Résumé
Brown algae are well known as a source of biologically active compounds, especially those having antioxidant activities, such as phlorotannins. In this study we examined the antioxidant activities of crude phlorotannins extracts (CPEs) obtained from Sargassum hemiphyllum (SH) and fractionated according to the molecular weights. When CPEs were administrated at a dose of 30 mg/kg to Kunming mice pre-treated with carbon tetrachloride (CCl4), the levels of oxidative stress indicators in the liver, kidney and brain were significantly reduced in vivo. All the components of various molecular weight fractions of CPEs exhibited greater scavenging capacities in clearing hydroxyl free radical and superoxide anion than the positive controls gallic acid, vitamin C and vitamin E. Particularly, the components greater than 30 kD obtained from ethyl acetate phase showed the highest antioxidant capacities. These results indicated that SH is a potential source for extracting phlorotannins, the algal antioxidant compounds.
Sujets)
Animaux , Mâle , Souris , Antioxydants , Pharmacologie , Acide ascorbique , Pharmacologie , Encéphale , Métabolisme , Anatomopathologie , Tétrachloro-méthane , Toxicité , Intoxication au tétrachlorure de carbone , Traitement médicamenteux , Métabolisme , Anatomopathologie , Fractionnement chimique , Méthodes , Acide gallique , Pharmacologie , Radical hydroxyle , Métabolisme , Rein , Métabolisme , Anatomopathologie , Extraction liquide-liquide , Méthodes , Foie , Métabolisme , Anatomopathologie , Lignées consanguines de souris , Oxydoréduction , Stress oxydatif , Phaeophyceae , Chimie , Sargassum , Chimie , Superoxydes , Métabolisme , Tanins , Pharmacologie , Vitamine E , PharmacologieRésumé
The mice were administered with 10~40mg?kg~(-1)?d~(-1) SHP [Sargassum hemiphyllum(Turner) C.Agardh polysaccharides,SHP] ip for 7d before 5Gy ?-rays irradiation to observe the effect of SHP on the mRNA expression of CD~+_(34) and SCF(stem cell factor),and to study the mechanism of SHP against irradiation on the hematopoietic system in irradiated mice.Flow cytometry was used to detect number of bone marrow cells and the mRNA expression of CD~+_(34) and SCF were analysed by RT-PCR test.The results showed that the percentage of CD~+_(34) cells was decreased by ?-rays irradiation(5Gy) and SHP(10～40mg?kg~(-1)) could increase significantly the percentage of CD~+_(34) cells to exhibit a protective effect of SHP on bone marrow in irradiated mice.Expressions of CD~+_(34) and SCF mRNA were lower in model group than those in conrol group and the expressions were higher in three test groups than those in model group.The results indicated that the increases of expressions of CD~+_(34) and SCF mRNA could be a mechanism of SHP against irradiation on the hematopoietic system in mice.