Identification and antioxidant activity of synthetic peptides from phycobiliproteins of Pyropia yezoensis

Abstract

The objective of the present study was to identify peptides, based on active components of the red algae seaweed Pyropia yezoensis, able to inhibit the generation of reactive oxygen species (ROS), which is associated with aging and oxidative activities. Phycobilin, specific to red algae, covalently binds with water-soluble proteins. There are three types of pigment bound proteins, known as phycobiliproteins (PBPs): Phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC). In the present study, PBPs reported previously to have antioxidant activities in P. yezoensis were identified and, based on these data, several peptides were synthesized (PBP 1-13) and their inhibition of ROS generation was examined. The existence of PBPs of each type, PE, PC and APC, was established in P. yezoensis and all were analyzed. In addition, PBP 1-2 and 7-9 peptides from PE were synthesized and showed antioxidant activities in HepG2 cells. In HepG2 cells, treatment with PBP2 reduced hydrogen peroxide-mediated oxidative stress and restored the expression of superoxide dismutase (SOD). Furthermore, phosphorylated nuclear factor erythroid-derived 2-like 2 (Nrf2) was elevated by PBP2 treatment. Overall, these results suggested that Nrf2-SOD pathways may be involved in the PBP2-mediated antioxidant effects. Therefore, from the investigations of P. yezoensis, several candidate peptides were identified with promising antioxidant and, potentially, anti-aging properties.

Seaweeds as a Source of Functional Proteins

“…Reactive oxygen species (ROS) contribute to the development of chronic diseases, including cardiovascular diseases, cancer, diabetes mellitus, cataracts, and neurodegenerative disorders [116]. ROS includes free radical species, such as superoxide anions, hydroxyl radicals, and singlet oxygen, and non-radical species, such as hydrogen peroxide (H 2 O 2 ), generated during the metabolic process [145]. The antioxidant activity of bioactive peptides is attributed to the hydrophobicity of valine, leucine, isoleucine, glycine, methionine, proline, and alanine and some aromatic amino acids (tyrosine, histidine, tryptophan, and phenylalanine) [116].…”

A Critical Review of the Abilities, Determinants, and Possible Molecular Mechanisms of Seaweed Polysaccharides Antioxidants

“…When exposed to oxidant stress, the Keap1-Cul3 complex normally linked to Nrf2 is dissociated because of the modifications of Keap1 [ 10 ]. Nrf2 bound to ARE accumulates, promoting the production of the corresponding downstream phase II detoxifying enzymes and antioxidative proteins (e.g., superoxide dismutase-1 (SOD-1), hemeoxygenase-1 (HO-1), Glutamylcysteine synthetase (γ-GCS)) [ 9 , 138 , 139 ]. Ryu and Chung investigated the molecular mechanisms of fucoidan in the protection of human keratinocytes (HaCaT cells) from mild oxidative stress, indicating that the expression levels of HO-1, SOD-1, and Nrf2 are positively time-dependent following fucoidan treatment, whereas Keap1 expression was the opposite [ 140 ].…”

Regioselective syntheses and analyses of phlorofucofuroeckol‐A derivatives

“…[7][8][9][10] PFF-A has a unique pentacyclic sub-structure including the dibenzo-p-dioxin skeleton and shows antioxidant, 11,12 anticancer, [13][14][15] anti-inflammatory, [16][17][18] antidiabetic, 19 antibacterial, 20 anti-allergic inflammation, 21 and antifibrotic effects. 22 Recently, bioactivities related to cytogenesis such as adipogenesis interference 23 and osteoblast production 24 as well as effects on brain and nervous system diseases such as Alzheimer's disease, 25,26 Parkinson's disease, 27 and stroke 28 have also been reported. Moreover, PFF-A and other eckol compounds are edible, [29][30][31] possibly allowing their applications as therapeutic agents that can be administered not only by injection but also by orally for various diseases.…”