School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
Food Chem. 2020 Oct 15;327:127059. doi: 10.1016/j.foodchem.2020.127059. Epub 2020 May 15.
The aim of this study was to purify and identify antioxidant peptides from watermelon seed protein hydrolysates (WSPHs-I: Mw < 1 kDa) and further evaluate their cytoprotective effects against HO-induced oxidative stress in HepG2 cells. After purification by Sephadex G-15 and semi-preparative reversed-phase high performance liquid chromatography (RP-HPLC), five peptides, RDPEER (P1), KELEEK (P2), DAAGRLQE (P3), LDDDGRL (P4), and GFAGDDAPRA (P5) were sequenced by LC-MS/MS and synthesized with solid-phase synthesis method. These peptides showed desirable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity (IC: 0.216 ± 0.01-0.435 ± 0.03), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity (IC: 0.54 ± 0.02-1.23 ± 0.03), and oxygen radical absorbance capacity (ORAC) (82.36 ± 1.2-130.67 ± 2.2 μM TE/mg). Among them, peptide P1 exhibited the strongest antioxidant capacity. Moreover, the results suggested that peptide P1 may protect HepG2 cells from HO-induced oxidative damage by significantly inhibiting reactive oxygen species (ROS), [Ca]i, malondialdehyde (MDA) levels and increasing antioxidative enzyme activities.
本研究旨在从西瓜籽蛋白水解物（WSPHs-I：Mw < 1 kDa）中分离和鉴定具有抗氧化活性的肽，并进一步评估其对 HepG2 细胞中 HO 诱导的氧化应激的细胞保护作用。经 Sephadex G-15 和半制备反相高效液相色谱（RP-HPLC）纯化后，通过 LC-MS/MS 对 5 个肽（P1、P2、P3、P4 和 P5）进行测序，并采用固相合成法进行合成。这些肽表现出良好的 1,1-二苯基-2-苦基肼（DPPH）自由基清除能力（IC：0.216 ± 0.01-0.435 ± 0.03）、2,2'-联氮-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）自由基清除能力（IC：0.54 ± 0.02-1.23 ± 0.03）和氧自由基吸收能力（ORAC）（82.36 ± 1.2-130.67 ± 2.2 μM TE/mg）。其中，肽 P1 表现出最强的抗氧化能力。此外，研究结果表明，肽 P1 可能通过显著抑制活性氧（ROS）、[Ca]i、丙二醛（MDA）水平和提高抗氧化酶活性来保护 HepG2 细胞免受 HO 诱导的氧化损伤。
