Investigation of functional, antioxidant, anti-inflammatory, and antidiabetic properties of legume seed protein hydrolysates

Plant-derived hydrolysates are emerging as promising agents in the management of diverse ailments due to their ensuing functional and bioactive properties. This study investigated the functional, antioxidant, anti-inflammatory, and antidiabetic properties of hydrolysates from Erythrina senegalensis and Vigna subtenarrea seeds. Crude proteins were isolated via alkaline solubilization, followed by acid precipitation to the isoelectric point. Respective protein isolates were hydrolyzed using trypsin and pepsin at an enzyme-substrate ratio of 1:8 (v/v) for 1–9 h. Pepsin hydrolysates after 9 h elicited the highest solubilities of 95.54 % and 94.24 % at pH 13, while, pepsin and trypsin hydrolysates of E. senegalensis digested for 1 and 9 h displayed the highest 1,1-diphenyl-2-picrylhydrazyl radical-scavenging (10-IC₅₀ = 2.959 mg/mL) and total antioxidant capacity (7.243 mgAAE/g), respectively. Correspondingly, pepsin and trypsin hydrolysates of E. senegalensis hydrolyzed for 5 h demonstrated the most potent anti-inflammatory activities by cogently inhibiting xanthine oxidase and lipoxygenase activities with IC₅₀ of 0.161 ± 0.111 and 0.018 ± 0.011 mg/mL, respectively. Trypsin hydrolysates of V. subterranea hydrolyzed for 5 h potently inhibited the activities of α-amylase and α-glucosidase with respective IC₅₀ of 0.297 ± 0.060 and 0.314 ± 0.064 mg/mL. Overall, pepsin and trypsin hydrolysates of E. senegalensis demonstrated pronounced functional bioactivities relative to V. subterranea hydrolysates. This study concludes that both seeds could serve as unique matrices of potential functional bioactive peptides with prospects for managing diabetes.