Oxidative Stress Amelioration of Novel Peptides Extracted from Enzymatic Hydrolysates of Chinese Pecan Cake
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MDPI
Materia
Chinese pecan by-products Antioxidant peptides Proline content Molecular docking Keap1-Nrf2-ARE pathway
Date
2022-10-11Referencia bibliográfica
Zhang, J... [et al.]. Oxidative Stress Amelioration of Novel Peptides Extracted from Enzymatic Hydrolysates of Chinese Pecan Cake. Int. J. Mol. Sci. 2022, 23, 12086. [https://doi.org/10.3390/ijms232012086]
Sponsorship
People's Government of Zhejiang Province; Chinese Academy of Forestry 2019SY03; Natural Science Foundation of Xinjiang Uygur Autonomous Region 2021D01A71Abstract
Pecan (Carya cathayensis) is an important economic crop, and its hydrolyzed peptides have
been evidenced to reduce the effect of oxidative stress due to their antioxidant capacity. Hence, the
protocols of ultrafiltration and gel filtration chromatography were established to obtain bioactive
peptides from by-products of C. cathayensis (pecan cake). As measured by DPPH/ABTS radical
scavenging, the peptides with less molecular weight (MW) possess higher antioxidant capacity. PCPHIII
(MW < 3 kDa) presented higher radical scavenging capacity than PCPH-II (3 kDa < MW < 10 kDa)
and PCPH-I (MW > 10 kDa) measured by DPPH (IC50: 111.0 g/ mL) and measured by ABTs (IC50:
402.9 g/mL). The secondary structure and amino acid composition varied by their MW, in which
PCPH-II contained more -helices (26.71%) and -sheets (36.96%), PCPH-III contained higher ratios
of -turns (36.87%), while the composition of different secondary of PCPH-I was even 25 5.76%.
The variation trend of -helix and random experienced slightly varied from PCPH-I to PCPH-II, while
significantly decreased from PCPH-II to PCPH-III. The increasing antioxidant capacity is followed
by the content of proline, and PCPH-III had the highest composition (8.03%). With regard to the
six peptides identified by LC-MS/MS, two of them (VYGYADK and VLFSNY) showed stronger
antioxidant capacity than others. In silico molecular docking demonstrated their combining abilities
with a transcription factor Kelch-like ECH-associated protein 1 (Keap1) and speculated that they
inhibit oxidative stress through activating the Keap1-Nrf2-ARE pathway. Meanwhile, increased
activity of SOD and CAT—antioxidant markers—were found in H2O2-induced cells. The residue of
tyrosine was demonstrated to contribute the most antioxidant capacity of VYGYADK and its position
affected less. This study provided a novel peptide screening and by-product utilization process that
can be applied in natural product developments.