BIOACTIVE PROPERTIES & CYTOPROTECTIVE POTENTIAL OF NATURAL EXTRACTS/INDIVIDUAL COMPOUNDS: APPLICATION OF SINGLE CELL GEL ELECTROPHORESIS AND OTHER BIOCHEMICAL, CHEMICAL AND ELECTROCHEMICAL ASSAYS

Funder

Organizational Unit

Publications

Antioxidants in Pinus Pinaster and mycorrhizal fungi during the early steps of symbiosis

Publication . Carocho, Márcio; Barros, Lillian; Barreira, João C.M.; Ferreira, Isabel C.F.R.; Martins, Anabela

Ectomycorrhizal symbiosis between fungi and the roots of some plants could have important effects in t he levels of antioxidants of both partners [1,2]. In the present work, the effects of eo-culture period (6, 24 and 72 h) in the antioxidant properties and antioxidants production duri ng early steps of in vitro mycorrhization (Pinus pinaster - Pisolithus arhizus and Pinus pinaster - Paxillus involutus) were evaluated. The studied parameters were determined in each culture element (root, mycelium and medium) in order to understand the response of each part ner to the symbiot ic association. The antioxidant properties were determined by assays evaluating free radicals scavenging activi ty, reducing power, ~-ca rotene bleaching inhibition and lipid peroxidation inhibition in animal brain homogenates. The concent rations in phenolics, tocopherols and suga rs were obtained by Folin Ciocalteus assay, HPLC-fluorescence and HPLC-RI, respectively. P. arhizus proved to be more compatible with P. pinaster than P. involutus, since the antioxidant activity in the latter species increased from 48 to 72 h, while P. arhizus antioxidant properties decreased at the same period (less oxidative stress). Despite P. involutus proved to be less suitable to be included in forestation programs using mycorrhization processes, it revealed a higher potential for bioactive compounds production in the early steps of symbiosis. A maximal phenolics content was obtained after the first 6 h and, considering bioactive compounds production purposes, the eoculture should be stopped at t hat time. Tocopherols (except y-tocopherol) contents showed high similarities among culture medium and mycelia. This tendency could not be observed regarding sugars contents, which might indicate that the differences in t he chemical responses that characterize each mycorrhization might be related more directly with sugar (primary metabolites) exchanges.

2012Conference object

Open access

Minerals and vitamin B9 in dried plants vs. infusions: assessing absorption dynamics of minerals by membrane dialysis tandem in vitro digestion

Publication . Dias, Maria Inês; Morales, Patricia; Barreira, João C.M.; Oliveira, Beatriz; Sánchez-Mata, María Cortes; Ferreira, Isabel C.F.R.

Vitamins and mineral elements are among the most important phytochemicals due to their important role in the maintenance of human health. Despite these components had already been studied in different plant species, their full characterization in several wild species is still scarce. In addition, the knowledge regarding the in vivo effects of phytochemicals, particularly their bioaccessibility, is still scarce. Accordingly, a membrane dialysis process was used to simulate gastrointestinal conditions in order to assess the potential bioaccessibility of mineral elements in different preparations of Achillea millefolium (yarrow), Laurus nobilis (laurel) and Taraxacum sect. Ruderalia (dandelion). The retention/passage dynamics was evaluated using a cellulose membrane with 34 mm pore. Dandelion showed the highest levels of all studied mineral elements (except zinc) independently of the used formulations (dried plant or infusion), but yarrow was the only species yielding minerals after the dialysis step, either in dried form, or as infusion. In fact, the ability of each evaluated element to cross the dialysis membrane showed significant differences, being also highly dependent on the plant species. Regarding the potential use of these plants as complementary vitamin B9 sources, the detected values were much lower in the infusions, most likely due to the thermolability effect.

2016Journal article

Open access

Extended use of gamma irradiation in wild mushrooms conservation: validation of 2 kGy dose to preserve their chemical characteristics

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

Irradiation is recognized by international organizations as a conservation technology, and its application to wild mushrooms has been tested in some species. Our research group evaluated the effectiveness of gamma irradiation to conserve different samples of highly appreciated species, particularly, Lactarius deliciosus, Macrolepiota procera, Boletus edulis and Hydnum repandum. From those results and considering also international recommendations on this subject, the 2 kGy dose was chosen for further studies. Therefore, the application of gamma irradiation at 2 kGy dose was extended to Boletus pinophilus Pilát & Dermek and Clitocybe subconnexa Murrill to validate the proposed technology. Considering the obtained results, some of the analysed chemical parameters (specially sugars and fatty acids), as well as the antioxidant activity, showed significant changes after irradiation treatment, particularly in B. pinophillus, probably due to its higher water content. Nevertheless, the obtained differences did not seem to be sufficient to change the organoleptic characteristics of these mushrooms. Furthermore, the antioxidant activity was generally higher in irradiated samples. In conclusion, the detected chemical changes might be considered as acceptable, when considering the high advantages of gamma irradiation at decontamination and/or disinfestation level.

2016Journal article

Open access

Comparative effects of electron beam and gamma radiation on the triacylglycerol profiles of Portuguese chestnuts (Castanea sativa Mill.)

Publication . Barreira, João C.M.; Antonio, Amilcar L.; Carocho, Márcio; Ferreira, Isabel C.F.R.; Kałuska, Iwona; Botelho, M. Luísa; Bento, Albino; Oliveira, Beatriz

CChestnut (Castanea sativa) global production is continuously growing; Portugal produces 20,000 t per year, being 75% of this production concentrated in the Trás-os-Montes region [1]. In order to reach new markets, effective conservation technologies are mandatory, especially since the European Union banned methyl bromide for allegedly being toxic to operators and a severe environment pollutant [2]. Other conservation methods like heat treatment still lack efficiency [3], allowing radiation like γ-irradiation [4] and electron beam [5] to gain interest as an alternative. The main benefits of this technique are related to its low cost, cleanliness and environment friendly. In previous studies of our research group, the effects of different γ and electron beam irradiation doses on the chemical composition and bioactivity of chestnuts were evaluated. Despite the usefulness of those studies, the influence of irradiation on the triacylglycerol composition of chestnut remains undone. Herein, the effects of γ-irradiation and electron beam treatment were studied on chestnut triacylglycerol profiles in fresh and stored samples. The results were classified trough an analysis of variance and a stepwise based linear discrimination analysis as a supervised classification technique, in order to understand entirely the observed changes. Independently of irradiation type, samples irradiated with upper doses showed higher modifications in their triacylglycerol profile. These differences allowed classifying the assayed samples in different groups trough the applied linear discriminant analysis. Hence, triacylglycerol profile might be a realistic indicator of the exact effect of irradiation over chestnuts lipidic fraction, making the stereospecific analysis of TAG very useful to evaluate irradiation consequences.

2012Conference object

Open access

Ergosterol contents in mycorrhizal wild edible mushrooms: comparison by hierarchical cluster analysis

Publication . Barreira, João C.M.; Martins, Anabela; Ferreira, Isabel C.F.R.

Sterols are important molecules of the unsaponifiable fraction in several matrices. In mushrooms, ergosterol, which is an important vitamin D2 precursor, is clearly the main sterol. Hierarchical cluster analysis (HCA) is an unsupervised learning method to standardized data, checking for similarities between sample groups. This method calculates the distances (or correlation) between all samples using a defined metric such as squared Euclidean distance or Chebychev distance. Hierarchical clustering is the most common approach in which clusters are formed sequentially. The most similar objects are first grouped, and these initial groups are merged according to their similarities. Eventually as the similarity decreases all subgroups are fused into a single cluster. Herein, ergosterol was quantified by high performance liquid chromatography, coupled with an ultraviolet detector, in some of the most appreciated mycorrhizal edible mushrooms (Amanita caesarea, Boletus edulis, Cantharellus cibarius, Lactarius deliciosus and Morchella esculenta). Considering fat content (percentage) and ergosterol contents in mg/g fat and mg/100 g of dry weight, two main groups were formed in the HCA: one aggregating A. caesarea and B. edulis and another constituted by C. cibarius, L. deliciosus and M. esculenta. These two groups derived from the higher contents presented by B. edulis and A. caesarea. The detected values indicate that mushrooms might act as a potential source of this vitamin D2 precursor, with special relevance for diets deprived of food products of animal origin.

2013Conference object

Open access