RESUMEN
Two pectins from the seagrass Enhalus acoroides (L.f.) Royle were isolated for the first time. Their structures and biological activities were investigated. NMR spectroscopy showed one of them to consist exclusively from the repeating â4-α-d-GalpUAâ residue (Ea1), while the other had a much more complex structure that also included 1â3-linked α-d-GalpUA residues, 1â4-linked ß-apiose residues and small amounts of galactose and rhamnose (Ea2). The pectin Ea1 showed noticeable dose-dependent immunostimulatory activity, the Ea2 fraction was less effective. Both pectins were used to create pectin-chitosan nanoparticles for the first time, and the influence of pectin/chitosan mass ratio on their size and zeta potential was investigated. Ea1 particles were slightly smaller than Ea2 particles (77 ± 16 nm vs 101 ± 12 nm) and less negatively charged (-23 mV vs -39 mV). Assessment of their thermodynamic parameters showed that only the second pectin could form nanoparticles at room temperature.
Asunto(s)
Quitosano , Nanopartículas , Pectinas/química , Poaceae , Quitosano/farmacología , Quitosano/química , Nanopartículas/química , RamnosaRESUMEN
Fucosylated chondroitin sulfates (FCSs) FCS-BA and FCS-HS, as well as fucan sulfates (FSs) FS-BA-AT and FS-HS-AT were isolated from the sea cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera, respectively. Purification of the polysaccharides was carried out by anion-exchange chromatography on DEAE-Sephacel column. Structural characterization of polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of non-destructive NMR spectroscopic methods. Both FCSs were shown to contain a chondroitin core [â3)-ß-d-GalNAc-(1â4)-ß-d-GlcA-(1â]n bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in pattern of sulfation: FCS-BA contained Fuc2S4S, Fuc3S4S and Fuc4S at a ratio of 1:8:2, while FCS-HS contained these residues at a ratio of 2:2:1. Polysaccharides differed also in content of GalNAc4S6S and GalNAc4S units, the ratios being 14:1 for FCS-BA and 4:1 for FCS-HS. Both FCSs demonstrated significant anticoagulant activity in clotting time assay and potentiated inhibition of thrombin, but not of factor Xa. FS-BA-AT was shown to be a regular linear polymer of 4-linked α-L-fucopyranose 3-sulfate, the structure being confirmed by NMR spectra of desulfated polysaccharide. In spite of considerable sulfate content, FS-BA-AT was practically devoid of anticoagulant activity. FS-HS-AT cannot be purified completely from contamination of some FCS. Its structure was tentatively represented as a mixture of chains identical with FS-BA-AT and other chains built up of randomly sulfated alternating 4- and 3-linked α-L-fucopyranose residues.
Asunto(s)
Holothuria , Pepinos de Mar , Animales , Anticoagulantes/química , Anticoagulantes/farmacología , Sulfatos de Condroitina/química , Fucosa/química , Holothuria/química , Polisacáridos/farmacología , Pepinos de Mar/química , Sulfatos/farmacologíaRESUMEN
The aim of this study was to establish the fine structure of fucoidan from Sargassum oligocystum and to study the radiosensitizing effect of fucoidans from three algae of genus Sargassum (S. oligocystum, S. duplicatum, and S. feldmannii) with different structures. The fucoidan SoF2 from S. oligocystum was sulfated (32%) galactofucan (Fuc:Gal = 2:1), with a Mw of 183 kDa (Mw/Mn = 2.0). Its supposed structure was found to be predominantly 1,3-linked fucose as the main chain, with branching points at C2 and C4. The branches could be single galactose and/or fucose short chains with terminal galactose residues. Sulfate groups were found at positions C3, C2, and/or C4 of fucose residues and at C2 and/or C4 of galactose residues. The radiosensitizing effect of galactofucans from S. oligocystum, S. duplicatum, and S. feldmannii against human melanoma SK-MEL-28, colon HT-29, and breast MDA-MB-231 cancer cells was investigated. The influence of all investigated polysaccharides treatments with/without X-ray radiation on colony formation of human melanoma cells SK-MEL-28 was weak. Fucoidan from S. feldmannii has been shown to be the most promising radiosensitizing compound against human colon HT-29 and breast MDA-MB-231 cancer cells.
Asunto(s)
Polisacáridos/química , Sargassum/química , Línea Celular Tumoral , Células HT29 , Humanos , Fármacos Sensibilizantes a Radiaciones/químicaRESUMEN
Extraction process of Cucumaria frondosa japonica Semper, 1868, which are subspecies of Cucumaria frondosa (Gunnerus, 1767), were studied. It was shown that supercritical carbon dioxide extraction of holothuria was more effective than conventional solvent extraction. Step-by-step extraction with carbon dioxide followed by supercritical extraction with the addition of a co-solvent of ethanol can almost double the yields of extracts of triterpene glycosides, styrenes and carotenoids. Moreover, the fraction of triterpene glycosides practically does not contain colored impurities, in contrast to traditional ethanol extraction. The obtained extracts by HPLC in combination with tandem mass spectrometry (HPLC-MS/MS) identified 15 triterpene glycosides, 18 styrene compounds and 14 carotenoids. Supercritical extraction made it possible to obtain extracts with yields superior to conventional hexane and alcohol extracts. Moreover, such an approach with the use of supercritical fluid extraction (SFE) and subsequent profiling of metabolites can help with the study of holothuria species that are not as well studied.