Microencapsulation and Peptide identification of purified bioactive fraction from spirulina protein hydrolysates with dipeptidyl peptidase IV (DPP-IV) inhibitory activity

The growing worldwide occurrence of type 2 diabetes mellitus (T2DM) necessitates the development of effective treatments. This study presents a comprehensive investigation into the inhibitory effect of trypsin-digested Spirulina protein hydrolysate (SPH) on the dipeptidyl peptidase IV (DPP-IV) enzyme, responsible for deactivating incretin hormones that stimulate insulin secretion. Following purification through hydrophobic interaction chromatography, the DPP-IV inhibition potential was enhanced, achieving a level of 74.20% ± 5.78%, with a half-maximal inhibitory concentration (IC50) value of 0.46 ± 0.16 mg/ml. By subsequently encapsulating the purified SPH within alginate and chitosan microcapsules, a controlled and sustained release profile of bioactive peptides was achieved while retaining their DPP-IV inhibitory activity. The encapsulation process exhibited an efficiency of 86.30% ± 0.16% and an efficacy of 80.65% ± 0.16% for SPH loading. Further analysis via LC-MS/MS revealed a potent peptide, GPNYASSER, derived from phycocyanin, exhibiting an IC50 value of 0.358 ± 0.188 mM. Beyond the search for specific peptides displaying strong DPP-IV inhibitory properties, the integration of SPH as function components for Type 2 Diabetes Mellitus (T2DM) management holds significant promise as a pathway for long-term preventive strategies.