Chemical structure elucidation of total lignins in woods. Part II: Analysis of a fraction of residual wood left after MWL isolation and solubilized in lithium chloride/N,N-dimethylacetamide

Holzforschung ◽  
2006 ◽  
Vol 60 (6) ◽  
pp. 653-658 ◽  
Author(s):  
Hiroyuki Furuno ◽  
Toshiyuki Takano ◽  
Shuichi Hirosawa ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Lithium Chloride ◽  
Structure Elucidation ◽  
Chemical Structure ◽  
Soluble Fraction ◽  
Elution Curve ◽  
Mass Region ◽  
Milled Wood Lignin ◽  
Cellulose Solvent ◽  
Lignin Fraction ◽  
Partial Degradation

Abstract The residual wood meal left after extraction of milled wood lignin (MWL) was extracted with lithium chloride/N,N-dimethylacetamide, which is a well-known cellulose solvent, to afford a soluble fraction (cellulose-lignin fraction; CL) in 36.7% yield. The UV elution curve of CL acetate has the same profile as its refractive index (RI) elution curve. After partial degradation of CL by cellulase, the UV elution curve of CL acetate shifted to the low-molecular-mass region in a similar fashion as its RI elution curve. These results indicate that the lignin in CL (CL lignin) is chemically bonded to cellulose. On the other hand, half of the CL lignin was removed by xylanase treatment. It was concluded that approximately half of the CL lignin existed as a lignin-cellulose-xylan complex.

Fractionation and characterization of lignin carbohydrate complexes (LCCs) of Eucalyptus globulus in residues left after MWL isolation. Part I: Analyses of hemicellulose-lignin fraction (HC-L)

Holzforschung ◽  
2012 ◽  
Vol 66 (4) ◽  
Author(s):  
Yasuyuki Miyagawa ◽  
Ooki Takemoto ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Acetic Anhydride ◽  
Lithium Chloride ◽  
Eucalyptus Globulus ◽  
Soluble Fraction ◽  
Insoluble Fraction ◽  
Milled Wood Lignin ◽  
Cellulose Solvent ◽  
Lignin Fraction ◽  
Subsequent Deacetylation

Abstract The residual wood meal left after milled wood lignin (MWL) isolation (MWR) was extracted with the cellulose solvent lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) to obtain a soluble fraction (C-L) and an insoluble fraction (C-L-residue). The C-L-residue was further extracted with the hemicellulose solvent 3 M NaOH to give a soluble fraction named hemicellulose-lignin fraction (HC-L) with 21.3% yield based on MWR. It was found that HC-L was composed of xylan, cellulose and lignin with abundant S-type β-O-4 substructures. HC-L lignin was bonded to HC-L cellulose or HC-L hemicelluloses or both. The method, which comprised acetylation for hardwood xylan (by acetic anhydride/pyridine/formamide) and extraction with chloroform, was found to be effective for selective xylan acetate fractionation. HC-L was further fractionated by the same method and subsequent deacetylation to give a xylan-lignin fraction (X-L) in 11.3% yield based on HC-L. X-L was composed mainly of xylan and lignin with abundant S-type β-O-4 substructures, and bonded to X-L xylan. X-L is considered as a promising fraction for elucidation of the structure of lignin-carbohydrate linkages.

scholarly journals Ubiquitin-Proteasome Modulating Dolabellanes and Secosteroids from Soft Coral Clavularia flava

Marine Drugs ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 39
Author(s):  
Che-Yen Chiu ◽  
Xue-Hua Ling ◽  
Shang-Kwei Wang ◽  
Chang-Yih Duh
Keyword(s):  
Inhibitory Activity ◽  
Structure Elucidation ◽  
Chemical Structure ◽  
Soft Coral ◽  
Proteasome Inhibitors ◽  
Proteasome Inhibition ◽  
Structural Elucidation ◽  
Bioactive Molecules ◽  
High Content Screening ◽  
Ubiquitin Proteasome

We performed a high-content screening (HCS) assay aiming to discover bioactive molecules with proteasome inhibitory activity. By structural elucidation, we identified six compounds purified from soft coral Clavularia flava, which potentiates proteasome inhibition. Chemical structure elucidation revealed they are dolabellane- and secosteroid-based compounds including a new dolabellane, clavinflol C (1), three known dolabellanes, stolonidiol (2), stolonidiol-17-acetate (3), and clavinflol B (4) as well as two new secosteroids, 3β,11-dihydroxy-24-methyl-9,11-secocholest-5-en-9,23-dione (5) and 3β,11-dihydroxy-24-methylene-9,11-secocholest-5-en-9,23-dione (6). All six compounds show less cytotoxicity than those of known proteasome inhibitors, bortezomib and MG132. In summary, the high-content measurements of control inhibitors, bortezomib and MG132, manifest the highest ratio >2 in high-content measurement. Of the isolated compounds, 2 and 5 showed higher activity, followed by 3 and 6, and then 1 and 4 exhibited moderate inhibition.

Hydrolytic processes and condensation reactions in the cellulose solvent system N,N-dimethylacetamide/lithium chloride. Part 2: degradation of cellulose

Polymer ◽  
2003 ◽  
Vol 44 (1) ◽  
pp. 7-17 ◽  
Author(s):  
Antje Potthast ◽  
Thomas Rosenau ◽  
Jürgen Sartori ◽  
Herbert Sixta ◽  
Paul Kosma
Keyword(s):  
Lithium Chloride ◽  
Solvent System ◽  
Cellulose Solvent ◽  
Condensation Reactions
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