Structural characterization of a polysaccharide from Portulaca oleracea L. and its promotion of skin wound healing via regulating Notch pathway

Skin wounds occur frequently in everyday life, and severe wounds can be life-threatening. Portulaca oleracea L. is a medicinal plant widely used in moisturisers and other skincare products, and polysaccharides are considered its principal active constituents. However, research on the wound-healing effects of P. oleracea polysaccharides and their underlying molecular mechanisms remains limited. In this study, a novel polysaccharide designated WPOP-1-1 was isolated from P. oleracea L., and characterised. The weight-average molecular weight (Mw) of WPOP-1-1 was 7.4 kDa. The backbone of WPOP-1-1 is mainly composed of 1,4-linked glucopyranose (Glcp) and 1,4-linked galactopyranose (Galp) repeating units, with 1,5-linked arabinofuranose (Araf) or terminal glucopyranose (t-Glcp) branches attached at O-6 of the glucopyranose units. Combined in vitro and in vivo assays verified that WPOP-1-1 boosted keratinocyte and fibroblast migration, accelerated mouse wound closure, restored epidermal barrier and alleviated inflammatory infiltration. Proteomic enrichment, immunofluorescence, and western blot results collectively suggested that WPOP-1-1 may upregulate proteins of the Notch pathway. Collectively, these findings indicate that WPOP‑1‑1 may contribute to wound healing by modulating Notch signaling, providing preliminary evidence for its potential use in wound repair and skincare products.