Preliminary Assessment of the Antihypertensive and Antioxidative Activities of the Peptides from “Saba” Banana (Musa balbisiana Colla) Flesh

The crude proteins were isolated using 0.125 M Tris-HCl with 50 mM NaCl at pH 7.4. The protein content of the crude extract was determined using the Lowry assay and was found to be 4.28 mg/mL.  The major band which corresponds to the major protein has an approximate molecular weight of 20 KDa. The isolated crude proteins were subjected to enzymatic digestion using pepsin, trypsin, chymotrypsin, and thermolysin for 3, 4, 12, and 24 hours. The 24-hour digest was found to have the highest percent anti-Angiotensin Converting Enzyme (ACE) activity (36.02%) while the 12-hour digest was found to have the highest anti-oxidative activity (33.14%) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The 24-hour digest was subjected to Ultra-Performance Liquid Chromatography (UPLC) to determine the peptide fraction responsible for the ACE inhibitory activity. Three peptide fractions (PF1, PF2 and PF3) were chosen and PF2 exhibited the highest percent inhibitory activity (32.21) against ACE. PF2 was subjected to thin layer chromatography (TLC) and the possible identity is EK based on the Rf value traveled by glutamic acid (E) (0.43) and Lysine (K) (0.13). In silico analysis was done to correlate the results with the presence of putative peptides with antioxidative and antihypertensive activities. Results showed that antihypertensive peptides EK, GS, TY, FNE, FP, LKA, PT, PP, FAL and antioxidative peptides IR and VPW were found based on the sequence of the protein in “Saba” banana. The presence of the antihypertensive peptide EK was verified using thin layer chromatography (TLC).