Structural variation of lignin-carbohydrate complexes (LCC) in Chinese quince (Chaenomeles sinensis) fruit as it ripens.

Chinese quince (Chaenomeles sinensis) fruits are rich in lignin, and too sour, astringent and woody to be eaten raw. More than 50 % of lignin in plant cell walls is covalently associated with carbohydrates to form lignin-carbohydrate complexes (LCC). In this study, LCC preparations were extracted from fruits harvested on the 15th day of the month from May-October 2019. A variety of chemical and instrumental analytical approaches were used to characterize the LCC fractions, including HPAEC, TGA, GPC, FT-IR, and 2D HSQC NMR. Antioxidant activities were evaluated by DPPH radical scavenging assays. Results showed that the LCC fractions from October fruits had better thermal stability and homogeneity. NMR results revealed that the lignin-lignin linkages in LCC-AcOH preparations included ß-O-4', ß-ß' and ß-5', but ß-5' linkages were not present in LCC preparations. And the NMR signals of carbohydrate confirmed the presence of lignin-pectin complexes, which was consistent with sugar analysis. All LCC preparations showed good antioxidant activity, among which Björkman LCC from October fruits showed best. This study will facilitate understanding the chemical bonds of LCC macromolecules in the plant cell wall. More specifically, it provides information critical for specific industrial applications of quince fruits.

Corrigendum: Characterization of structure and antioxidant activity of polysaccharides from sesame seed hull.

[This corrects the article DOI: 10.3389/fnut.2022.928972.].

Characterization of Structure and Antioxidant Activity of Polysaccharides From Sesame Seed Hull.

Sesame seed hull is the major by-product of sesame seed processing and is rich in polysaccharides. In this work, sesame hull polysaccharides (SHP) were extracted by ultrasound-assisted alkali extraction methods with a yield of 6.49%. Three purified polysaccharide fractions were obtained after decolorization, deproteinization, and column chromatography. Then, their main composition and antioxidant activity were investigated. The dominant fraction was SHP-2 with a yield of 3.78%. It was composed of galacturonic acid (51.3%), glucuronic acid (13.8%), rhamnose (8.9%), glucose (8.4%), and others. The linkage types of SHP-2 have the α-D-GalpA-(1,4)-linked, α-D-GlcpA-(1,2)-linked, ß-T-D-Rhap-linked, ß-D-Glcp-(1,6)-linked, ß-T-D-Galp-linked, α-L-Xylp-(1,4)-linked, α-L-Araf-(1,3,5)-linked, and ß-D-Manp-(1,4)-linked. This study might provide some useful basic data for developing applications for sesame seed hull polysaccharides in the food and pharmaceutical industries.

Clinical Comparison of Selective versus Nonselective Decompression for Symptomatic Tandem Stenosis of the Cervical and Thoracic Spine: A Retrospective Cohort Study.

OBJECTIVE: The aim of the present paper was to reveal the clinical differences between selective and nonselective decompression for symptomatic tandem stenosis of the cervical and thoracic spine (TSCTS). METHODS: A total of 34 patients were eligible and included in the study. Among them, 8 patients underwent selective cervical decompression (CD), 15 patients underwent selective thoracic decompression (TD), and 11 patients underwent combined CD and TD (CTD) surgery. Age, sex, operative time, intraoperative blood loss, postoperative hospital stay, inpatient expenditure, preoperative upper Japanese Orthopaedic Association (JOA) rate, canal occupation rate, high-intensity T2-weighted image (T2WI) of the spinal cord, and preoperative and postoperative JOA scores were compared among the three groups. RESULTS: The CD group had shorter operative time (138.8 ± 36.1 vs 229.7 ± 95.8 vs 328.6 ± 94.8, min, P < 0.001), less intraoperative blood loss (141.3 ± 116.7 vs 496.7 ± 361.8 vs 654.6 ± 320.5, mL, P = 0.004), and shorter postoperative hospital stay (4.6 ± 1.6 vs 9.0 ± 3.5 vs 10.3 ± 6.6, days, P = 0.008), as well as lower preoperative upper JOA rate (34.1 ± 5.6 vs 53.9 ± 8.4 vs 48.2 ± 15.2, %, P = 0.001) than the TD and CTD groups. The CTD group had higher inpatient expenditure than the CD and TD groups (87,850 ± 18,379 vs 55,100 ± 12,890 vs 55,772 ± 15,715, CNY, P < 0.001). The cervical canal occupation rates were similar among different groups (P > 0.05); however, the TD group showed a higher thoracic canal occupation rate than the CD group (58.3 ± 14.7 vs 43.3 ± 12.3, %, P = 0.035). All positive levels in high-intensity T2WI of the spinal cord were decompressed. The preoperative JOA scores as well as the postoperative JOA scores at 6 months and at last follow-up were comparable among the three groups (P > 0.05). Similarly, the JOA recovery rate showed no significant difference among the groups (P > 0.05). CONCLUSION: Selective CD or TD alone demonstrated similar clinical effectiveness to nonselective and combined CTD for TSCTS. Individualized surgical decision should be made after meticulous assessments of clinical and radiological manifestations, general patient condition, and socioeconomic factors.

Structural Changes in Milled Wood Lignin (MWL) of Chinese Quince (Chaenomeles sinensis) Fruit Subjected to Subcritical Water Treatment.

Subcritical water treatment has received considerable attention due to its cost effectiveness and environmentally friendly properties. In this investigation, Chinese quince fruits were submitted to subcritical water treatment (130, 150, and 170 °C), and the influence of treatments on the structure of milled wood lignin (MWL) was evaluated. Structural properties of these lignin samples (UL, L130, L150, and L170) were investigated by high-performance anion exchange chromatography (HPAEC), FT-IR, gel permeation chromatography (GPC), TGA, pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 2D-Heteronculear Single Quantum Coherence (HSQC) -NMR, and 31P-NMR. The carbohydrate analysis showed that xylose in the samples increased significantly with higher temperature, and according to molecular weight and thermal analysis, the MWLs of the pretreated residues have higher thermal stability with increased molecular weight. The spectra of 2D-NMR and 31P-NMR demonstrated that the chemical linkages in the MWLs were mainly ß-O-4' ether bonds, ß-5' and ß-ß', and the units were principally G- S- H- type with small amounts of ferulic acids; these results are consistent with the results of Py-GC/MS analysis. It is believed that understanding the structural changes in MWL caused by subcritical water treatment will contribute to understanding the mechanism of subcritical water extraction, which in turn will provide a theoretical basis for developing the technology of subcritical water extraction.