Pectin oligosaccharides from Citri Reticulatae Pericarpium ‘Chachi’ promote wound healing in HaCaT keratinocytes by enhancing cell proliferation and migration

•Pectin oligosaccharides were extracted from Citri Reticulatae Pericarpium ‘Chachi’ in a green and environmentally friendly way.•Predominant oligosaccharide (CPOS3) in Citri Reticulatae Pericarpium ‘Chachi’ was characterized.•The thermal stability and rheological property of CPOS3 were evaluated.•CPOS3 promote the proliferation and migration of HaCaT cell. Citri Reticulatae Pericarpium ‘Chachi’ (Citrus reticulata ‘Chachi’) is a traditional Chinese medicine with dual medicinal and dietary uses. As its main component, pectin exhibited various biological activities. However, research and development on it, especially pectin oligosaccharides, remain limited. In this study, ‘Chachi’ pectin oligosaccharides (CPOS) was extracted and prepared for the first time, resulting in the purification of two oligosaccharide components, CPOS3 and CPOS4. Structural characterization of the predominant oligosaccharide, CPOS3, revealed it to be composed of a backbone α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-α-D-3-OAc-GalpA-(1→4)-α-D-GalpA-(1→4)-α-D-GalpA and a side chain [→5)-α-L-Araf-(1→]4 attached at the C-4 of Rhap. Subsequent experiments have shown that CPOS3 can significantly promote the proliferation and migration of human immortalized keratinocyte cell. Further investigation revealed that it facilitated cell proliferation by stimulating DNA synthesis in the S phase of the cell cycle. Additionally, CPOS3 exhibited good thermal stability and rheological characteristics. Based on the good wound healing activity and favorable physicochemical properties of CPOS3, its prospects in the fields of wound dressings and tissue repair are promising. [Display omitted]