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1 H NMR spectra of netural cyclosophoraoses of Sinorhizobium trifolii TA-1 (a) and succinylated cyclosophoraoses by chemical modification (c). Positive ion MALDI TOF mass spectrum of succinylated cyclosophoraoses by chemical modification (b) and enlarged spectrum of m/z 6,000-12,000 (d).
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Cyclosophoraoses (Cys) are unique molecules that are produced by all members of the family Rhizobiaceae. They were originally found not only in the periplasmic space but also in the extracellular media of Agrobacterium and Sinorhizobium species as fast-growing soil bacteria. 1 In Agrobacterium and Sinorhizobium species, they are a family of unbranc...
Citations
... The average sulfate contents were 2.25 per glucose. Succinylation was carried out using succinic anhydride and 4-(dimethylamino)pyridine, and the succinate groups were attached at the C3, C4, and C6 position [99,100]. As cationic derivatives, amine functionalization was prepared by tosylation, azidation, and amination of cyclic b-(1,2) glucans [101]. ...
Cyclic β-glucans are unique constituents that are found in the periplasmic space and extracellular media of Agrobacterium, Rhizobium, Bradyrhizobium, Rhodobacter, Xanthomonas, and Ralstonia species. Based on their glycosidic linkages, they are classified into three groups composed of cyclic β-(1,2), β-(1,3)-β-(1,6), and β-(1,2)-α-(1,6) linked glucans. Their degrees of polymerization vary ranging from 10 to 40 glucose residues, and the backbone structure can be modified with non-sugar moieties. Since the macrocyclic oligosaccharides possess their own characteristics such as inherent three-dimensional structures, hydrogen bonding, and complex-forming abilities, various possible applications would be of interest in the field of green chemistry, separation science, pharmaceutical, and food industries. In this review, we have addressed the properties and current applications of bio-sourced cyclic β-glucans and their derivatives.
... In addition, Cys have been combined with ergosterol, paclitaxel, naproxen, and luteolin to form inclusion complexes [10][11][12][13][14]. In a recent report, to expand the potential application of Cys, the hydroxyl group of Cys has been modified to various functional groups, including carboxymethyl, sulfonyl, succinyl, and butyryl groups [15][16][17][18][19][20][21]. In particular, butyryl Cys possessed a degree of substitution (DS) of 10, and thus, isoflavones/ butyryl Cys complex was formed due to the hydrophobicity of the butyryl group [21]. ...
Methylated cyclosophoraoses (M-Cys) were synthesized by reaction using dimethyl sulfate with native Cys (unbranched cyclic β-1,2-d-glucans) isolated from Rhizobium leguminosarum biovar viciae VF-39. Its structure was proven using nuclear magnetic resonance (1H NMR) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Based on the enhanced hydrophobicity by methylation of Cys, we investigated the inclusion property with the water-insoluble flavonoid, galangin, through a phase solubility study using ultraviolet–visible spectroscopy. The solubility of galangin was enhanced 5.6-fold according to the added concentrations (1 mM) of M-Cys, compared to the 1.9-fold and 3.4-fold enhancements by β-Cyclodextrin (β-CD) and heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD), respectively. M-Cys was also shown to have the highest binding constant (5,534 M−1) with galangin among the tested host molecules (β-CD, DM-β-CD, Cys, and M-Cys). From this result, we can infer that the complex of galangin with M-Cys is more stable than any of the other host molecules. The continuous variation method showed that the galangin/M-Cys complex was suitable for 1:1 stoichiometry. The formation of the complex was confirmed with 1H NMR, FT-IR, differential scanning calorimetry, and scanning electron microscopy. Furthermore, the hypothetical molecular model of 1:1 galangin/M-Cys complex was suggested by molecular docking simulations. The cytotoxicity to the human cervical adenocarcinoma cell lines was enhanced by the galangin/M-Cys complex compared with free galangin. The obtained results indicate that M-Cys can be utilized as an effective complexing agent for galangin.
... Previous studies have shown that Cys possesses the ability to form complexes with hydrophobic guest molecules including fluorescein, indomethacin, naproxen, paclitaxel, and vitamins (Koizumi et al., 1984;Kwon et al., 2012;Okada, Horiyama, & Koizumi, 1986). Furthermore, the applications of Cys in biotechnology can be broadened by modifying various substituents such as carboxymethyl (Lee, Park, Seo, Choi, & Jung, 2004), sulfonyl (Park, Lee, Kang, Jung, & Jung, 2004), and succinyl groups (Kwon and Jung, 2011). ...
Cyclosophoraoses [cyclic β-(1,2)-glucan, Cys] isolated from Rhizobium leguminosarum biovar trifolii TA-1 have unique structures and high solubility, which make it a potent solubilizer for host–guest inclusion complexation. Succinylated cyclosophorasoses (S-Cys) were also synthesized by chemically modifying isolated cyclosophoraoses. In ultraviolet-visible studies using naproxen (NAP), Cys was shown to form the most stable complexes with NAP (K
1:1 = 2457.9 M−1), which was followed by the negatively charged S-Cys (K
1:1 = 357.1 M−1) at pH 3.4. A further strong reduction in the complex stability constant was observed at pH 7.5. When the reduction in the stability constant was compared with other cyclic oligosaccharides (Cys; 119.2 M−1, CD; 14.48 M−1 and HP-CD; 6.75 M−1), S-Cys (K
1:1 = 5.6 M−1) was shown to have the highest decrease in stability constant. These results suggest that the S-Cys could regulate the efficiency of inclusion complexation at external pH values. NMR studies of complex formation between NAP and Cys also showed a different correlation pattern at pH 3.4 and 7.5. This difference in correlation demonstrates that the inclusion complexes between Cys and NAP formed as a result of the differential charge distribution of the carboxyl groups of NAP. The pH-dependent inclusion behavior of Cys for NAP was also evaluated using molecular docking simulations.
