Purification and Identification of Antioxidant Peptides from Protein Hydrolysate of Scalloped Hammerhead (Sphyrna lewini) Cartilage.

Xue-Rong Li,Chang-Feng Chi,Li Li,Bin Wang

doi:10.3390/md15030061

Abstract

The aim of this study was to purify and identify peptides with antioxidant properties from protein hydrolysate of scalloped hammerhead (Sphyrna lewini) cartilage. Cartilaginous proteins of the scalloped hammerhead were extracted by guanidine hydrochloride, and three antioxidant peptides, named enzymolysis peptide of scalloped hammerhead cartilage A (SCPE-A), SCPE-B and SCPE-C, were subsequently isolated from the hydrolysate of the cartilaginous proteins using ultrafiltration and chromatography. The amino acid sequences of SCPE-A, SCPE-B and SCPE-C were identified as Gly-Pro-Glu (GPE), Gly-Ala-Arg-Gly-Pro-Gln (GARGPQ), and Gly-Phe-Thr-Gly-Pro-Pro-Gly-Phe-Asn-Gly (GFTGPPGFNG), with molecular weights of 301.30 Da, 584.64 Da and 950.03 Da, respectively. As per in vitro activity testing, SCPE-A, SCPE-B and SCPE-C exhibited strong scavenging activities on 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH•) (half elimination ratio (EC50) 2.43, 2.66 and 1.99 mg/mL), hydroxyl radicals (HO•) (EC50 0.28, 0.21 and 0.15 mg/mL), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radicals (ABTS+•) (EC50 0.24, 0.18 and 0.29 mg/mL), and superoxide anion radicals (•) (EC50 0.10, 0.14 and 0.11 mg/mL). In addition, SCPE-A showed inhibition activity similar to butylated hydroxytoluene (BHT) in lipid peroxidation in a linoleic acid model system. The amino acid residues of Gly, Pro and Phe could positively influence the antioxidant activities of GPE, GARGPQ and GFTGPPGFNG. These results suggested that GPE, GARGPQ and GFTGPPGFNG might serve as potential antioxidants and be used as food additives and functional foods.

Highlights

Oxidation is an important factor in the food industry because it causes a loss of nutrition, color and functionality, as well as undesirable off-flavors and toxic compounds, which further induce the deterioration of food
Proteins in raw and processed foods possess antioxidant peptide sequences and structural domains, and enzymatic hydrolysis is considered as an attractive way for releasing those active fragments without impairing their nutritional value and without leaving residual organic solvents and toxic chemicals in the final product [22]
Protein hydrolysates using different proteases exhibit different antioxidant activities against various antioxidant systems because the peptides are different in terms of chain length and amino acid sequence [1,23]

Summary

Introduction

Oxidation is an important factor in the food industry because it causes a loss of nutrition, color and functionality, as well as undesirable off-flavors and toxic compounds, which further induce the deterioration of food. The accumulation of toxic products is dangerous to the health of consumers [1,2]. The inhibition of free radical formation and oxidation reactions play an important role in preventing or retarding the autoxidation of food components [3]. Many synthetic antioxidants, including butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertiary butylhydroquinone (TBHQ), are widely used in the food industry for preservation and to retard lipid oxidation [4,5]. The dosages of the synthetic antioxidants are under strict regulation due to. Mar. Drugs 2017, 15, 61; doi:10.3390/md15030061 www.mdpi.com/journal/marinedrugs

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