Cordycepin Enhances the Cytotoxicity of Human Natural Killer Cells against Cancerous Cells.

Cancer treatment with natural killer (NK) cell immunotherapy is promising. NK cells can recognize and kill cancer cells without sensitization, making them a potential cancer treatment alternative. To improve clinical efficacy and safety, more research is needed. Enhancing NK cell function improves therapeutic efficacy. Due to its potent apoptosis induction, Cordycepin, a bioactive compound from Cordyceps spp., inhibits cancer cell growth. Cordycepin has immunoregulatory properties, making it a promising candidate for combination therapy with NK cell-based immunotherapy. Cordycepin may enhance NK cell function and have clinical applications, but more research is needed. In this study, cordycepin treatment of NK-92 MI cells increased THP-1 and U-251 cell cytotoxicity. Cordycepin also significantly increased the mRNA expression of cytokine-encoding genes, including tumour necrosis factor (TNF), interferon gamma (IFNG), and interleukin 2 (IL2). NK-92 MI cells notably secreted more IFNG and granzyme B. Cordycepin also decreased CD27 and increased CD11b, CD16, and NKG2D in NK-92 MI cells, which improved its anti-cancer ability. In conclusion, cordycepin could enhance NK cell cytotoxicity against cancerous cells for the first time, supporting its use as an alternative immunoactivity agent against cancer cells. Further studies are needed to investigate its efficacy and safety in clinical settings.

Development of an animal-free nitrogen source for the liquid surface culture of Cordyceps militaris.

Cordyceps militaris is a medicinal mushroom in Asia in the 21st century, which cordycepin is a significant bioactive compound. This study, investigated the effect of culture conditions and vegetable seed extract powder as a supplementary source of animal-free nitrogen on the production of cordycepin by C. militaris in liquid surface culture. The highest cordycepin production was observed under soybean extract powder (SBEP) conditions, and 80 g L-1 of SBEP supplementation increased cordycepin production to 2.52 g L-1, which was greater than the control (peptone). Quantitative polymerase chain reaction was used to examine the transcription levels, and the results showed that supplementing with SBEP 80 g L-1 significantly increased the expression of genes associated with the carbon metabolic pathway, amino acid metabolism, and two key genes involved in the cordycepin biosynthesis (cns1 and NT5E) compared to peptone-supplemented culture. Under optimal culture conditions, the model predicted a maximum response of cordycepin production of 2.64 g L-1 at a working volume of 147.5 ml, an inoculum size of 8.8% v/v, and a cultivation time of 40.0 days. This optimized culture condition could be used to increase cordycepin production in large-scale bioreactors. Additional research can be conducted to assess the economic viability of this process.

Cordycepin, a bioactive compound from Cordyceps spp., moderates Alzheimer's disease-associated pathology via anti-oxidative stress and autophagy activation.

Alzheimer's causes cognitive dysfunction. This study investigated the neuro-promoting effects of cordycepin on amyloid-beta precursor protein (APP) synthesis in human neuroblastoma SH-SY5Y cells. Cordycepin was found to boost SH-SY5Y cell proliferation and decreased AD pathology. APP, PS1, and PS2 were downregulated whereas ADAM10 and SIRT1 were upregulated by cordycepin. Cordycepin also reduced APP secretion in a dose-dependent manner. Cordycepin alleviated oxidative stress by the upregulation of GPX and SOD, as well as autophagy genes (LC3, ATG5, and ATG12). Cordycepin activity was also found to be SIRT1-dependent. Therefore, cordycepin may relieve the neuronal degeneration caused by APP overproduction, and oxidative stress.

Nanoencapsulated cordyceps extract enhances collagen synthesis and skin cell regeneration through antioxidation and autophagy.

Oxidative stress from reactive oxygen species is the main cause of skin ageing. Cordycepin, a bioactive compound of Cordyceps militaris, contains antioxidant activity. This study examined extracellular matrix, antioxidant effect, autophagy activity, and skin regeneration in human dermal fibroblasts (HDFs) under normal and oxidative stress conditions. Slow disintegration was used to create nano-encapsulated cordyceps extract. HDFs were cultured and treated with 1 M cordycepin, 1 M medium, 0.1 M cordyceps medium loaded nanoparticles (CMP), or 1 mM H2O2. HDFs' senescent phenotypes were assessed, including cell proliferation, ROS scavenging, collagen and elastin synthesis, antioxidant activity, and wound healing. CMP size averaged 184.5 ± 95.2 nm increased cell proliferation and reduced H2O2-induced ROS. Thus, HDFs treated for 48 h increased skin regeneration activity 2.76-fold by expressing extracellular matrix and rescuing H2O2-induced damaged cells. It was significant that this CMP inhibited H2O2-induced oxidative stress and induced autophagy to regenerate HDFs. The developed CMP could be used in cosmetics.

Combination of Melatonin and Small Molecules Improved Reprogramming Neural Cell Fates via Autophagy Activation.

Reprogramming cell fates towards mature cell types are a promising cell supply for treating degenerative diseases. Recently, transcription factors and some small molecules have turned into impressive modulating elements for reprogramming cell fates. Melatonin, a pineal hormone, has neuroprotective functions including neural stem cell (NSC) proliferative and differentiative modulation in both embryonic and adult brain. We developed a protocol that could be implemented in the direct reprogramming of human skin fibroblast towards neural cells by using histone deacetylase (HDAC) inhibitor, glycogen synthase kinase-3 (GSK3) inhibitor (CHIR99021), c-Jun N-terminal kinase (JNK) inhibitor, rho-associated protein kinase inhibitor (Y-27632), cAMP activator, and melatonin treatment. We found that melatonin enhanced neural-transcription factor genes expressions, including brain-specific homeobox/POU domain protein 2 (BRN2), Achaete-Scute Family BHLH transcription Factor 1 (ASCL1), and Myelin Transcription Factor 1 Like (MYT1L). Melatonin also increased the expression of different neural-specific proteins such as doublecortin (DCX), Sex determining region Y-box 2 (Sox2), and neuronal nuclei (NeuN) compared with other five small molecules (valproic acid (VPA), CHIR99021, Forskolin, 1,9 pyrazoloanthrone (SP600125), and Y-27632) combination in the presence and absence of melatonin. A noticeable upregulation of autophagy proteins (microtubule-associated protein 1A/1B-light chain 3 (LC3) and Beclin-1) were seen in the melatonin treatment during the induction period while these were reverted in the presence of L-leucine, an autophagy inhibitor. In addition, the expression of NeuN was also significantly reduced by L-leucine. Collectively, our findings revealed an activation of autophagy during neural induction; melatonin enhanced reprogramming efficiency for neuron induction through the modulation of autophagy activation.

Indomethacin-based near-infrared photosensitizer for targeted photodynamic cancer therapy.

Near-IR fluorescent sensitizers based on heptamethine cyanine (Cy820 and Cy820-IMC) were synthesized and their abilities to target and abolish tumor cells via photodynamic therapy (PDT) were explored. Some hepthamethine cyanine dyes can be transported into cancer cells via the organic anion transporting polypeptides (OATPs). In this study, we aimed to enhance the target ability of the sensitizer by conjugation Cy820 with indomethacin, a non-steroidal anti-inflammatory drug (NSAID), to obtain Cy820-IMC that aimed to target cyclooxygenase-2 (COX-2) which overexpresses in cancer cells. The results showed that Cy820-IMC internalized the cancer cells faster than Cy820 which was verified to be related to COX-2 level and OATPs. Based on PDT experiments, Cy820-IMC has higher photocytotoxicity index than Cy820, >7.13 and 4.90, respectively, implying that Cy820-IMC showed better PDT property than Cy820. However, Cy820 exhibits slightly higher normal-to-cancer cell toxicity ratio than Cy820-IMC, 6.58 and 3.63, respectively. Overall, Cy820-IMC has superior cancer targetability and enhanced photocytoxicity. These characteristics can be further improved towards clinically approved sensitizers for PDT.

Enhancement of cordycepin production from Cordyceps militaris culture by epigenetic modification.

Cordycepin (3'-deoxyadenosine) is a nucleoside analogue and biosynthesised by Cordyceps militaris, an entomopathogenic fungus. In this study, an epigenetic modifier was applied to static liquid cultures to enhance cordycepin production. C. militaris was cultured in a static liquid culture, and valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, was supplemented in order to modifying the epigenetic status. Gene regulatory network was explored to understand the molecular mechanisms underlying cordycepin production. 50 micromolar of VPA enhanced cordycepin production by 41.187% via the upregulation of 5'-nucleotidase, adenylate kinase, phosphorybosyltransferase, Cns1, Cns2, Cnsa3, and Cns4 of C. militaris for at least 2 days after VPA treatment. The maximum production of cordycepin was 2,835.32 ± 34.35 mg/L in 400 mL-working volume. A scaled-up culture was established with a working volume of 10 L, which led to the slight decrease of cordycepin production. This might due to multifactorial effects, for instance limited aeration and an uneven dispersion of nutrients in the culture system. This scaled-up culture was still needed further optimization. The modification of epigenetic status by VPA significantly enhanced cordycepin production by altering key gene regulatory network of C. militaris. The strategy established in this study might be applicable to other microorganism culture in order to improving the production of bioactive compounds. This work aimed to enhance the production of cordycepin by modifying the epigenetic status of C. militaris, in which subsequently altered gene regulatory network of cordycepin biosynthesis pathway. The weekly supplementation of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, significantly improve cordycepin production over 40%, compared to the untreated control, and the gene regulatory network of C. militaris was also adapted.

Cordycepin-loaded Nanoparticles from Cassava Starch Promote the Proliferation of Submandibular Gland Cells and Inhibit the Growth of Oral Squamous Carcinoma Cells.

This study examined associations between the effect of treatment with nano-cassava starch that contained cordycepin (CS) extract, targeting human submandibular gland cells (HSGs), and human oral squamous carcinoma cells (HSC-4). Cassava starch nanoparticles (CSNPs) were prepared by either physical or acid treatment. These nanoparticles were then loaded with either CS or cordyceps medium and then treated with HSG or HSC-4 cells in different concentrations of CS and nanoparticles. Moreover, the protein secretion, reactive oxygen species (ROS) activity and the expression of salivary-specific genes, antioxidant gene were determined after treatment. CSNPs can enhance the activity of CS at low concentrations. Cordycepin-loaded cassava starch nanoparticles (CCSNPs) increased HSG proliferation, protein secretion, and the expression of salivary-specific genes, AMY and AQP5. Besides, CCSNPs also protected and scavenged of ROS via the stimulation of the antioxidant genes in HSGs, indicating the protective roles of CS to HSGs. On the other hand, CCSNPs inhibited the growth of HSC-4 cells by stimulating ROS generation and reducing protein secretion. This finding suggested that CCSNPs presented the dual actions against HSGs and human oral squamous carcinoma cells, and the encapsulation of CS with cassava nanoparticles enhanced the activity of CS.

Flavylium-Based Hypoxia-Responsive Probe for Cancer Cell Imaging.

A hypoxia-responsive probe based on a flavylium dye containing an azo group (AZO-Flav) was synthesized to detect hypoxic conditions via a reductase-catalyzed reaction in cancer cells. In in vitro enzymatic investigation, the azo group of AZO-Flav was reduced by a reductase in the presence of reduced nicotinamide adenine dinucleotide phosphate (NADPH) followed by fragmentation to generate a fluorescent molecule, Flav-NH2. The response of AZO-Flav to the reductase was as fast as 2 min with a limit of detection (LOD) of 0.4 µM. Moreover, AZO-Flav displayed high enzyme specificity even in the presence of high concentrations of biological interferences, such as reducing agents and biothiols. Therefore, AZO-Flav was tested to detect hypoxic and normoxic environments in cancer cells (HepG2). Compared to the normal condition, the fluorescence intensity in hypoxic conditions increased about 10-fold after 15 min. Prolonged incubation showed a 26-fold higher fluorescent intensity after 60 min. In addition, the fluorescence signal under hypoxia can be suppressed by an electron transport process inhibitor, diphenyliodonium chloride (DPIC), suggesting that reductases take part in the azo group reduction of AZO-Flav in a hypoxic environment. Therefore, this probe showed great potential application toward in vivo hypoxia detection.

Cordycepin attenuates Salivary Hypofunction through the Prevention of Oxidative Stress in Human Submandibular Gland Cells.

Xerostomia (dry mouth) is a significant age-related condition. Meanwhile, cordycepin, the natural therapeutic agent, has demonstrated an anti-aging effect. Therefore, the present study aimed to investigate the preventive effects of cordycepin on secretory function in an in vitro model of hydrogen peroxide (H2O2)-induced salivary hypofunction. After being exposed to H2O2, human submandibular gland (HSG) cells were treated with various concentrations of cordycepin (6.25-50 µM) for 24, 48, and 72h. To evaluate cell proliferation and reactive oxygen species (ROS) generation, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and 2, 7'-dichlorodihydrofluorescein diacetate assays were performed. The amylase activity was kinetically measured by 2-chloro-p-nitrophenol linked with maltotrioside. The expression of salivary, antioxidant and apoptotic markers at mRNA and protein levels were performed by reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence analysis, respectively. We demonstrated that cordycepin (6.25-25 µM) contributed to significant increases in expression of the salivary marker genes, alpha-amylase 1 (AMY1A) and aquaporin-5 (AQP5), and in amylase secretion without changes in cell viability. Under oxidative stress, HSG cells showed remarkable dysfunction. Cordycepin rescued the protective effects partially by decreasing ROS generation and restoring the expression of the salivary proteins, AMY and AQP5 via anti-oxidant and anti-apoptotic activity. In addition, the amount of amylase that was secreted from HSG cells cultured in cordycepin was increased. In conclusion, cordycepin demonstrated a protective effect on H2O2 -induced HSG cells by decreasing ROS generation and upregulating the salivary function markers, AMY1A and AQP5, at both the transcriptional and translational levels.

Fabrication of 3D calcium-alginate scaffolds for human glioblastoma modeling and anticancer drug response evaluation.

The three-dimensional (3D) cell culture model has been increasingly used to study cancer biology and screen for anticancer agents due to its close mimicry to in vivo tumor biopsies. In this study, 3D calcium(Ca)-alginate scaffolds were developed for human glioblastoma cell culture and an investigation of the responses to two anticancer agents, doxorubicin and cordycepin. Compared to the 2D monolayer culture, glioblastoma cells cultured on these 3D Ca-alginate scaffolds showed reduced cell proliferation, increased tumor spheroid formation, enhanced expression of cancer stem cell genes (CD133, SOX2, Nestin, and Musashi-1), and improved expression of differentiation potential-associated genes (GFAP and ß-tubulin III). Additionally, the vascularization potential of the 3D glioblastoma cells was increased, as indicated by a higher expression of tumor angiogenesis biomarker (VEGF) than in the cells in 2D culture. To highlight the application of Ca-alginate scaffolds, the 3D glioblastomas were treated with anticancer agents, including doxorubicin and cordycepin. The results demonstrated that the 3D glioblastomas presented a greater resistance to the tested anticancer agents than that of the cells in 2D culture. In summary, the 3D Ca-alginate scaffolds for glioblastoma cells that were developed in this study offer a promising platform for anticancer agent screening and the discovery of drug-resistant mechanisms of cancer.

Enrichment of cordycepin for cosmeceutical applications: culture systems and strategies.

Cordyceps spp. is the herbal medication initially used in China and has been reported as the unique resource of cordycepin. Cordycepin exhibits many health benefits, including anti-photoaging and anti-pigmentation; therefore, it potentially is a bioactive ingredient of cosmetic products. In order to enrich cordycepin content in Cordyceps, two artificial cultivation procedures, which are solid-state fermentation and liquid culture, were developed and optimized. The aim of this review is to illustrate cordycepin biosynthesis pathway in Cordyceps, and its bioactivity for cosmeceutical applications, as well as comparing the two different cultivation procedures. The basic model of artificial cultivation of Cordyceps is introduced; meanwhile, the potential application of modern biotechnology to the artificial cultivation is also discussed. This review should be of interest to the readers for the development of cordycepin bioproduction in order to be applied in cosmeceutical industry and some other uses.

Roles of autophagy in controlling stem cell identity: a perspective of self-renewal and differentiation.

Autophagy is crucial for the removal of dysfunctional organelles and protein aggregates and for maintaining stem cell homeostasis, which includes self-renewal, cell differentiation and somatic reprogramming. Loss of self-renewal capacity and pluripotency is a major obstacle to stem cell-based therapies. It has been reported that autophagy regulates stem cells under biological stimuli, starvation, hypoxia, generation of reactive oxygen species (ROS) and cellular senescence. On the one hand, autophagy is shown to play roles in self-renewal by co-function with the ubiquitin-proteasome system (UPS) to promote pluripotency-associated proteins (NANOG, OCT4 and SOX2) in human embryonic stem cells (hESCs). On the other hand, autophagy activity acts as cell reprogramming processes that play an important role for clearance fate determination and upregulates neural and cardiac differentiation. Deregulation of autophagy triggers protein disorders such as neurodegenerative cardiac/muscle diseases and cancer. Therefore, understanding of the roles of the autophagy in stem cell renewal and differentiation may benefit therapeutic development for a range of human diseases.

Inhibition of WNT signaling reduces differentiation and induces sensitivity to doxorubicin in human malignant neuroblastoma SH-SY5Y cells.

Neuroblastoma is one of the most common cancers in infancy, arising from the neuroblasts during embryonic development. This cancer is difficult to treat and resistance to chemotherapy is often found; therefore, clinical trials of novel therapeutic approaches, such as targeted-cancer signaling, could be an alternative for a better treatment. WNT signaling plays significant roles in the survival, proliferation, and differentiation of human neuroblastoma. In this report, WNT signaling of a malignant human neuroblastoma cell line, SH-SY5Y cells, was inhibited by XAV939, a specific inhibitor of the Tankyrase enzyme. XAV939 treatment led to the reduction of ß-catenin within the cells, confirming its inhibitory effect of WNT. The inhibition of WNT signaling by XAV939 did not affect cell morphology, survival, and proliferation; however, the differentiation and sensitivity to anticancer drugs of human neuroblastoma cells were altered. The treatment of XAV939 resulted in the downregulation of mature neuronal markers, including ß-tubulin III, PHOX2A, and PHOX2B, whereas neural progenitor markers (PAX6, TFAP2α, and SLUG) were upregulated. In addition, the combination of XAV939 significantly enhanced the sensitivity of SH-SY5Y and IMR-32 cells to doxorubicin in both 2D and 3D culture systems. Microarray gene expression profiling suggested numbers of candidate target genes of WNT inhibition by XAV939, in particular, p21, p53, ubiquitin C, ZBED8, MDM2, CASP3, and FZD1, and this explained the enhanced sensitivity of SH-SY5Y cells to doxorubicin. Altogether, these results proposed that the altered differentiation of human malignant neuroblastoma cells by inhibiting WNT signaling sensitized the cells to anticancer drugs. This approach could thus serve as an effective treatment option for aggressive brain malignancy.

Notch signaling regulates the differentiation of neural crest from human pluripotent stem cells.

Neural crest cells are specified at the border between the neural plate and the epiderm. They are capable of differentiating into various somatic cell types, including craniofacial and peripheral nerve tissues. Notch signaling plays important roles during neurogenesis; however, its function during human neural crest development is poorly understood. Here, we generated self-renewing premigratory neural-crest-like cells (pNCCs) from human pluripotent stem cells (hPSCs) and investigated the roles of Notch signaling during neural crest differentiation. pNCCs expressed various neural-crest-specifier genes, including SLUG (also known as SNAI2), SOX10 and TWIST1, and were able to differentiate into most neural crest derivatives. Blocking Notch signaling during the pNCC differentiation suppressed the expression of neural-crest-specifier genes. By contrast, ectopic expression of activated Notch1 intracellular domain (NICD1) augmented the expression of neural-crest-specifier genes, and NICD1 was found to bind to their promoter regions. Notch activity was also required for the maintenance of the premigratory neural crest state, and the suppression of Notch signaling led to the generation of neural-crest-derived neurons. Taken together, we provide a protocol for the generation of pNCCs and show that Notch signaling regulates the formation, migration and differentiation of neural crest from hPSCs.

Inhibition of FGF signaling accelerates neural crest cell differentiation of human pluripotent stem cells.

Neural crest (NC) is a transient population, arising during embryonic development and capable of differentiating into various somatic cells. The defects of neural crest development leads to neurocristopathy. Several signaling pathways were revealed their significance in NC cell specification. Fibroblast growth factor (FGF) is recognized as an important signaling during NC development, for instance Xenopus and avian; however, its contributions in human species are remained elusive. Here we used human pluripotent stem cells (hPSCs) to investigate the consequences of FGF inhibition during NC cell differentiation. The specific-FGF receptor inhibitor, SU5402, was used in this investigation. The inhibition of FGF did not found to affect the proliferation or death of hPSC-derived NC cells, but promoted hPSCs to commit NC cell fate. NC-specific genes, including PAX3, SLUG, and TWIST1, were highly upregulated, while hPSC genes, such as OCT4, and E-CAD, rapidly reduced upon FGF signaling blockage. Noteworthy, TFAP-2α, a marker of migratory NC cells, abundantly presented in SU5402-induced cells. This accelerated NC cell differentiation could be due to the activation of Notch signaling upon the blockage of ERK1/2 phosphorylation, since NICD was increased by SU5402. Altogether, this study proposed the contributions of FGF signaling in controlling human NC cell differentiation from hPSCs, the crosstalk between FGF and Notch, and might imply to the influences of FGF signaling in neurocristophatic diseases.

Neural crest cells: from developmental biology to clinical interventions.

Neural crest cells are multipotent cells, which are specified in embryonic ectoderm in the border of neural plate and epiderm during early development by interconnection of extrinsic stimuli and intrinsic factors. Neural crest cells are capable of differentiating into various somatic cell types, including melanocytes, craniofacial cartilage and bone, smooth muscle, and peripheral nervous cells, which supports their promise for cell therapy. In this work, we provide a comprehensive review of wide aspects of neural crest cells from their developmental biology to applicability in medical research. We provide a simplified model of neural crest cell development and highlight the key external stimuli and intrinsic regulators that determine the neural crest cell fate. Defects of neural crest cell development leading to several human disorders are also mentioned, with the emphasis of using human induced pluripotent stem cells to model neurocristopathic syndromes.

An anthocyanin-rich extract from Zea mays L. var. ceratina alleviates neuronal cell death caused by hydrogen peroxide-induced cytotoxicity in SH-SY5Y cells.

The incidence of dementia is rising, with neuronal cell death from oxidative stress and apoptosis recognized as a significant contributor to its development. However, effective strategies to combat this condition are lacking, necessitating further investigation. This study aimed to assess the potential of an anthocyanin-rich extract from Zea mays L. var. ceratina (AZC) in alleviating neuronal cell death.Neurotoxicity was induced in SH-SY5Y cells using hydrogen peroxide (H2O2) at a concentration of 200 µM. Cells were pretreated with varying doses (31.25 and 62.5 µg/mL) of AZC. Cell viability was assessed using the MTT assay, and molecular mechanisms including reactive oxygen species (ROS) levels, antioxidant enzyme activities (catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px)), malondialdehyde (MDA) levels for oxidative stress, and the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), cAMP response element-binding protein (CREB), and apoptotic factors (B-cell lymphoma 2 (Bcl-2), caspase 3) were explored.Results showed that AZC significantly improved cell viability, reduced ROS production and MDA levels, and downregulated caspase 3 expression. It enhanced CAT, SOD, and GSH-Px activities, activated ERK1/2 and CREB, and upregulated Bcl-2 expression. These findings support the neuroprotective effects of AZC, suggesting it activates ERK1/2, leading to CREB activation and subsequent upregulation of Bcl-2 expression while suppressing caspase 3. AZC may mitigate neuronal cell death by reducing ROS levels through enhanced scavenging enzyme activities.In conclusion, this study underscores the potential of AZC as a neuroprotective agent against neuronal cell death. However, further investigations including toxicity assessments, in vivo studies, and clinical trials are necessary to validate its benefits in neuroprotection.

Effect of ultrasound and thermal pretreatments on antioxidant activity of egg white hydrolysate.

The use of ultrasonic (US) treatment of egg white prior to enzymatic hydrolysis to produce hydrolysate with antioxidant activity was investigated. The state of egg white (raw vs. cooked form) along with two levels of Alcalase (1% and 10% (w/w) protein) was applied. Hydrolysis and antioxidant activity of hydrolysate increased by US pretreatment at intensity of 41.53 W/cm2 . The hydrolysate prepared from US treatment on raw egg white hydrolyzed by 1% Alcalase (US-R1%) showed the lowest degree of hydrolysis (DH); however, its 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging and ferric reducing antioxidant power activities were the highest. In contrast, the highest cytoprotective effect and intracellular reactive oxygen species scavenging activity were more notable in the hydrolysate prepared from US treatment of boiled egg white hydrolyzed by 10% Alcalase (US-B10%), which also exhibited the highest DH and metal chelation ability. The hydrolysate possessing cellular antioxidant activity (CAA) showed the highest proportion of small molecular weight peptides (<200 Da). Fourier-transform infrared spectroscopy revealed an increase of N- and C-terminal ends at 1500 and 1400 cm-1 , respectively, in concomitant with a decrease of amide I. Principal component analysis showed clear differentiation of spectra from different levels of enzyme according to their DH, C-terminal ends, and antioxidant activity. Our findings suggested that cooked egg white followed by US pretreatment was beneficial to produce hydrolysate containing high CAA.

Glycation of tilapia protein hydrolysate decreases cellular antioxidant activity upon in vitro gastrointestinal digestion.

Changes in structural characteristics and antioxidant activity of tilapia hydrolysate glycated with glucose, fructose, or xylose at 90 °C for 12 h, and following in vitro gastrointestinal (GI) digestion were investigated. Fourier-transformed infrared (FTIR) band between 1,800 and 1,400 cm-1 confirmed the structural modifications of hydrolysate under glycations. Glycation drastically increased ATBS·+ and ONOO- scavenging activities (p < 0.05) as well as ferric-reducing antioxidant power (FRAP). Xylose was the most effective sugar for glycation, yielding the highest chemical antioxidant activities (p < 0.05). However, glycated hydrolysates exhibited lower cellular antioxidant activity (CAA) on HepG2 cell when compared to hydrolysates. The extensive glycation of hydrolysates resulted in lower GI digestibility as confirmed by the FTIR spectra of C[bond, double bond]O, C-N, N-H, C-C, C-O, and C-H stretching vibrations. Glycation of tilapia hydrolysates only improved chemical antioxidant activities, but alleviated CAA, especially upon simulated GI digestion.