J. M. Ezquerra-Brauer

Bioactive Peptides and Depsipeptides with Anticancer Potential: Sources from Marine Animals

Biologically active compounds with different modes of action, such as, antiproliferative, antioxidant, antimicrotubule, have been isolated from marine sources, specifically algae and cyanobacteria. Recently research has been focused on peptides from marine animal sources, since they have been found as secondary metabolites from sponges, ascidians, tunicates, and mollusks. The structural characteristics of these peptides include various unusual amino acid residues which may be responsible for their bioactivity. Moreover, protein hydrolysates formed by the enzymatic digestion of aquatic and marine by-products are an important source of bioactive peptides. Purified peptides from these sources have been shown to have antioxidant activity and cytotoxic effect on several human cancer cell lines such as HeLa, AGS, and DLD-1. These characteristics imply that the use of peptides from marine sources has potential for the prevention and treatment of cancer, and that they might also be useful as molecular models in anticancer drug research. This review focuses on the latest studies and critical research in this field, and evidences the immense potential of marine animals as bioactive peptide sources.

Antimutagenicity and Antiproliferative Studies of Lipidic Extracts from White Shrimp (Litopenaeus vannamei)

An organic extract from fresh shrimp (Litopenaeus vannamei) was studied for antimutagenic and antiproliferative properties using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. Shrimp extract was sequentially fractionated by thin layer chromatography (TLC) and each fraction was tested for antimutagenic and antiproliferative activities. Crude organic extracts obtained from shrimp reduced the number of revertants caused by aflatoxina B1, showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. These results suggested that the lipid fraction of the tested species contained compounds with chemoprotective properties that reduce the mutagenicity of AFB1 and proliferation of a cancer cell line.

Producción y evaluación funcional de un concentrado proteico de calamar gigante (Dosidicus gigas) obtenido mediante disolución alcalina Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) obtained by alkaline dissolution

A protein concentrate from jumbo squid (Dosidicus gigas) was produced under alkaline conditions. Solubility, recovery of proteins, electrophoretic profile, as well as changes in the pattern of solubility of proteins recovered were determined. In the gels, its capability (functional–technological) was evaluated in terms of texture profile analysis, folding test, water holding capacity, and color attributes. The alkaline treatment promoted the autolysis of myosin heavy chain; however, the alkaline concentrate showed better gel formation ability compared with the mantle, resulting in gel strength of 11.83 ± 0.66 and 21.53 ± 2.95 N · cm at 75% and 90% compression, respectively. Nevertheless, the gels prepared from protein concentrate showed a low water holding capacity (38.1 ± 0.1%), while the folding test showed gels grade C-A and C-B for protein concentrate and mantle, respectively. Se elaboró un concentrado proteico a partir de calamar gigante (Dosidicus gigas) bajo condiciones alcalinas. Se monitoreó la solubilidad, recuperación de proteínas, el perfil electroforético, así como cambios en el patrón de solubilidad de las proteínas recuperadas. En los geles se evaluó su capacidad funcional-tecnológica en términos de su análisis del perfil de textura, prueba de doblado, capacidad de retención de agua y los atributos de color. El tratamiento alcalino promovió la autolisis de la cadena pesada de miosina; sin embargo el concentrado alcalino mostró una mejor capacidad de formación de geles en comparación con el manto, obteniéndose fuerzas de gel de 11,83 ± 0,66 y 21,53 ± 2,95 N · cm en compresiones al 75% y 90%, respectivamente. No obstante los geles elaborados a partir del concentrado proteico mostraron una pobre capacidad de retención de agua (38,1 ± 0,1%), mientras que la prueba de doblado mostró geles grado C-A y C-B para concentrado proteico y manto, respectivamente.

Bioactive Lipidic Extracts from Octopus (Paraoctopus limaculatus): Antimutagenicity and Antiproliferative Studies.

Fractions from an organic extract from fresh octopus (Paraoctopus limaculatus) were studied for biological activities such as antimutagenic and antiproliferative properties using Salmonella tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. A chloroform extract obtained from octopus tentacles was sequentially fractionated using thin layer chromatography (TLC), and each fraction was tested for antimutagenic and antiproliferative activities. Organic extract reduced the number of revertants caused by aflatoxin B1 showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. Based on the results obtained, the isolated fractions obtained from octopus contain compounds with chemoprotective properties that reduce the mutagenicity of AFB1 and proliferation of cancer cell lines.

Methods to obtain protein concentrates from jumbo squid (Dosidicus gigas) and evaluation of their functionality

Jumbo squid is an important fishery resource in Mexico, and its muscle is lean and white and it has a very low price in the market. It is abundant, but with little or nothing added value, therefore is necessary to search alternatives of processing. Due to muscle characteristics, the aim of this study was to obtain protein concentrates using different methods. They were obtained by means of acidic (acid protein concentrates) and alkaline (alkaline protein concentrates) dissolution. Moreover, a protein concentrate was obtained by direct isoelectric precipitation and by the traditional method (neutral protein concentrates). The yield with better results was alkaline protein concentrates (63.58 ± 1.8%). The gel hardness was significantly different (p < 0.05), especially for the alkaline protein concentrates. The acid protein concentrates, isoelectric precipitation and alkaline protein concentrates were better with regard to the neutral protein concentrates, concerning the emulsifying and foaming properties. The protein concentrates by means of alkaline dissolution gave a better gelling property, but all the processes had the potential to obtain protein with emulsifying and foaming properties.

Effects of Fumonisin B1-Containing Feed on the Muscle Proteins and Ice-Storage Life of White Shrimp (Litopenaeus vannamei)

Juvenile (5.5–5.7 g) white leg shrimp were exposed to mycotoxin in one indoor trial by feeding fumonisin B1 (FB1) at levels from 0.2 to 2.0 μg g−1 FB1 for 30 days. Shrimp growth was affected after exposure to more than 0.6 μg g−1 FB1. Soluble muscle protein concentration decreased, and changes in myosin thermodynamic properties were observed in shrimp after 30 days of exposure to FB1. Marked histological changes in tissue of shrimp fed a diet containing FB1 at 2.0 μg g−1 were also observed. Shrimp fed diets containing more than 0.6 μg g−1 FB1 showed greater decrease in shear forces after 12 days of ice storage.

Aislamiento y caracterización parcial de miosina del manto de calamar gigante (Dosidicus gigas)

In the present work the myosin molecule from jumbo squid mantle (Dosidicus gigas) was isolated and characterized with the aim to evaluate the influence of ionic strength on its gelling properties. It was found that the myosin molecule possesses different chemical and structural characteristics than other vertebrates and invertebrates species, such as some cephalopods, which might explain differences in gelation in comparison to those from other organisms. A lower content of total sulfhydryl groups (TSH) possibly caused an improvement in the myosin molecule flexibility when the ionic strength increased (p ˂ 0.05). The aforementioned possibly affected (p ˂ 0.05) the enzyme activity, surface hydrophobicity, viscosity and RSH groups. The results demonstrate that the myosin molecule from jumbo squid is structurally different from the rest of the marine species.

Caracterización de hidrolizados de desechos de calamar gigante (Dosidicus gigas) obtenidos por autohidrólisis y un proceso químico-enzimático

Se compararon los hidrolizados obtenidos de los subproductos del calamar gigante (cabeza, tentáculos, piel y mezcla) aplicando dos procesos, autohidrólisis (55°C, pH 5,0 y proteasas endógenas) y químico-enzimático (45°C, pH 2,5 y pepsina), mediante el análisis de proteína soluble (PS), grado de hidrólisis (GH) por el método de ortoftaldehído y por el coeficiente de degradación de proteína (CDP) obtenido por la integración de la información del análisis de la imagen de los geles de SDS-PAGE. En la mezcla de subproductos se analizó el perfil de aminoácidos e hidrofobicidad (SoANS) del hidrolizado. Los valores más altos de PS, GH y CDP lo presentaron los hidrolizados de la cabeza, en ambos procesos. La piel requirió más tiempo para hidrolizarse. Los hidrolizados por autohidrólisis presentaron mayor contenido de aminoácidos y SoANS. La actividad enzimática endógena en subproductos ofrece una alternativa económica para aprovechar la cabeza, tentáculos y piel del calamar gigante.

Collagen from jumbo squid fin: extracting conditions and influence of the protease system on collagen hydrolysate antioxidant activity

The optimal alkaline and acid conditions for insoluble collagen extraction from jumbo squid fin (JSF) were established by factorial analysis. Dependent variable: protein concentration; independent variables: NaOH and HCl concentrations. The antioxidant properties of JSF collagen hydrolysates obtained by two protease systems were studied. Moreover, jumbo squid skin (JSS) collagen was obtained and hydrolysated under optimal conditions. The optimal extraction condition was 0.5 M NaOH followed by 0.2 M HCl. Collagen α-chains were detected in both JSF and JSS. Collagen β-component was detected only in JSS. JSS collagen showed higher levels of polar and hydrophobic amino acids. The JSF hydrolysates produced by subtilisin showed a lower degree of hydrolysis and higher antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity-fluorescein (ORACFL)) than those produced by a mixture of trypsin, chymotrypsin, and peptidase. The JSS hydrolysates showed a higher antioxidant capacity. We have thus established a suitable process to improve the utility of JSF.

Preparation of chitosan matrices with ferulic acid: physicochemical characterization and relationship on the growth of Aspergillus parasiticus

ABSTRACT Antioxidant, anticarcinogenic, and antimicrobial properties have been reported for ferulic acid (FA), therefore, its application interests both food and agriculture research. FA was immobilized in different chitosan (CS) matrices, physicochemicaly characterized and the effect on Aspergillus parasiticus ecological parameters evaluated. Nanoparticles (Nparticles), microparticles (Mparticles) and microcapsules (Mcapsules) of 35–40 nm, 30–40 μm, and 20 μm, respectively were obtained; FA incorporation in matrices affected their morphology, physicochemical properties, and their fungistatic effect. The effect of the particles was dependent on the matrix exposed. Nparticles and Mparticles showed high FA immobilization efficiency as well as a good fungistatic effect against A. parasiticus: Radial growth at 168 h was 28.46 ± 1.01 and 28.84 ± 1.36 and the inhibition of spore germination at 30 h was 57.44 ± 0.22 and 55.74 ± 2.19, for Nparticles and Mparticles, respectively compared with control cultures. Abnormalities in mycelium, hyphae, and spores morphology were observed, as well as low sporulation due particle interaction with the fungus.