Isolation, purification, degradation of citrus pectin and correlation between molecular weight and their biological properties

• Published in: Food science & technology Vol. 196; p. 115837
• Main Authors: Guo, Huan, Du, Yongjun, Gao, Haichuan, Liao, Ying, Liu, Hongyan, Wu, Dingtao, Gan, Renyou, Gao, Hong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.03.2024
• Subjects: Anticancer; Citrus pectin; Immunostimulatory activity; Structure-function relationship; Anticancer; Structure-function relationship; Citrus pectin; Immunostimulatory activity
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2024.115837

Citrus pectin (CP) and two pectins with distinct molecular weights (CP-1 and CP-2) were prepared using ultrasound-assisted H2O2/ascorbic acid reaction, and their structural, anticancer, and immunostimulatory properties were investigated. Based on the methylation and nuclear magnetic resonance analyses, the structure of CP-2 was determined to be composed of an α-1,4-linked homogalacturonan backbone that exhibited high levels of O-6 methylation. In addition, both CP-1 and CP-2 induced apoptosis in various cancer cell lines, while CP exhibited minimal impact. All tested CPs activated RAW264.7 cells, promoting the production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 by upregulating the expression of TNF-α, IL-6, and inducible NO synthase genes. Among them, CP-2 exhibited the highest immunostimulatory activity closely linked with its molecular weight. Furthermore, we found that CP-2 could activate RAW264.7 macrophages through NOD-like receptor (NLR) signaling pathways involving nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. In summary, the results of this investigation will enhance the comprehension of the structure-function correlation of CP, furthering its application within the functional food industry. •Citrus pectin (CP) and two molecular-weight pectins (CP-1 and CP-2) were prepared.•The structural and biological properties of the CPs were systematically examined.•The immunoregulatory mechanism of CP-2 was elucidated via proteomics analysis.•The findings contribute to revealing the structure-activity relationship of CPs.