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Phenolic profile and antioxidant activity of Coleostephus myconis (L.) Rchb.f.: an underexploited and highly disseminated species

Publication . Bessada, Sílvia M.F.; Barreira, João C.M.; Barros, Lillian; Ferreira, Isabel C.F.R.; Oliveira, Beatriz

Coleostephus myconis (L.) Rchb.f. (Asteraceae) is a species with ruderal growth and persistence in abandoned soils, being characterized for its plentiful yellow flowering between March and August. Despite its botanical relevance, C. myconis had never been studied neither for its antioxidant activity, nor individual phenolic compounds. Herein, the antioxidant activity of different botanical parts: stems and leaves (green parts), floral buds, flowers in anthesis and senescent flowers, was studied in selected extracts (ethanol, ethanol:water 1:1 and water) through different chemical and biochemical assays. In addition, the phenolic profiles of the hydroethanolic extracts of each botanical part were also characterized by liquid chromatography with dioade array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI/MSn). The antioxidant activity was significantly modulated by the extract type, with the hydroethanolic extracts showing the highest antioxidant activity, especially those obtained from the senescent flowers and floral buds. The phenolic profiles were the same for all flowering stages (with quantitative differences), but that characterized in the green parts was quite different. Floral buds gave the highest contents in phenolic compounds, mainly due to the contribution of 3,5-O-dicaffeoylquinic acid and myricetin-O-methyl-hexoside. Overall, C. myconis showed an interesting potential to be included in different industrial applications.

2016Journal article

Open access

Effects of gamma irradiation in the antimicrobial activity of wild mushroom extracts

Publication . Fernandes, Ângela; Alves, Maria José; Barreira, João C.M.; Antonio, Amilcar L.; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.

The interest of mushrooms has been increasing over time due to their potential in prevention or treatment of different diseases. Mushrooms have been reported for their anticancer, anti-inflammatory, and immunosuppressive and antimicrobial properties. In particular, several authors reported the antibacterial activity of extracts prepared from different mushroom species [1]. In spite of these undeniable qualities, mushrooms are one of the most perishable products and tend to loose quality immediately after harvest. Irradiation is recognized as a safe and effective preservation method, being used worldwide to increase the shelf life of foods (e.g., fruits and vegetables, spices, grains, meat or seafood, aromatic and medicinal plants and spices) [2, 3]. In the present study, the antibacterial properties of methanolic extracts prepared from Boletus edulis Bull. and Hydnum repandum L. Fr., previously submitted to gamma irradiation, were assessed against clinical isolates with different resistance profiles (two Gram negative bacteria: Escherichia coli and Proteus mirabilis, isolated from urine, and two Gram positive bacteria: MSSAmethicillin- sensitive Staphylococcus aureus, isolated from wound exudate and MRSA- methicillin-resistant Staphylococcus aureus, isolated from expectoration) from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal. The fruiting bodies were collected in Trás-os-Montes (Northeast of Portugal) in November 2012. Gamma irradiation was performed in experimental equipment with four 60Co sources at 1 and 2 kGy doses

2015Conference object

Open access

Chemical composition of Boletus pinophilus and Clitocybe subconnexa: preservation with gamma irradiation

Publication . Fernandes, Ângela; Antonio, Amilcar L.; Barreira, João C.M.; Martins, Anabela; Oliveira, Beatriz; Ferreira, Isabel C.F.R.

The short shelf life of mushrooms is a barrier for their distribution and, therefore, there has been extensive research to find technologies that ensure the preservation of mushrooms, maintaining their organoleptic and nutritional properties (1]. Irradiation has proved its technological feasibility to be safely used in the reduction of food losses, being recognized by international organizations as a valid conservation alternative in extending shelflife of many foods. The aim of the present work was to validate the use of 2 kGy dose of gamma radiation to maintain chemical composition of wild mushrooms. Boletus pinophilus Pihit & Dermek and Clitocybe subconnexa Murrill wild samples were obtained in Tnis-os-Montes; subsequently, the samples were divided in two groups: control (non-irradiated, 0 kGy) and irradiated (2 kGy). The irradiation of the samples was performed in a 6°Co experimental chamber. Moisture, protein, fat, carbohydrates and ash were determined following the standard procedures [2]. Free sugars and tocopherols were determined by high performance liquid chromatography coupled to a refraction index detector (HPLC-RI) and a fluorescence detector, respectively; fatty acids were determined by gas-liquid chromatography with flame ionization detection (GC-FID) [3]. The protein and ash content was preserved in both groups, although the sugars and tocopherols decreased in the irradiated samples. Sugars and fatty acids showed significant changes after irradiation treatment, particularly in B. pinophillus, nevertheless, the magnitude of the obtained differences did not seem to be sufficient to affect the chemical profiles of the assayed mushrooms. Overall, the detected chemical changes might be considered as allowable, in view of the high advantages offered by gamma irradiation at decontamination and/or disinfestation level.

2016Conference object

Open access

Chromatographic analysis of antioxidant and related compounds in Polyporus squamosus from different origins

Publication . Fernandes, Ângela; Petrović, Jovana; Stojković, Dejan; Barros, Lillian; Glamočlija, Jasmina; Soković, Marina; Martins, Anabela; Ferreira, Isabel C.F.R.

The antioxidant potential of mushrooms is mainly attributed to their composition in polysaccharides, phenolic compounds, tocopherols and some organic acids [1]. Phenolic compounds contribute directly to the antioxidative action and play an important role in stabilizing lipid peroxidation [2]; exhibit a wide range of bioactive properties such as anti-allergenic, anti-inflammatory and antimicrobial, which have been in part related to their antioxidant activity [3]. Tocopherols are important fatsoluble antioxidants, acting in the cellular membrane; due to their role as scavenger of free radicals protecting human cells against degenerative malfunctions [4]. Some organic acids are very common in natural matrices; malic acid contributes to a pleasantly sour taste and is often used as a food additive; citric acid is known due to its antibacterial and antioxidant properties and fumaric acid is important because of its antioxidant, anti-inflammatory, antimicrobial and acidifying properties [5]. The purpose of the present study was to analyze antioxidant and related compounds (phenolic compounds, tocopherols and organic acids) of Polyporus squamosus (Huds.) Fr. samples originated from two different origins (Portugal and Serbia). Specimens of P. squamosus were collected in Bragança (Northeast Portugal) and Jabučki rit (Northern Serbia) during April 2015 and 2012, respectively. Phenolic compounds, organic acids and tocopherols were determined by high performance liquid chromatograph (HPLC) coupled to a diode array detector (DAD), in the two first cases, and a fluorescence detector in the last one. With respect to phenolic and related compounds, p-hydroxybenzoic and cinnamic acids were identified in both samples; the first one predominates in the sample from Portugal, while cinnamic acid was more abundant in the sample from Serbia. Tocopherols (α-, β and γ-isoforms) were found in the sample from Serbia, but in the sample from Portugal, γ-tocopherol was not identified. This sample showed the highest total tocopherols content, and revealed the highest level of β-tocopherol; γ- tocopherol predominated in the sample from Serbia. Among organic acids, it was possible to quantify oxalic, malic and fumaric acids in both samples. Malic acid was found in higher amounts in the sample from Serbia. Overall, the present study shows that mushroom samples from different origins have dissimilar results, but are both rich in bioactive compounds, being a valuable source for the development of natural medicines and nutraceuticals.

2016Conference object

Open access

Effects of extraction solvent and samples origin in the antitumor and antimicrobial activity of Laurus nobilis L. leaves

Publication . Dias, Maria Inês; Calhelha, Ricardo C.; Barreira, João C.M.; Queiroz, Maria João R.P.; Oliveira, Beatriz; Soković, Marina; Ferreira, Isabel C.F.R.

Laurus nobilis L., commonly known as laurel, belongs to Laureaceae family and it's a native plant from the Mediterranean region. It is mostly appreciated for its flavour as a culinary spice, being also consumed as infusion to treat some gastrointestinal problems [1]. It has been reported as a rich source of bioactive molecules, such as phenolic compounds and essential oils [2, 3]. Due to the exponential increase of oncological diseases and also the increased resistance to antibiotics, there is a growing concern in seeking new sources of antitumors and antimicrobials, being natural matrices such as plants promising sources. Herein, in vitro antitumor (against five different human tumor cell lines) and antimicrobial (antibacterial and antifungal) activities were evaluated on methanolic and aqueous extracts of wild and cultivated L. nobilis leaves. Furthermore, to understand how both bioactive extracts and the origin of laurel sample act differentially towards specific bacterial and fungal species and also selected human tumor cell lines, a statistics analysis was perfonned using two-dimensional prindpal component analysis (PCA). The origin (wild or cultivated) and extract type (methanolic or aqueous) of laurel samples act in a different manner for the same evaluated parameter, showing statistically significant differences in the origin, but not in the extract studied, or vice-versa. It was the extract type who showed most significant changes in the bioactivitjes studied in both laurel samples. From the PCA biplot, it became clear that wild samples were more effective to inhibit tumor cell lines growth. espedally HeLa, MCF7, NCI-H460 and HCT15. It was also observed that methanolic extracts tended to have higher antimicrobial activity, except for Aspergillus niger, Aspergillus. fumigatus and Penicillium verrucosum. The differences in bioactivity might be related to the higher phenolic compounds content (flavonols, flavones and even, total phenolic compounds) found in the methanolic extracts. From the results obtained it is interesting to find out that considering the origin of laurel, wild or cultivated, it was possible to specify the bioactivity of the extract, methanolic our aqueous. Meaning, from the PCA biplot it is possible to choose the combination extract type/origin with potentially highest antitumor or antimicrobial effect, depending on the objective of the study.

2015Conference object

Open access