Antioxidant and antiproliferative activities of peptide from SEA LETTUCE Ulva rigida

Abstract

The purpose of this study was to preparation protein hydrolysates from sea lettuce by enzymatic hydrolysis of three microbial proteases (alcalase, flavourzyme, and neutrase) and investigates antioxidant activity by determination of the DPPH, ABTS, and NO scavenging activity. The result showed protein hydrolysate by five percent flavourzyme exhibited higher antioxidant activities than those other enzymes. These peptides were fractionated by ultrafiltration and gel filtration chromatography, low molecular weight (F5) of peptide was the highest antioxidant activity. Peptide fractions were observed for their antioxidant activities including enzymatic SOD, Catalase and GPx scavenging activity. Additionally, using cytotoxicity activity was determined by MTT assay in five cell lines. The results revealed that F5 had more inhibition against the proliferation of KATO-III cell lines and SW620 cell lines. The F5 could induce apoptosis cells in KATO-III cell lines of IC50=1.23 µg/ml and SW620 cell lines of IC50=1.00 µg/ml. These peptides were identified by HPLC technique and mass spectrometry as 4 peptide chains. All peptide chains contain hydrophobic amino acids (Pro, Leu, Ala, Trp and Phe) and some peptide chain had aromatic amino acids (Phe, Trp and Tyr) to possess high antioxidant activity. However, sea lettuce stills a good source of natural antioxidant and might be used in future.