Evaluation of intestinal absorption of deoxyribonucleic acid components in salmon milt extract using <i>in-situ</i> and <i>in-vitro</i> gastrointestinal absorption models

Salmon milt extract (SME) is rich in deoxyribonucleic acids and has been suggested as a functional material. However, whether these components contribute to SME's functionality remains unclear, and data on their intestinal absorption are limited. This study investigated absorption mechanisms of deoxyribonucleic acid components in SME using in-situ and in-vitro models. Ultra-performance liquid chromatography/tandem mass spectrometry was used to simultaneously quantify four deoxyribonucleosides (dNs). The in-situ rat intestinal loop study showed increased levels of 2'-deoxyadenosine (dAdo) and 2'-deoxyguanosine (dGuo) in the portal vein. In the transcellular transport assay, dAdo and dGuo levels on the receiver side increased in a time-dependent manner after SME treatment, particularly in human induced pluripotent stem cell-derived small intestinal epithelial cells. No increase in 2'-deoxycytidine or thymidine levels was observed under any experimental condition. These results indicate that purine dNs are absorbed into the portal vein after oral intake of SME, whereas intestinal absorption of pyrimidine dNs is limited.