Enma Conde

In vitro antioxidant properties of crude extracts and compounds from brown algae

Research on the bioactives from seaweeds has increased in recent years. Antioxidant activity is one of the most studied, due to the interest of these compounds both as preservatives and protectors against oxidation in food and cosmetics and also due to their health implications, mainly in relation to their potential as functional ingredients. Brown algae present higher antioxidant potential in comparison with red and green families and contain compounds not found in terrestrial sources. In vitro antioxidant chemical methods, used as a first approach to evaluate potential agents to protect from lipid oxidation in foods, confirmed that the brown algae crude extracts, fractions and pure components are comparatively similar or superior to synthetic antioxidants. Particular emphasis on the fucoidan and phlorotannin polymeric fractions is given, considering variations associated with the species, collection area, season, and extraction and purification technologies.

Fractionation of Antioxidants from Autohydrolysis of Barley Husks

The liquid phase from nonisothermal autohydrolysis of barley husks was extracted with ethyl acetate and redissolved in ethanol to yield a crude extract (denoted BHEAE), which was subjected to further processing to enhance the antioxidant activity. A fractionation method, carried out for characterization purposes, consisted of the extraction of BHEAE with organic solvents of increasing polarity and further fractionation in Sephadex LH-20. Among the tested solvents, ethyl acetate allowed the highest yield, phenolic content, and antioxidant activity. Upon elution with methanol, products with high DPPH radical scavenging capacity (IC50 = 0.22 g/L) were obtained. The major compounds in the isolate were benzoic and cinnamic acids. Adsorption-desorption in commercial polymeric resins was carried out as an alternative strategy for BHEAE refining. This method is more suited for possible scale-up and provided a concentrate with a Trolox equivalent antioxidant capacity of 9 mM, which was obtained at a yield of 18 g/kg of barley husks.

Induction of laccase activity in the white rot fungus Pleurotus ostreatus using water polluted with wheat straw extracts

The purpose of this work was to explore the use of polluted water effluents from wheat straw using industries as inducers of lignocellulolytic enzymatic activities in cultures of white rot basidiomycetes. For this purpose, we studied the effect of a wheat straw water extract on the evolution of the laccase activity recovered from submerged cultures of Pleurotus ostreatus made in different media and under various culture conditions. Our results demonstrated an accumulative induction effect in all the cultures and conditions tested. This induction is parallel to changes in the laccase electrophoretic profiles recovered from the culture supernatants. The isoenzyme that appeared to be mainly responsible for the laccase activity under these conditions was laccase 10, as confirmed by sequencing the induced protein. These results support the idea of using wheat straw effluents as inducers in liquid cultures of P. ostreatus mycelia for the production of ligninolytic enzymatic cocktails.

Recovery and Concentration of Antioxidants from Winery Wastes

: Grape and wine byproducts have been extensively studied for the recovery of phenolic compounds with antioxidant activity and a variety of biological actions. The selective recovery and concentration of the phenolic compounds from the liquid phase separated from further diluted winery wastes has been proposed. Adsorption onto non ionic polymeric resins and further desorption with ethanolic solutions was studied. Several commercial food grade resins were screened with the aim of selecting the most suited for the practical recovery of phenolic compounds with radical scavenging activity. Under the optimized desorption conditions (using Sepabeads SP207 or Diaion HP20 as adsorbents and eluting with 96% ethanol at 50 °C) a powdered yellow-light brown product with 50% phenolic content, expressed as gallic acid equivalents, was obtained. The radical scavenging capacity of one gram of product was equivalent to 2–3 g of Trolox.

Purified Phenolics from Hydrothermal Treatments of Biomass: Ability To Protect Sunflower Bulk Oil and Model Food Emulsions from Oxidation

The phenolic fractions released during hydrothermal treatment of selected feedstocks (corn cobs, eucalypt wood chips, almond shells, chestnut burs, and white grape pomace) were selectively recovered by extraction with ethyl acetate and washed with ethanol/water solutions. The crude extracts were purified by a relatively simple adsorption technique using a commercial polymeric, nonionic resin. Utilization of 96% ethanol as eluting agent resulted in 47.0-72.6% phenolic desorption, yielding refined products containing 49-60% w/w phenolics (corresponding to 30-58% enrichment with respect to the crude extracts). The refined extracts produced from grape pomace and from chestnut burs were suitable for protecting bulk oil and oil-in-water and water-in-oil emulsions. A synergistic action with bovine serum albumin in the emulsions was observed.

Cosmetics from Marine Sources

The application of marine resources for the formulation of cosmetics has been known for centuries. Marine organisms produce unique compounds, which are not found in terrestrial sources, to provide protection against hard environmental conditions. They have been used both to confer:

Potential use of Cytisus scoparius extracts in topical applications for skin protection against oxidative damage.

Cytisus scoparius L. is used in folk medicine for the treatment of several ailments in which the antioxidant and anti-inflammatory effects of its carotenoid and flavonoid content is suggested to play an important role. We postulate that flavonoid- and carotenoid-rich extracts from C. scoparius may become useful in the preparation of formulations for topical application to protect the skin against oxidative damage mediated by high energy UV light radiation. The aim of this work was to apply an extraction process to obtain a bioactive extract from C. scoparius for the potential use in topical applications. Aqueous and ethanolic extracts from C. scoparius were characterized for its reducing capacity, radical scavenging capacity, and on the reactive oxygen and nitrogen species (ROS, RNS). The extracts showed activities comparable to that of synthetic antioxidants, and absence of skin-irritant effects at 1%. Those make them good candidates to be used in topical applications as active ingredients.

Selected Process Alternatives for Biomass Refining: A Review

The role of biorefineries in the production of energy and chemicals from biomass of lignocellulosic nature is reviewed. Special attention is devoted to biorefinery schemes dealing with the fractionation of lignocellulosic raw materi- als by chemical treatments. The potential of hydrothermal treatments as the first stage of future biorefineries is discussed. Special attention is devoted to the low-volume, high-added value products that can be solubilized by this type of technol- ogy.

Erythrocytes and cell line-based assays to evaluate the cytoprotective activity of antioxidant components obtained from natural sources.

Oxidative stress can damage cellular components including DNA, proteins or lipids, and may cause several skin diseases. To protect from this damage and addressing consumers appeal to natural products, antioxidants obtained from algal and vegetal extracts are being proposed as antioxidants to be incorporated into formulations. Thus, the development of reliable, quick and economic in vitro methods to study the cytoactivity of these products is a meaningful requirement. A combination of erythrocyte and cell line-based assays was performed on two extracts from Sargassum muticum, one from Ulva lactuca, and one from Castanea sativa. Antioxidant properties were assessed in erythrocytes by the TBARS and AAPH assays, and cytotoxicity and antioxidant cytoprotection were assessed in HaCaT and 3T3 cells by the MTT assay. The extracts showed no antioxidant activity on the TBARS assay, whereas their antioxidant capacity in the AAPH assay was demonstrated. On the cytotoxicity assays, extracts showed low toxicity, with IC50 values higher than 200μg/mL. C. sativa extract showed the most favourable antioxidant properties on the antioxidant cytoprotection assays; while S. muticum and U. lactuca extracts showed a slight antioxidant activity. This battery of methods was useful to characterise the biological antioxidant properties of these natural extracts.

Algal proteins, peptides and amino acids.

Abstract: In this chapter data on the composition of proteins, peptides and amino acids from macro and microalgae are presented. The specific chemical and physicochemical methods of protein and amino acid analysis are discussed. Information on the variability in the contents and activities caused by seasonal and environmental factors is described. In addition, the biological activities and the potential applications as functional food ingredients are discussed.