Isolation of activating factors of serotonin N -acetyltransferase from rice peptides

Assessment of the biotechnological activity of wheat hydrolysates prepared with the Biarum bovei extract

In this study, Biarum bovei extract was used to produce bioactive peptides from wheat gluten protein and the biological and functional properties of the hydrolysates were determinated. The results showed that Biarum bovei extract has its highest protease activity (7.3 U/mg protein) at 45 °C and pH 5. Based on electrophoresis analysis, the molecular weight of hydrolysate was < 10 kDa. F1 fraction had the highest antioxidant activity in DPPH (65.85 ± 2.64 µmol TE/g)) and ABTS radical scavenging assays (295.81 µmol TE/g). F2 fraction with 86.3 ± 0.48 had the ability to inhibit the ACE enzyme. The F3 and F1 fractions had statistically the highest inhibition rate (49.37 ± 0.12%. and 79.19 ± 1.13%) in alpha-glucosidase and alpha amylase, respectively. The F1, F2 fractions hydrolysate had an inhibitory effect on Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. Functional properties of hydrolysates with increasing molecular weight, increased significantly. The presence of high levels (p ≤ 0.05) of amino acids with hydroxyl groups, hydrophobic and positive charged in fractions had critical role on biological and technological activity. These findings confirmed the efficiency of gluten hydrolysates with low molecular weight (F1 < 3 kDa) on biofunctionality such as scavenging radical activity, ACE inhibitory, antidiabetic and antibacterial activity could be beneficial from health and technological perspectives.

Protective Effects of Rice Peptide Oryza Peptide-P60 against Oxidative Injury through Activation of Nrf2 Signaling Pathway In Vitro and In Vivo

We previously showed that commercially available rice peptide Oryza Peptide-P60 (OP60) increased the intracellular glutathione levels. This study aimed to evaluate the antioxidant potential of this peptide and assess its mechanism of action. Pretreatment of HepG2 cells with OP60 reduced the cytotoxicity caused by H₂O₂ or acetaminophen (APAP) (47.7 ± 1.3% or 12.2 ± 1.3% of the cytotoxicity for 5 mg/mL OP60 pretreatment compared to that in H₂O₂- or APAP-treated groups, respectively; p < 0.01) through the restoration of glutathione homeostasis. Moreover, OP60 elevated the mRNA level of genes encoding heavy and light subunits of γ-glutamylcysteine synthetase (γ-GCS) by 2.9 ± 0.1-fold and 2.7 ± 0.2-fold (p < 0.001), respectively, at 8 h and also increased the level of mRNA encoding other antioxidant enzymes. Besides, OP60 promoted Nrf2 nuclear translocation by 2.2 ± 0.3-fold (p < 0.05) after 8 h. Conversely, knockdown of Nrf2 inhibited the increase of the intracellular glutathione levels and suppressed the induction of antioxidant enzyme expression by OP60. In animal studies, OP60 prevented APAP-induced liver injury by suppressing glutathione depletion (from 0.19 ± 0.02 mmol/mg protein to 0.90 ± 0.02 mmol/mg protein; p < 0.01, by pretreatment with 500 mg/kg OP60) and increasing heavy subunit of γ-GCS and heme oxygenase-1 expression in the liver. Our results indicated that OP60 exhibits a cytoprotective effect via the Nrf2 signaling pathway and is one of the few peptides with excellent antioxidant properties.

Adaptation of the metabolomics profile of rice after Pyricularia oryzae infection

Pyricularia oryzae (P. oryzae), one of the most devastating fungal pathogens, is the cause of blast disease in rice. Infection with a blast fungus induces biological responses in the host plant that lead to its survival through the termination or suppression of pathogen growth, and metabolite compounds play vital roles in plant interactions with a wide variety of other organisms. Numerous studies have indicated that rice has a multi-layered plant immune system that includes pre-developed (e.g., cell wall and phytoanticipins), constitutive and inducible (phytoalexins) defence barriers against stresses. Significant progress towards understanding the basis of the molecular mechanisms underlying the defence responses of rice to P. oryzae has been achieved. Nonetheless, even though the important metabolites in the responses of rice to pathogens have been identified, their exact mechanisms and their contributions to plant immunity against blast fungi have not been elucidated. The purpose of this review is to summarize and discuss recent advances towards the understanding of the integrated metabolite variations in rice after P. oryzae invasion.