Two pairs of diastereoisomeric isoflavone glucosides from the roots of Pueraria lobata.

Phytochemical investigation of the roots of Pueraria lobata led to the isolation of two pairs of new isoflavone glucosides, 3'-hydroxyneopuerarin A/B (1-2) and 3'-methoxyneopuerarin A/B (3-4). A pair of known compounds (5-6), which possess a very similar structure, were obtained together. Their structures were elucidated on the basis of spectroscopic data interpretation. Compounds 3-6 dose-dependently blocked the production of TNF-α and IL-6 in LPS-stimulated RAW264.7 cells, which indicated the potential anti-inflammatory effect of these compounds.

Polyphenolic compounds from Malus hupehensis and their free radical scavenging effects.

One new 4-chromanone glycoside, 5-O-ß-d-glucopyranoside-4-chromanone (1), together with 21 known polyphenols, was isolated from the leaves of Malus hupehensis. Their structures were elucidated on the basis of extensive spectroscopic methods including NMR (1D and 2D), mass (ESIMS and HRESIMS), IR, and by comparison with the data reported in the literature. Some of the isolated compounds were screened for antioxidant activity. Compounds 18 and 14 exhibited significant antioxidant activities with SC50 values 2.73 and 2.91 µg/mL, respectively, while 17, 19, 11, 7, 20, 22, 12 and 13 exhibited moderate activities with SC50 values ranging from 5.24-11.86 µg/mL. The HPLC fingerprint profiles of the leaves and fruits extracts were also analysed, which showed that the constituents were almost the same in both the extracts except for the content of phlorizin which was present in higher amount in the leaves.

Galactomannan with novel structure produced by the coral endophytic fungus Aspergillus ochraceus.

The homogeneous extracellular polysaccharide, AW1, was obtained from the fermented broth of the fungus Aspergillus ochraceus derived from coral Dichotella gemmacea. AW1 was a galactomannan with a molar ratio of mannose and galactose of 2.16:1.00 and a molecular weight of about 29.0kDa. The structure of AW1 was investigated by chemical and spectroscopic methods, including methylation analysis, one- and two-dimensional nuclear magnetic resonance (1D, 2D NMR) and electrospray mass spectrometry with collision-induced dissociation (ES-CID MS/MS) spectroscopic analyses. The results showed that the backbone of AW1 consisted of (1⟶2)-linked α-d-mannopyranose residues. The mannopyranose residues in the backbone were substituted at C-6 by the (1⟶)-linked α-d-mannopyranose units and (1⟶5)-linked ß-d-galactofuranose oligosaccharides with different degrees of polymerization. The investigation demonstrated that AW1 was a novel galactomannan with different structural characteristics from other fungal galactomannans, and could be a potential resource of the (1⟶5)-linked ß-d-galactofuranose oligosaccharides.

Structural elucidation of an extracellular polysaccharide produced by the marine fungus Aspergillus versicolor.

A homogenous extracellular polysaccharide, designated AWP, was isolated from the fermented liquid of the marine fungus Aspergillus versicolor from the coral Cladiella sp. and purified by anion-exchange and size-exclusion chromatography (SEC). Chemical and spectroscopic analyses, including one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopy showed that AWP consisted of glucose and mannose in a molar ratio of 8.6:1.0, and its average molecular weight was estimated to be 500kDa. AWP is a slightly branched extracellular polysaccharide. The backbone of AWP is mainly composed of (1→6)-linked α-D-glucopyranose residues, slightly branched by single α-d-mannopyranose units attached to the main chain at C-3 positions of the glucan backbone. The investigation demonstrated that AWP is a novel extracellular polysaccharide different from those of other marine microorganisms.

Preparation and characterization of an extracellular polysaccharide produced by the deep-sea fungus Penicillium griseofulvum.

The deep-sea fungus Penicillium griseofulvum produces an extracellular polysaccharide, Ps1-1, when grown in potato dextrose-agar medium. Ps1-1 was isolated from the fermented broth using ethanol precipitation, anion-exchange and size-exclusion chromatography. Ps1-1 is a galactomannan with a molecular weight of about 20 kDa, and a molar ratio of mannose and glucose of 1.1:1.0. On the basis of one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) and mass spectroscopic analyses, Ps1-1 is composed of a long chain of galactofuranan and a mannose core. The galactofuranan chain consists of (1→5)-linked ß-galactofuranose, with additional branches at C-6 consisting of (1→)-linked ß-galactofuranose residues and phosphate esters. The mannan core is composed of (1→6)-linked α-mannopyranose substituted at C-2 by (1→)-linked α-mannopyranose residues, disaccharide and trisaccharide units of (1→2)-linked α-mannopyranose. The investigation demonstrated that Ps1-1 was a galactofuranose-containing galactomannan differing from previously described extracellular polysaccharides.

Sequence analysis of the sulfated rhamno-oligosaccharides derived from a sulfated rhamnan.

Three sulfated rhamno-oligosaccharides, designated O1, O2 and O3, were obtained by mild acid hydrolysis of the sulfated rhamnan and purified by gel-permeation chromatography. On the basis of one- and two-dimensional nuclear magnetic resonance (1D, 2D NMR) spectroscopic analyses, the oligosaccharide O1 was characterized to be α-L-Rhap-(2SO4)-(1→3)-α-L-Rhap. The fragmentation pattern of the homogeneous disaccharide in the product ion spectra was recognized by negative-ion electrospray tandem mass spectrometry with collision-induced dissociation (ES-CID MS/MS). With the principles established, the sequences of the oligosaccharides O2 and O3 were deduced to be α-L-Rhap-(2SO4)-(1→3)-α-L-Rhap-(1→3)-α-L-Rhap, and α-L-Rhap-(2SO4)-(1→3)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-α-L-Rhap (2SO(4)), respectively. The investigation demonstrated that the sulfated rhamnan-derived oligosaccharides were novel sulfated oligosaccharides different from those of other polysaccharides-degraded from algae, and it could be possible to determine the sequence of the sulfated rhamno-oligosaccharides directly from the glycosidic cleavage fragmentation in the product ion spectra.

Chemical characteristic of an anticoagulant-active sulfated polysaccharide from Enteromorpha clathrata.

A sulfated polysaccharide FEP from marine green alga Enteromorpha clathrata was extracted with hot water and further purified by ion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that FEP was a high arabinose-containing sulfated polysaccharide with sulfate ester of 31.0%, and its average molecular weight was about 511kDa. The backbone of FEP was mainly composed of (1→4)-linked ß-L-arabinopyranose residues with partially sulfate groups at the C-3 position. In vitro anticoagulant assay indicated that FEP effectively prolonged the activated partial thromboplastin time and thrombin time. The investigation demonstrated that FEP was a novel sulfated polysaccharide with different chemical characteristics from other sulfated polysaccharides from marine algae, and could be a potential source of anticoagulant.