Lymphatic absorption characteristics of eicosapentaenoic acid -enriched phosphoethanolamine plasmalogen and its gastric and intestinal hydrolysates

The aim of this work was to study the lymphatic absorption characteristics of gastric hydrolysates and intestinal hydrolysates of eicosapentaenoic acid-enriched phosphoethanolamine plasmalogen (EPA-pPE) with focusing on the fate of EPA and vinyl ether bonds in the lymph fluid using lymphatic intubation and lipidomics. The results showed that the EPA peak occurred earlier in the gastric (1.5 h) and intestinal (1 h) hydrolysates than in the EPA-pPE group (3 h) with EPA peak content being 2.03 and 1.46 times higher, suggesting pre-hydrolysis contributed to lymphatic absorption. Further, duodenal injection of gastric hydrolysates sn2 EPA-lysoPE produced higher levels of EPA-LPC, PC, PE, and PG. Meanwhile, intestinal hydrolysates free EPA and sn1 lyso-pPE enriched the sn1 + 2 + 3 TG (20:5_20:5_20:5) and increased the vinyl ether bond-containing lipids, such as PE (18:0p_18:0) and PE (18:0p_20:4). This study provides insight into dietary molecular structures of EPA and plasmalogen.