No abstract

Protein hydrolysates were prepared from echinoderm byproducts, including viscera (SCV) of Atlantic sea cucumber (Cucumaria frondosa) and digestive tract (UDT) and non-commercial grade gonads (UGN) of green sea urchin (Strongylocentrotus droebachiensis). Enzymatic hydrolysis was performed on defatted materials using Alcalase Ò 2.4L (0.75% w ⁄ w) and reaction was carried out overnight ($16 h, 55°C, pH 8.0). Freeze-dried hydrolysates were analysed for their nutritional composition, nitrogen solubility index and antioxidant activity. Degree of hydrolysis was low, with values of 5.6%, 4.6% and 7.0% for SCV, UDT and UGN, respectively. Hydrolysates showed high protein content ($55%), high proportion of essential amino acids ($35% of total amino acids) and good solubility (nitrogen solubility index % 68%). They contained variable concentrations of major and trace elements with a predominance of Na and K. Hydrolysates showed apparent antioxidant activities in both ORAC assay (267-421 lmol TE g )1 ) and inhibition of lipid oxidation test (54-57%). Antioxidant activities were thought to be associated with the presence of antioxidant peptides in hydrolysates. Our results showed that hydrolysates from Atlantic sea cucumber and green sea urchin byproducts might serve as alternative sources of dietary proteins, with good nutritional composition, high solubility and interesting protection against oxidative stress.

Fucoxanthin is a carotenoid present in the chloroplasts of brown seaweeds. When ingested, it is metabolized mainly to fucoxanthinol in the gastrointestinal tract by digestive enzymes. These compounds have been shown to have many beneficial health effects. The present study was designed to evaluate the molecular mechanisms of action of fucoxanthin and/or of its metabolite fucoxanthinol against viability of estrogen-sensitive MCF-7 and estrogen-resistant MDA-MB-231 breast cancer cell lines. Fucoxanthin and fucoxanthinol reduced the viability of MCF-7 and MDA-MB-231 cells in dose- and time-dependent manners as a result of increased apoptosis. Furthermore, fucoxanthinol-induced apoptosis was more potent than that of fucoxanthin and correlated, for MDA-MB-231 cells, with inhibitory actions on members of the NF-κB pathway p65, p50, RelB, and p52. Being overexpressed and regulated by NF-κB in different types of cancers, the transcription factor SOX9 was also decreased at the nuclear level by fucoxanthin and fucoxanthinol in MDA-MB-231. Taken together, the current results suggest that fucoxanthinol and fucoxanthin could be potentially effective for the treatment and/or prevention of different types of cancers, including breast cancer.

No abstract

Proximate composition, amino acid and fatty acid profiles, and mineral and vitamin contents of by-products from Atlantic sea cucumber (Cucumaria frondosa) and green urchin (Strongylocentrotus droebachiensis) processing plants were investigated. Results showed that sea cucumber viscera, urchin digestive tract (UDT) and non-commercial grade gonads contained 4.5-14.4% total proteins and 1.9-4.6% lipids (wet weight basis). They were rich in essential amino acids with values of about 36% of total amino acids. Samples were also rich in polyunsaturated fatty acids (44% of total fatty acids) and showed high content in EPA (17% of total fatty acids), but low DHA level (0.2%) was observed. In terms of vitamins content, UDT showed highest retinol and alpha-tocopherol contents when compared to other marine samples. Results showed that by-products from echinoderm processing plants contain various nutritious components with levels generally comparable even better than their edible counterparts, and efforts should be invested to valorise these biological wastes in a world context of rarefaction of nutritional marine resources.