Sakinah Hilya Abida, Christoper Caesar Yudho Sutopo, Wei-Ting Hung, Nhung Thi Phuong Nong, Tunjung Mahatmanto, Jue-Liang Hsu
The tree bean (Parkia timoriana), an underutilized legume valued for its nutritional profile, represents a potential source of bioactive peptides for diabetes management. To our knowledge, this is the first study to identify and characterize DPP-IV inhibitory peptides derived from tree bean seed protein hydrolysates. The tree bean proteins were digested with trypsin, thermolysin, chymotrypsin, pepsin, and simulated gastrointestinal (SGI) enzymes, among which SGI hydrolysis yielded the highest degree of hydrolysis (14%) and strongest DPP-IV inhibitory activity (IC50 = 1289 ± 58 µg/mL). Guided by DPP-IV inhibitory assays, sequential fractionation using strong cation exchange and RP-HPLC yielded the most potent fraction, H5, with an IC50 of 949 ± 50 µg/mL. After peptide identification and synthesis, APLGPF (AF6) emerged as the most potent inhibitor, with an IC50 of 396 ± 18 µM. Enzyme kinetics revealed a non-competitive inhibition mechanism, corroborated by molecular docking, which indicated binding at an allosteric site of DPP-IV. Furthermore, AF6 remained stable under simulated gastrointestinal digestion and enzymatic exposure, highlighting its resistance to proteolysis. Taken together, these findings highlight P. timoriana as an underexplored source of peptides with DPP-IV inhibitory activity and identify AF6 as a promising lead for developing functional foods or nutraceuticals aimed at type 2 diabetes management. © 2025 by the authors.
Department of Biological Science and Technology, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan; Department of Food Science and Biotechnology, Faculty of Agricultural Technology, Universitas Brawijaya, Jl. Veteran, Malang, 65145, Indonesia; Department of Animal Science and Technology, National Taiwan University, Taipei, 106037, Taiwan; Institute of Biotechnology and Food Technology, Thai Nguyen University of Agriculture and Forestry, Thai Nguyen, 25000, Viet Nam
