Purification and Identification of Pine Nut (Pinus yunnanensis Franch.) Protein Hydrolysate and Its Antioxidant Activity in Vitro and in Vivo

Abstract

In this study, the pine nut (Pinus yunnanensis Franch.) protein was hydrolyzed by alkaline protease and trypsin to prepare pine nut protein hydrolysate (PNPH). The chemical, intracellular and in vivo antioxidant capacity of PNPH were evaluated. PNPH owned the ability of scavenging free radicals, and it could protect the HepG2 cells from oxidative damage by preserving cell viability. Moreover, PNPH could reduce the malondialdehyde (MDA) content and improved the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum, heart and liver of aging mice induced by D-galactose. Further, the PNPH was stepwise purified and identified, and 15 peptides were identified from purified fraction in PNPH. The three-dimension structures of identified peptides were predicted. Among all identified peptides, peptide 3, 7, 8 and 11 were presumed to possess good antioxidant activity. Overall, PNPH and purified peptides isolated from PNPH have potential application prospects in the field of natural antioxidants and anti-aging functional foods.

Advances on the Antioxidant Peptides from Nuts: A Narrow Review

“…Moreover, there were 29 peptides which contained basic amino acid residues and 19 peptides which contained acidic amino acids ( Table 6 ). The acidic amino acids (Asp and Glu) and basic amino acids (His, Arg, and Lys) can quench unpaired electrons and radicals by using carbonyl and amino groups in the side chain as chelators of metal ions [ 94 ]. Liu et al reported that hazelnut-derived antioxidant peptide with an amino sequence of Asp-Trp-Asp-Pro-Lys involving two acidic amino acids, one basic amino acid, one aromatic amino acid, and two hydrophobic amino acids, possessed high ABTS and DPPH scavenging capacity [ 39 ].…”

Bioactive peptides from nuts: A review

“…Pine nut meal is an agro‐industrial waste rich in protein remaining from the process of oil extraction. Pine nut protein hydrolysate (PNPH) has shown free radical scavenging activity, mitigating cell oxidative stress, along with a reduction in the lipid peroxidation and an increase in the SOD and GSH‐Px activities (Liu et al ., 2021).…”

Transepithelial transport and cellular mechanisms of food-derived antioxidant peptides

“…Two peptides, WSREEQEREE and ADIYTEEAGR, were found to retain the anti-photoaging properties of the walnut protein hydrolysates and they acted by downregulating gene expression of inflammatory cytokines (interleukins (IL)-1β and IL-6) and inhibiting MMP-1 activity and the phosphorylation of IκB and p-65 proteins, which are activators of the NF-κB/MMPs signaling pathway [ 83 ]. Similarly, pine nut-derived peptides (MQIFVK, MASVPTK, EMVELPLR and VVLIGDSGVGK) reduced D-galactose-induced premature aging in mice by suppressing lipid peroxidation and enhancing the activities of SOD and GPx in mouse serum, and heart and liver homogenates [ 84 ]. The ability to boost the activities of antioxidant enzymes (CAT, GSH, SOD and GPx) ( Figure 1 ), inhibit lipid peroxidation (malondialdehyde [MDA]) and protein oxidation (protein carbonyl), and downregulate gene expression of MMPs in mice have been reported as the antioxidant mechanisms of other FDAPs in preventing UV radiation-induced skin photoaging [ 83 , 85 , 86 , 87 ].…”

“…The peptide also up-regulated gene expression of tumor suppressor gene (Bcl-2) and HO-1 via the PI3K/Akt/mTor//Nrf2/ARE pathway, and reduced oxidant-mediated ROS production in endothelial cells, leading to the amelioration of endothelial oxidative damage and atherogenesis in high fat fed ApoE-deficient mice ( Figure 1 ). Several other FDAPs (AYI, AYL, DREI, DREL, MQIFVK, MASVPTK, EMVELPLR, VVLIGDSGVGK and LEPVIGT) were recently demonstrated to protect HepG2 cells via the Keap1/Nrf2/ARE signaling pathway, leading to the upregulation of gene expression of antioxidant enzymes and ROS detoxification pathways [ 84 , 102 , 103 ]. Similar mechanisms were demonstrated by a dipeptide (IF) from potato protein hydrolysates in hypertension-generated ROS-induced renal damage in rats [ 104 ].…”

“… Peptide/protein hydrolysate Oxidative stress model Cellular mechanism of action Ref WSREEQEREE and ADIYTEEAGR from walnut protein UV-radiation-induced mouse skin aging Suppressed NF-κB signaling pathway by preventing the activation of IκB and p-65 proteins, downregulated gene expression of interleukins (IL)-1β and IL-6, inhibited MMP-1 activity and enhanced the expression of TGF-β and procollagen type I. [ 155 ] GAGLPGKRER from Pinctada fucata protein hydrolysates UV-radiation-induced mouse skin aging Inhibited CAT, glutathione system and SOD activities, halted lipid peroxidation and suppressed UV-radiation-induced skin aging [ 86 , 130 ] PELDW, WPDHW, FGYDWW, and YLHFW isolated from Spanish Mackerel muscle H 2 O 2 -generated plasmid DNA damage Inhibited DNA damage by boosting the antioxidant status and preventing uncoiling and strand break [ 156 ] MQIFVK, MASVPTK, EMVELPLR and VVLIGDSGVGK derived from pine nut H 2 O 2 -challenged HepG2 cells and D-galactose-induced premature aging in mouse Improved the viability of HepG2 cells, and suppressed lipid peroxidation and enhanced antioxidant status by increasing SOD and GPx activity in mouse [ 84 ] LEPVIGT derived from porcine plasma H 2 O 2 -induced oxidative stress in HepG2 cells Protected HepG2 cells via Keap1-Nrf2-ARE signaling pathway [ 103 ] FYY and DW derived from lantern fish protein D-galactose-induced aging Suppressed lipid peroxidation level and expression of endothelial nitric oxide synthase, and improved memory impairment by elevating brain-derived neurotrophic factor [ 92 ] DVEDLEAGLAK and EITSLAPSTM from golden cuttlefish High fat Caenorhabditis elegans Prevented oxidative damage via upregulation of mRNA expression of DAF-16 signaling pathway-regulated genes (sod-3, catalase (cat-1) and ctl-1)) [ 54 ] AYI, AYL, DREI and DREL from Jiuzao 2,2′-Azobis(2-methylpropanimidamidine)-stressed HepG2 cells inhibited ROS generation, elevated SOD, CAT and GPx gene expression and improved the viability of HepG2 cells via Keap1-Nrf2-ARE signaling pathway [ ...…”