Antioxidant capacity of 12 major soybean isoflavones and their bioavailability under simulated digestion and in human intestinal Caco-2 cells

• Published in: Food chemistry 2022-04, Vol.374, p.131493, Article 131493
• Main Authors: Kim, Mi-Seon, Jung, Young Sung, Jang, Davin, Cho, Chi Heung, Lee, Sang-Hoon, Han, Nam Soo, Kim, Dae-Ok
• Format: Article
• Language: English
• Subjects: Antioxidants; Bioaccessibility; Biological Availability; Caco-2 Cells; Cellular accumulation; Digestion; Digestion stability; Glycine max; Humans; Isoflavone conjugate; Isoflavones; Permeability; Transwell system
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2021.131493

[Display omitted] •Acetyl conjugate of isoflavones in the intestinal digestion had the lowest stability.•Isoflavone aglycones had the highest permeability and cellular accumulation.•Glycitein had the lowest permeability and cellular accumulation among 12 isoflavones.•Caco-2 cells can use acetyl and malonyl conjugates of isoflavones in intact form. Soy isoflavones (SIs) show various health benefits, such as antioxidant and estrogenic effects. It is important to understand the bioaccessibility and bioavailability of SIs due to the close relation to their bioactivities. In this study, the antioxidant capacity, bioaccessibility, and bioavailability of 12 SIs were evaluated using radical-scavenging methods, simulations of human digestion, and Caco-2 cells in Transwell, respectively. All SIs were stable (91.1–99.2%) under gastric digestion conditions compared with the control (100%), whereas acetyl and malonyl conjugates were unstable (38.5% and 65.5%, respectively) under small intestinal digestion conditions. SI aglycones showed higher permeability (7–15 times) and cellular accumulation (8.8 times) than their glucosides. A small amount of SI conjugates was intact in the cell and in the basolateral side of each Transwell. These results suggest that SI conjugates, especially malonyl and acetyl forms, have incidental bioactivity after being metabolized to aglycones inside the cell.