Hydrophilic and lipophilic fractions, obtained from the marine algae Halimeda incrassata (J.Ellis) J.V.Lamouroux, Halimedaceae, were studied by using the ²-carotene-linoleate assay system. In case of hydrophilic fractions, the total phenolic compounds were quantified and two of their components were identified as salicylic and ferulic acids. From the lipophilic fraction, fatty acid composition was studied. The highest antioxidant activities values were found on the polar fractions containing phenolic acids. The total phenolics content on the hydrophilic fractions was 255 μg of gallic acid equivalents/g of fresh seaweed. To further characterize H. incrassata chemical composition, the total lipid content was quantified (7.4 mg per gram of dried algae) as well as the saturated and unsaturated fatty acids ratio (1:1.46). In summary, this paper adds more convincing evidences in support of the antioxidant abilities of the lyophilized aqueous extract of Halimeda incrassata and it also relates this bioactivity, for the first time, with particular phenolic components of the extract. Altogether, these results represent another step towards the use of this natural product as drug candidates.

An increasing interest has been growing during the past years for the search of natural origin antioxidants, particularly those from marine algae. In this context, the main objective of current research was to evaluate the chemical composition and some antioxidant properties of the aqueous extract of the seaweed Bryothamnion triquetrum. The extracts contains: Proteins (9.5%), Lipids (1.3%), Carbohydrates (5.9%), Fibers (10.2%) and Ashes (43%). In current approach, the following results were obtained for the different procedures assessed: DPPH• radicals scavenging (38% for 4 mg of lyophilized); beta-Carotene-Linoleic assay (12% for 4 mg of lyophilized); O2•- radicals scavenging (IC50 0.36 mg/mL); OH• radicals scavenging (IC50 2.11 mg/mL) and iron quelation ability (IC50 0.37 mg/mL). Thus, antioxidant properties of this natural product seem to be related to its ability to scavenge free species. In previous reports of our group, cinnamic and phenolic acids were proposed as at least partially responsible for the antioxidant properties of the extract, but the necessity for the presence of other components was also shown. Then, the antioxidant properties of the extract could be envisioned as the result of the additive and/or synergic effect between phenolic constituents and the other antioxidant components, such as minerals, carotenes and ascorbic acid.

En la actualidad existe un marcado interés por la búsqueda de antioxidantes de fuentes naturales, incluidas las algas marinas. El objetivo de este trabajo fue evaluar la composición química y propiedades antioxidantes del alga Bryothamnion triquetrum. Se estudió la composición centesimal y de minerales, identificación de ácidos grasos y sustancias antioxidantes. La composición centesimal es la siguiente: Proteínas (9,5%), Lípidos (1,3%), Carbohidratos (5,9%), Fibras (10,2%) y Cenizas (43%). Los resultados de la actividad antioxidante para las diferentes metodologías empleadas fueron: atrapamiento de radicales DPPH• (38%, 4 mg de liofilizado), beta-Caroteno-Linoleico (12%, 4 mg de liofilizado), actividad atrapadora de radicales O2•- (CI50 0,36 mg/mL), de radicales OH• (CI50 2,11 mg/mL) y unión al Fe (CI50 0,37 mg/mL). Las propiedades antioxidantes de esta alga parecen explicarse por la capacidad atrapadora de radicales libres, particularmente relacionada con mecanismos de dismutación de radicales O2•-, inactivación de radicales OH• y quelación de Fe. En trabajos previos se identificaron ácidos cinámicos y fenólicos como moléculas que pudieran explicar la actividad antioxidante, sin embargo adicionalmente se debe considerar un efecto sumatorio y/o sinérgico de otros componentes antioxidantes del extracto, como los descritos en este trabajo, incluidos minerales, carotenoides y vitamina C.

The red crab Pleuroncodes planipes, commonly called "langostilla," is arguably the most abundant benthonic decapod of west coast Mexico, with natural productivity estimated at 735,000 metric tons/year. At the present time, it has not been exploited commercially. The implementation of a new fishery in Mexico, based on the capture of red crab, offers diversification of the fishing industry. In this work a raw extract of langostilla, obtained by mechanical pressing of the whole organism, was analyzed as a potential feed ingredient or additive for cultured marine species. The lyophilized red crab extract possessed: 1) enzymatic activity of proteasa, trypsin, amylase, and lipase; 2) no inhibition of serine-proteases; 3) antioxidant capacity against lipoperoxidation and superoxide ions produced by xanthine oxidase reaction; and 4) activity of insulin-like peptides. The amino acid profile shows high levels of arginine, lysine, and methionine. The chemical score of extract protein was compared with M. japonicus larvae, whole body fish tissue, and short-necked clam tissue. The digestibility of the product was 95% taking purified casein as reference. These biochemical and nutritional characteristics are discussed. These results offer a new use of red crab and the potential of a new fishery in Mexico.

La langostilla roja Pleuroncodes planipes es posiblemente el decápodo bentónico más abundante de la costa oeste de México, con una productividad natural estimada en 735,000 toneladas métricas al año, sin embargo este recurso aún no ha sido explotado comercialmente. En este trabajo el extracto crudo de la langostilla, obtenido por prensado mecánico del organismo completo, es analizado como un ingrediente potencial o aditivo alimentario para la nutrición de especies marinas en cultivo. El extracto liofilizado de la langostilla demostró poseer i) actividad enzimática digestiva de proteasas, amilasas y lipasas, ii) ausencia de inhibición de proteasas de tipo serínico, iii) actividad antioxidante hacia la lipoperoxidación de tejido cerebral de rata y de los iones superóxido producidos por la reacción de la xantina-oxidasa, iv) actividad de péptidos tipo insulina. El perfil de aminoácidos presentó niveles altos de arginina, lisina y metionina. El cómputo químico de la proteína del extracto fue comparada con proteína de larva M. japonicus, tejido completo de pescado y de almeja. La digestibilidad del producto fue de 95.7% tomando la caseína purificada como referencia. Estas características bioquímicas y nutricionales y su relevancia se discuten en el trabajo. Estos resultados abren la perspectiva de la captura de langostilla como una nueva actividad pesquera en México.