Separation of saccharides using fullerene-bonded silica monolithic columns via π interactions in liquid chromatography.

We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH-π and/or OH-π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC-mass spectrometry with non-labeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide-fullerene was formed through CH-π and/or OH-π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipole-induced dipole interaction was dominant, and that maltose-with the higher dipole moment-was more strongly retained compared to other disaccharides having lower dipole moment.

Phenylpropanoid profiling reveals a class of hydroxycinnamoyl glucaric acid conjugates in Isatis tinctoria leaves.

The brassicaceous herb, Isatis tinctoria, is an ancient medicinal plant whose rosette leaf extracts have anti-inflammatory and anti-allergic activity. Brassicaceae are known to accumulate a variety of phenylpropanoids in their rosette leaves acting as antioxidants and a UV-B shield, and these compounds often have pharmacological potential. Nevertheless, knowledge about the phenylpropanoid content of I. tinctoria leaves remains limited to the characterization of a number of flavonoids. In this research, we profiled the methanol extracts of I. tinctoria fresh leaf extracts by liquid chromatography - mass spectrometry (LC-MS) and focused on the phenylpropanoid derivatives. We report the structural characterization of 99 compounds including 18 flavonoids, 21 mono- or oligolignols, 2 benzenoids, and a wide spectrum of 58 hydroxycinnamic acid esters. Besides the sinapate esters of malate, glucose and gentiobiose, which are typical of brassicaceous plants, these conjugates comprised a large variety of glucaric acid esters that have not previously been reported in plants. Feeding with 13C6-glucaric acid showed that glucaric acid is an acyl acceptor of an as yet unknown acyltransferase activity in I. tinctoria rosette leaves. The large amount of hydroxycinnamic acid derivatives changes radically our view of the woad metabolite profile and potentially contributes to the pharmacological activity of I. tinctoria leaf extracts.

Glucaric acids from Leonurus japonicus.

Three new glucaric acids, namely 2-feruloyl-4-syringoyl or 5-feruloyl-3-syringoyl glucaric acid (1), 2-syringoyl-4-feruloyl or 5-syringoyl-3-feruloyl glucaric acid (2), and 3-feruloyl-4-syringoyl or 4-feruloyl-3-syringoyl glucaric acid (3), were isolated from Leonurus japonicus Houtt. Their structures were elucidated by detailed spectroscopic means including UV, IR, HR-ESI-MS, 1D and 2D NMR data spectra. The bioactive assays of compounds 1-3 against hepatoprotection activity were determined. The result suggested that compound 2 exhibited a moderate hepatoprotection activity and the cell survival rate was 74% (10(-5)mol/L), using bicyclol (survival rate: 66%, 10(-5)mol/L) as a positive control. Furthermore, compounds 1-3 were evaluated cytotoxic activities in vitro using HCT-8, Bel-7402, BGC-823, A-549, and A2780 model and the results exhibited no obvious cytotoxicity activity.

The first fluorescent sensor for D-glucarate based on the cooperative action of boronic acid and guanidinium groups.

A new fluorescent sensor (1) with a recognition unit consisting of a boronic acid moiety and a guanidinium unit shows selective binding of D-glucarate in aqueous solution.