ABSTRACT
Matrix-assisted ultraviolet laser-desorption ionization time-of-flight mass spectrometry (UV-MALDI-TOF-MS) was applied to sulfated xylo-mannan fractions from Nothogenia fastigiata in order to determine their molecular weights and distribution profiles. The number-average molecular weight calculated from the spectra was similar to that determined by chemical end-group analysis for the lower molecular weight fractions. For the other fractions, the number-average molecular weight was lower than that chemically determined; the increased difference may be attributed to higher desorption difficulties and, consequently, mass-dependent discrimination. A reconstructed spectrum, using the peaks obtained from all the fractions, suggested an unimodal distribution. The best results were obtained by using 2,5-dihydroxybenzoic acid as matrix doped with 1-hydroxyisoquinoline and with harmane and nor-harmane.
Subject(s)
Gentisates , Mannans/chemistry , Seaweed/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Hydroxybenzoates/pharmacology , Mannans/analysis , Molecular Weight , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/standards , Sulfates/chemistry , Ultraviolet Rays , Xylose/chemistryABSTRACT
Structural analysis of two xylomannans extracted from Nothogenia fastigiata was carried out. The results are consistent with the general pattern previously reported for other xylo-mannans of the same system, alpha-(1-->3)-linked D-mannans 2- and 6-sulfated and having single stubs of beta-(1-->2)-linked D-xylose, but one of the new samples contains a significant amount of 2,6-disulfated units. Both xylomannans studied are obtained as complexes with a beta-D-(1-->3)-, alpha-L-(1-->4)-galactan and a beta-D-(1-->3)-, beta-D-(1-->4)-'mixed linkage' xylan co-existing in the seaweed, a fact that limits the accuracy of the data determined. The structures of the galactan and the xylan are similar to those previously informed for this seaweed. The antiviral activity against four different herpes simplex viral strains and the anticoagulant properties of all the xylo-mannans of the system are reported.
Subject(s)
Anticoagulants/chemistry , Antiviral Agents/chemistry , Mannans/chemistry , Mannans/pharmacology , Simplexvirus/drug effects , Anticoagulants/pharmacology , Antiviral Agents/pharmacology , Carbohydrate Conformation , Galactans/chemistry , Galactans/isolation & purification , Galactose/analysis , Magnetic Resonance Spectroscopy , Mannans/analysis , Mannans/isolation & purification , Mannose/analysis , Molecular Weight , Seaweed/chemistry , Sulfates/analysis , Xylans/chemistry , Xylans/isolation & purification , Xylose/analysis , Xylose/chemistryABSTRACT
The structures of two alpha-(1-->3)-alpha-D-xylo-mannans were determined. The different antiviral activity of the xylo-mannans from Nothogenia fastigiata was explained on the basis of a flexible backbone, molecular size, content and distribution of sulfate groups and of the single stubs of beta-(1-->2)-linked D-xylose.
