The marine environment represents a relatively untapped source of functional ingredients that can be applied to various aspects of food processing, storage, and fortification. Moreover, numerous marine-based compounds have been identified as having diverse biological activities, with some reported to interfere with the pathogenesis of diseases. Bioactive peptides isolated from fish protein hydrolysates as well as algal fucans, galactans and alginates have been shown to possess anticoagulant, anticancer and hypocholesterolemic activities. Additionally, fish oils and marine bacteria are excellent sources of omega-3 fatty acids, while crustaceans and seaweeds contain powerful antioxidants such as carotenoids and phenolic compounds. On the basis of their bioactive properties, this review focuses on the potential use of marine-derived compounds as functional food ingredients for health maintenance and the prevention of chronic diseases.

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The term 'nanoclay' generically refers to the natural clay mineral, montmorillonite, with silica and alumina as the dominant constituents. The incorporation of nanoclays into polymeric systems dramatically enhances their barrier properties as well as their thermal and mechanical resistance. Consequently, nanoclays are employed in a wide range of industrial applications with recent studies reporting potential use in the modulation of drug release. With the increase in manufacturing of nanoclay-containing products, information on the toxicological and health effects of nanoclay exposure is warranted. Thus, the objective of the present study was to evaluate the cytotoxicity of two different nanoclays: the unmodified nanoclay, Cloisite Na+ ®, and the organically modified nanoclay, Cloisite 93A®, in human hepatoma HepG2 cells. Following 24 h exposure the nanoclays significantly decreased cell viability. Cloisite Na+ induced intracellular reactive oxygen species (ROS) formation which coincided with increased cell membrane damage, whilst ROS generation did not play a role in Cloisite 93A-induced cell death. Neither of the nanoclays induced caspase-3/7 activation. Moreover, in the cell culture medium the nanoclays aggregated differently and this appeared to have an effect on their mechanisms of toxicity. Taken together, our data demonstrate that nanoclays are highly cytotoxic and as a result pose a possible risk to human health.

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Nanoparticle cytotoxicity testing based on in vitro methods frequently lack consistency. Even the inclusion of the commonly employed growth supplement, FCS (fetal calf serum), generates variable results. Thus, our object was to investigate the effect of FCS concentration on the cytotoxic behaviour of the unmodified nanoclay, Cloisite® Na(+). Human monocytic U937 cells in medium supplemented with 5% FCS, 2.5% FCS or serum-free medium were treated with 1 mg/ml Cloisite Na(+). Cell growth in 2.5% FCS was significantly inhibited by Cloisite Na(+) within 48 h, whereas little effect was seen with a supplement of 5% FCS. Without serum, cell growth was inhibited and Cloisite Na(+) had a detrimental effect on these cells. In media supplemented with FCS, the nanoclays agglomerated together to form large bundles, whereas they were evenly dispersed throughout the medium in the absence of serum. Clay particles, therefore, have cytotoxic properties that may be linked to their dispersion pattern. These adverse effects seem to be masked by 5% FCS. Serum supplementation is an important consideration in the toxicological assessments of nanomaterials on cells, which needs to be addressed in the standardization of in vitro testing methods.