Halophytes: a precious resource of nutritional elements and bioactive compounds

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Unravelling the biotechnological potential of halophyte species from the Algarve coast

Publication . Rodrigues, Maria João da Silva; Custódio, Luísa; Barreira, Luísa; Nogueira, José Manuel Florêncio

This work explored the potential of halophyte plants from the Algarve coast as sources of bioactive compounds with biotechnological applications in the pharmaceutical, food and cosmetic areas. Halophytes are salt-tolerant plants that survive in extreme environments and are equipped with powerful defence mechanisms to manage environmental stress, including the production of bioactive molecules. Despite their enormous potential, halophytes are still quite underexplored regarding their biotechnological applications. This study focused on Frankenia laevis L. (sea-heath), Halopeplis amplexicaulis (Vahl) Ces., Pass. & Gibelli, Juncus acutus L. (spiny rush), J. inflexus L. (wire rush), J. maritimus L. (seaside rush), Limonium algarvense Erben (sea lavender), and Polygonum maritimum L. (sea knotgrass). Methanol and dichloromethane extracts from different plant organs were prepared, evaluated for in vitro antioxidant, antidiabetic, anti-hyperpigmentation and neuroprotective activities, and chemically characterized. Sea lavender and sea knotgrass were selected for their high in vitro antioxidant, neuroprotective, anti-hyperpigmentation and antidiabetic properties, and Juncus species for their in vitro antioxidant and neuroprotective capacities. Sea lavender and sea knotgrass had a high phenolics content, presenting a broad diversity of phenolic acids and flavonoids, respectively. The sea knotgrass had the highest in vitro antioxidant, anti-inflammatory, antidiabetic, neuroprotective and anti-hyperpigmentation properties, closely followed by the sea lavender. Hence, sea lavender and sea knotgrass were selected for experimental production in a greenhouse using different irrigation salinities; freshwater-irrigated plants had the best growth performance and biological properties. Juncunol, a compound isolated from the spiny rush, had in vitro neuroprotective properties, as well as apoptosis-inducing capacity towards hepatocellular carcinoma cells. In conclusion, the halophytes sea lavender, sea knotgrass and spiny rush can be useful sources of bioactive molecules that can potentially help to prevent oxidative stress-related diseases, delay neurodegeneration and hyperpigmentation. The spiny rush is also a promising source of compounds, namely juncunol, with in vitro antihepatocellular carcinoma activity.

2019-11-04Doctoral thesis

Open Access

Isololiolide, a carotenoid metabolite isolated from the brown alga Cystoseira tamariscifolia, is cytotoxic and able to induce apoptosis in hepatocarcinoma cells through caspase-3 activation, decreased Bcl-2 levels, increased p53 expression and PARP cleavage

Publication . Vizetto-Duarte, C; Custódio, Luísa; Gangadhar, Katkam N.; Lago, João Henrique G.; Dias, Catarina; Matos, Ana Marta; Neng, Nuno; Nogueira, José Manuel Florêncio; Barreira, Luísa; Albericio, Fernando; Rauter, Amelia P.; Varela, João

Background: Brown macroalgae have attracted attention because they display a wide range of biological activities, including antitumoral properties. In this study we isolated isololiolide from Cystoseira tamariscifolia for the first time.Purpose: To examine the therapeutical potential of isololiolide against tumor cell lines.Methods/Study design: The structure of the compound was established and confirmed by 1D and 2D NMR as well as HRMS spectral analysis. The in vitro cytotoxicity was analyzed by colorimetric 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide assay in tumoral as well as in non-tumoral cell lines. Cell cycle arrest and induction of apoptosis were assessed by flow cytometry. Alteration of expression levels in proteins important in the apoptotic cascade was analyzed by western blotting.Results: Isololiolidewas isolated for the first time from the brown macroalga C. tamariscifolia. Isololiolide exhibited significant cytotoxic activity against three human tumoral cell lines, namely hepatocarcinoma HepG2 cells, whereas no cytotoxicity was found in non-malignant MRC-5 and HFF-1 human fibroblasts. Isololiolide completely disrupted the HepG2 normal cell cycle and induced significant apoptosis. Moreover, western blot analysis showed that isololiolide altered the expression of proteins that are important in the apoptotic cascade, increasing PARP cleavage and p53 expression while decreasing procaspase-3 and Bcl-2 levels.Conclusion: Isololiolide isolated from C. tamariscifolia is able to exert a selective cytotoxic activity on hepatocarcinoma HepG2 cells as well as induce apoptosis through the modulation of apoptosis-related proteins. (C) 2016 Elsevier GmbH. All rights reserved.

2016-05Journal article

Open Access

A comparative evaluation of biological activities and bioactive compounds of the seagrasses Zostera marina and Zostera noltei from southern Portugal

Publication . Custódio, Luísa; Laukaityte, Simona; Engelen, Aschwin; Rodrigues, Maria Joao; Pereira, Hugo; Vizetto-Duarte, C; Barreira, Luísa; Rodriguez, Hortensia; Albericio, Fernando; Varela, João

This work assessed the antioxidant potential, acetylcholinesterase (AChE) inhibition and the in vitro cytotoxic activity of extracts of the seagrasses Zostera marina and Zostera noltei collected from southern Portugal. The total phenolic contents (TPCs), the rosmarinic acid (RA) concentration (HPLC/DAD) and the fatty acid (FA) profile (GC/MS) are also described. Z. marina had the highest TPC, radical scavenging activity against DPPH radicals and copper chelating activity. Z. noltei had metal chelation capacity to copper and iron ions. None of the species was able to inhibit AChE. Both seagrasses had high levels of polyunsaturated FAs. Z. marina significantly and selectively reduced the viability of tumorous neuronal cells. Z. noltei was highly toxic for the three cell lines tested and was selective against hepatocarcinoma cells at the concentration of 100g/mL. RA was the main compound identified in Z. marina, but not in Z. noltei.

2016-03Journal article

Open Access

Chemical and biological characterization of halophyte plants with ethnopharmacological use in the Algarve coast

Publication . Pereira, Catarina Alexandra Guerreiro; Barreira, Luísa; Custódio, Luísa Margarida Batista; Palomera, Fernando Alberício

This work aimed to investigate the potential of medicinal halophytes as sources of bioactive compounds with health-promoting properties, while validating their traditional uses and searching for new bioactivities/applications. Halophytes are salt-tolerant plants that survive in extreme biotopes and, to cope with environmental stress, are equipped with powerful defence mechanisms, including highly bioactive compounds. Several medicinal halophytes are used in folk therapeutics but, despite their ethnopharmacological importance, are still underexplored. This study focused on five medicinal halophytes from southern Portugal, namely Artemisia campestris L. subsp. maritima Arcangeli (dune wormwood), Crithmum maritimum L. (sea fennel), Eryngium maritimum L. (sea holly), Helichrysum italicum (Roth) G.Don subsp. picardii (Boiss&Reuter) Franco (everlasting), and Plantago coronopus L. (buckshorn plantain). Water and organic extracts were prepared from different plant organs, assessed for in vitro antioxidant, anti-diabetic, anti-hyperpigmentation and anti-protozoan activities, and chemically characterized. The large majority of the extracts have high polyphenolic content and are a potentially good source of these bioactive phytochemicals. They presented a wide diversity of phenolics, especially coumaric, ferulic, syringic, chlorogenic, and p-hydroxybenzoic acids. Minerals were also analysed, and some species may have a nutritional role as mineral supplementary source, particularly sea fennel for macronutrients and dune wormwood for microelements. A preliminary toxicological assessment showed that extracts had overall low toxicity. As for bioactivities, results confirm the strong in vitro antioxidant capacity of the extracts. Everlasting, dune wormwood and sea holly also showed anti-diabetic activity, while dune wormwood had additional anti-hyperpigmentation capacity, and sea fennel had activity against Trypanosoma cruzi. In conclusion, all halophytes can be useful sources of antioxidants to potentially help prevent oxidative-stress related diseases, while everlasting, dune wormwood and sea holly may additionally help control glucose levels. Dune wormwood is also a prospective source of compounds to prevent skin darkening and sea fennel may provide effective anti-T. cruzi molecule(s).

2019-05-23Doctoral thesis

Open Access

Halophytes: Gourmet food with nutritional health benefits?

Publication . Barreira, Luísa; Resek, Eva; Rodrigues, Maria Joao; Rocha, Maria Isabel; Pereira, Hugo; Bandarra, Narcisa; da Silva, Manuela Moreira; J. C. or Varela J. or Varela J.C.S., Varela; Custodio, Luisa

Although little is known about their nutritional composition, Sarcocornia perennis subsp. perennis, S. perennis subsp. alpini and Salicornia ramosissima (Salicorniaceae) as well as Arthrocnemum macro-stachyum (Amaranthaceae) are consumed in gourmet cuisine. In spite of belonging to different families, these halophytes share morphological and organoleptic characteristics. This work explored the nutritional properties and the antioxidant potential of these species using five integrative methods. All species had a nutritional profile suitable for human consumption with high levels of protein (5.20-13.2 g/100 g dw) and n-3 polyunsaturated fatty acids (FA), particularly or alpha-linolenic acid (19.3-25.9% of total FA), and low concentration of toxic metals (below the limits imposed by the European Commission). These halophytes are also a good source of minerals, particularly sodium (64.1-109 mg/gdw), and S. ramosissima is an excellent source of manganese (204 mu g/g dw). However, due care should be taken not to exceed the legal limits for sodium ingestion. These plants showed also significant antioxidant potential, with high radical scavenging activity (RSA), iron reducing power and total phenolics content (20.5-49.2 mg GAE/g). A. macrostachyum had the highest RSA (lC(50-DPPH) = 0.84 mg/mL; IC50-NO = 0.60 mg/mL), and iron reducing potential (IC50= 0.84 mg/mL) along with high levels of alpha- and gamma-tocopherol (8.74 and 4.71 mg/100 g dw, respectively). (C) 2017 Elsevier Inc. All rights reserved.

2017-06Journal article

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