Composición bioquímica y potencial antioxidante del pepino del mar Mediterráneo comestible Holothuria tubulosa

The sea cucumber or holothurian is a marine species which has been prized in some Asian coun­tries for its nutritional qualities. The purpose of this work was to study the biochemical composition and free radical scavenging and antioxidant activities of Holothuria tubulosa tegument from the Bizerta lagoon in north­ern Tunisia. The obtained data demonstrated that the extract of sea cucumber teguments exhibited high bio­chemical levels (such as moisture 80.77%, protein 7.07%, lipids 10.21%, energy value 13.64 Kcal/g ww), and an important nutritional value (including n-3/n-6: 2.11, EPA+DHA: 20.96, AI: 1.38 and TI: 0.54). High anti­oxidant activities were recorded in the integument by the radical scavenging tests of ABTS and DPPH as well as by the total antioxidant capacity and the FRAP in comparison with the BHT standard. Our results showed that H. Tubulosa tegument has high nutritional value with high antioxidant activities and could be considered a nutraceutical product.El pepino de mar o la holoturia es una especie marina apreciada en algunos países asiáti­cos por sus cualidades nutricionales. El propósito de este trabajo fue estudiar la composición bioquímica y las actividades antioxidantes y de eliminación de radicales libres del tegumento de Holothuria tubulosa de la laguna de Bizerta, en el norte de Túnez. Los datos obtenidos demuestran que el extracto de tegumentos de pepino de mar mostró altos niveles bioquímicos (como humedad 80,77%, proteína 7,07%, lípidos 10,21%, valor energético 13,64 Kcal/gww) y un valor nutricional importante (incluyendo n-3/ n-6: 2,11, EPA+DHA: 20,96, AI: 1,38 y TI: 0,54). Se registraron altas actividades antioxidantes en el tegumento mediante las pruebas de eliminación de radicales de ABTS y DPPH, así como por la capacidad antioxidante total y el FRAP, y esto, en comparación con el estándar BHT. Nuestros resultados mostraron que el tegumento de H. Tubulosa tiene un valor nutricional importante con una alta actividad antioxidante y podría considerarse un producto nutracéutico

Seasonal variations of dioxine-like activity in sediments of the Bizerta lagoon (Tunisia) detected with in vitro cellular bioassays

In order to evaluate sediment contamination in six stations from Bizerta lagoon, a combination of in vitro bioassays and chemical analysis was applied to sediment organic extracts. By using 7- ethoxyresorufin-O-deethylase (EROD) induction in the fish hepatoma cell line PLHC-1 after 4 h of cell exposure, dioxin-like activities were detected in all analysed samples. Dioxin-like activities were higher in winter than in summer. A highly significant correlation was observed between bioassay- and chemical analyses-derived toxic equivalents (TEQs), but PAHs accounted for only a small part of the detected biological activities. Our results suggest the presence of unknown readily metabolised EROD inducing compounds, which will need to be further characterize

Monitoring of dioxin-like, estrogenic and anti-androgenic activities in sediments of the Bizerta lagoon (Tunisia) by means of in vitro cell-based bioassays: contribution of low concentrations of polynuclear aromatic hydrocarbons (PAHs).

International audienceWe used an array of in vitro cell-based bioassays to assess dioxin-like, estrogenic and (anti-)androgenic activities in organic extracts of sediments from the Bizerta lagoon, one of the largest Tunisian lagoons subjected to various anthropogenic and industrial pressures. The sediments were sampled both in winter and summer 2006 in 6 stations differently impacted and in one reference station located in the seawards entrance of Ghar el Melh lagoon. Chemical analyses of the 16 priority PAHs showed that the sediments were low to moderately contaminated (2-537 ng/g dry weight). By using the estrogen- (MELN) and androgen-responsive (MDA-kb2) reporter cell lines, significant estrogenic and anti-androgenic activities were detected only in the Menzel Bourguiba (MB) site, the most contaminated site, both in winter and summer. By using 7-ethoxyresorufin-O-deethylase (EROD) induction in the fish PLHC-1 cell line after both 4 and 24 h of cell exposure, dioxin-like activities were detected in all analysed samples. Dioxin-like activities were higher after 4 h exposure, and varied according to the sites and the sampling season. While highly significant correlation was observed between bioassay- and chemical analyses-derived toxic equivalents (TEQs), PAHs accounted for only a small part (up to 4%) of the detected biological activities, suggesting that other readily metabolised EROD-inducing compounds were present. This study argues for the use of short time exposure to assess biological TEQs in low contaminated samples and provides new induction equivalent factors (IEF(4h)) for 16 PAHs in the PLHC-1 cell line. Finally, our results stress the need to further characterise the nature of organic chemical contamination as well as its long-term impacts on aquatic wildlife in the Bizerta lagoon