effects reported for essential oil

Characterization and quantification of phenolic compounds in four tomato (Lycopersicon esculentum L.) farmer’ varieties in Northeastern Portugal homegardens.

Tomato (Lycopersicon esculentum L.) is one of the most widely consumed fresh and processed vegetables in the world, and contains bioactive key components. Phenolic compounds are one of those components and, according to the present study, farmers’ varieties of tomato cultivated in homegardens from the northeastern Portuguese region are a source of phenolic compounds, mainly phenolic acid derivatives. Using HPLC-DAD-ESI/MS, it was concluded that a cis p-coumaric acid derivative was the most abundant compound in yellow (Amarelo) and round (Batateiro) tomato varieties, while 4-O-caffeolyquinic acid was the most abundant in long (Comprido) and heart (Coração) varieties. The most abundant flavonoid was quercetin pentosylrutinoside in the four tomato varieties. Yellow tomato presented the highest levels of phenolic compounds (54.23 μg/g fw), including phenolic acids (43.30 μg/g fw) and flavonoids (10.93 μg/g fw). The phenolic compounds profile obtained for the studied varieties is different from other tomato varieties available in different countries, which is certainly related to genetic features, cultivation conditions, and handling and storage methods associated to each sample

The influence of electron beam radiation in the nutritional value, chemical composition and bioactivities of edible flowers of Bauhinia variegata L. var. candida alba Buch.-Ham from Brazil

As edible flowers are highly perishable, irradiation technology can be applied to increase their shelf life, as also for phytosanitary purposes. Herein, flowers of Bauhinia variegata L. var. candida alba Buch.-Ham were submitted to electron beam irradiation at the doses of 0.5, 0.8 and 1 kGy, to study the effects in the nutritional and chemical profiles, and also in antioxidant, cytotoxic and anti-inflammatory activities. The petals of white flowers revealed interesting bioactive properties being kaempferol derivatives the most abundant compounds, especially kaempferol-3-O-rutinoside. The applied irradiation doses did not highly affect the nutritional profile. No changes were produced in cytotoxicity, but the anti-inflammatory activity slightly decreased. However, the antioxidant activity was increased, especially in the dose of 0.5 kGy, in agreement with the higher content in phenolic compounds found at this dose.info:eu-repo/semantics/publishedVersio

Color and Stability of Pigments Derived from the Acetaldehyde-Mediated Condensation between Malvidin 3-O-Glucoside and (+)-Catechin

[EN] A pigment derived from the acetaldehyde-mediated condensation between (+)-catechin and malvidin 3-O-glucoside has been prepared and isolated by semipreparative HPLC, and its characteristics of color and stability have been studied and compared with that of malvidin glucoside in aqueous solutions. When the pH was increased from 2.2 to 5.5, the solution of the pigment became progressively more violet (ìmax ) 560 nm at pH 5.5), whereas similar solutions of the anthocyanin were almost colorless at pH 4.0. This behavior indicated that the anthocyanin moiety of the pigment was more protected against water attack, and thus the formation of its quinonoidal forms was favored. The color of the pigment also showed more stability with regard to bleaching by SO2 than that of malvidin glucoside. Nevertheless, the pigment was more sensitive to degradation in aqueous solution than the anthocyanin. The cleavage of the ethyl bridge that links the anthocyanin and the catechin constituted the first step in its degradation, as demonstrated by the formation of malvidin glucoside as a major product

Decoction, infusion and hydroalcoholic extract of cultivated thyme : antioxidant and antibacterial activities, and phenolic characterisation

Bioactivity of thyme has been described, but mostly related to its essential oils, while studies with aqueous extracts are scarce. Herein, the antioxidant and antibacterial properties of decoction, infusion and hydroalcoholic extract, as also their phenolic compounds, were evaluated and compared. Decoction showed the highest concentration of phenolic compounds (either phenolic acids or flavonoids), followed by infusion and hydroalcoholic extract. In general, the samples were effective against gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and gram-negative (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Enterococcus aerogenes, Proteus vulgaris and Enterobacter sakazakii) bacteria, with decoction presenting the most pronounced effect. This sample also displayed the highest radical scavenging activity and reducing power. Data obtained support the idea that compounds with strong antioxidant and antibacterial activities are also water-soluble. Furthermore, the use of thyme infusion and decoction, by both internal and external use, at recommended doses, is safe and no adverse reactions have been described.The authors are grateful to Foundation for Science and Technology (FCT, Portugal) for N. Martins grant (SFRH/BD/87658/2012), L. Barros researcher contract under "Programa Compromisso com Ciencia - 2008" and financial support to the research center CIMO (strategic project PEst-OE/AGR/UI0690/2011)