Isolation, purification and characterization of the antibacterial, antihypertensive and antioxidative properties of the bioactive peptides in the purified and proteolyzed major storage protein of pigeon pea (Cajanus cajan) seeds

Abstract

Previous studies in pigeon pea showed health benefits but very few explored peptide bioactivities. This study examined antimicrobial, antioxidant, and antihypertensive activities of peptides in purified and proteolyzed major globulin fraction, cajanin, of pigeon pea (Cajanus cajan) seeds. In-silico analysis showed 41 antihypertensive and nine antioxidant peptides but zero antibacterial peptides from cajanin sequence. The Pepsin-Chymotrypsin-Trypsin (PCT) protein digest has no antibacterial activity against Escherichia coli, Candida albicans, and Staphylococcus aureus but has high % ACE inhibition (87.50%). Two HPLC fractions showed low IC50 values (HPLC Fraction 1: 0.00535 mg/ml; HPLC Fraction 2: 0.00432 mg/ml), comparable to Captopril (0.00379 mg/ml). This fractions also showed H2O2 scavenging activity (HPLC Fraction 1: 1.47%; HPLC Fraction 2: 1.51%) and Total Antioxidative Capacity of 0.00088 mg/mL (HPLC Fraction1) and 0.00110 mg/mL (HPLC Fraction 2) ascorbic acid equivalent. Results from this study serve as reference for further investigations of novel pharmaceutical agents that can be derived from legumes.