Past, Present and Future of the Section "Molecular Toxicology".

'Forever' chemicals that unintendedly in the long run pollute the environment, climate change, COVID; life continuously faces all sorts of unforeseen challenges that are an inevitable side product of 'progress' [...].

Unraveling the Antioxidant Activity of 2R,3R-dihydroquercetin.

It has been reported that in an oxidative environment, the flavonoid 2R,3R-dihydroquercetin (2R,3R-DHQ) oxidizes into a product that rearranges to form quercetin. As quercetin is a very potent antioxidant, much better than 2R,3R-DHQ, this would be an intriguing form of targeting the antioxidant quercetin. The aim of the present study is to further elaborate on this targeting. We can confirm the previous observation that 2R,3R-DHQ is oxidized by horseradish peroxidase (HRP), with H2O2 as the oxidant. However, HPLC analysis revealed that no quercetin was formed, but instead an unstable oxidation product. The inclusion of glutathione (GSH) during the oxidation process resulted in the formation of a 2R,3R-DHQ-GSH adduct, as was identified using HPLC with IT-TOF/MS detection. GSH adducts appeared on the B-ring of the 2R,3R-DHQ quinone, indicating that during oxidation, the B-ring is oxidized from a catechol to form a quinone group. Ascorbate could reduce the quinone back to 2R,3R-DHQ. No 2S,3R-DHQ was detected after the reduction by ascorbate, indicating that a possible epimerization of 2R,3R-DHQ quinone to 2S,3R-DHQ quinone does not occur. The fact that no epimerization of the oxidized product of 2R,3R-DHQ is observed, and that GSH adducts the oxidized product of 2R,3R-DHQ on the B-ring, led us to conclude that the redox-modulating activity of 2R,3R-DHQ quinone resides in its B-ring. This could be confirmed by chemical calculation. Apparently, the administration of 2R,3R-DHQ in an oxidative environment does not result in 'biotargeting' quercetin.

Flavonoids Seen through the Energy Perspective.

In all life forms, opposing forces provide the energy that flows through networks in an organism, which fuels life. In this concept, health is the ability of an organism to maintain the balance between these opposing forces, which creates resilience, and a deranged flow of energy is the basis for diseases. Treatment should focus on adjusting the deranged flow of energy, e.g., by the redox modulating activity of antioxidants. A major group of antioxidants is formed by flavonoids, a group of polyphenolic compounds abundantly present in our diet. The objective here is to review how the redox modulation by flavonoids fits in the various concepts on the mode of action of bioactive compounds, so we can 'see' where there is overlap and where the missing links are. Based on this fundament, we should choose our research path aiming to 'understand' the redox modulating profile of specific flavonoids, so we can ultimately rationally apply the redox modulating power of flavonoids to improve our health.

Delocalization of the Unpaired Electron in the Quercetin Radical: Comparison of Experimental ESR Data with DFT Calculations.

In the antioxidant activity of quercetin (Q), stabilization of the energy in the quercetin radical (Q•) by delocalization of the unpaired electron (UE) in Q• is pivotal. The aim of this study is to further examine the delocalization of the UE in Q•, and to elucidate the importance of the functional groups of Q for the stabilization of the UE by combining experimentally obtained spin resonance spectroscopy (ESR) measurements with theoretical density functional theory (DFT) calculations. The ESR spectrum and DFT calculation of Q• and structurally related radicals both suggest that the UE of Q• is mostly delocalized in the B ring and partly on the AC ring. The negatively charged oxygen groups in the B ring (3' and 4') of Q• have an electron-donating effect that attract and stabilize the UE in the B ring. Radicals structurally related to Q• indicate that the negatively charged oxygen at 4' has more of an effect on concentrating the UE in ring B than the negatively charged oxygen at 3'. The DFT calculation showed that an OH group at the 3-position of the AC ring is essential for concentrating the radical on the C2-C3 double bond. All these effects help to explain how the high energy of the UE is captured and a stable Q• is generated, which is pivotal in the antioxidant activity of Q.

The Flow of the Redox Energy in Quercetin during Its Antioxidant Activity in Water.

Most studies on the antioxidant activity of flavonoids like Quercetin (Q) do not consider that it comprises a series of sequential reactions. Therefore, the present study examines how the redox energy flows through the molecule during Q's antioxidant activity, by combining experimental data with quantum calculations. It appears that several main pathways are possible. Pivotal are subsequently: deprotonation of the 7-OH group; intramolecular hydrogen transfer from the 3-OH group to the 4-Oxygen atom; electron transfer leading to two conformers of the Q radical; deprotonation of the OH groups in the B-ring, leading to three different deprotonated Q radicals; and finally electron transfer of each deprotonated Q radical to form the corresponding quercetin quinones. The quinone in which the carbonyl groups are the most separated has the lowest energy content, and is the most abundant quinone. The pathways are also intertwined. The calculations show that Q can pick up redox energy at various sites of the molecule which explains Q's ability to scavenge all sorts of reactive oxidizing species. In the described pathways, Q picked up, e.g., two hydroxyl radicals, which can be processed and softened by forming quercetin quinone.

Connecting West and East.

Despite their similarities, Western medicine and Eastern medicine are very different because they are built on different fundamentals. The general idea has arisen that we will benefit by connecting Western and Eastern medicine. First, both the merits as well as the limitations of both types of medicine are discussed. It was concluded that to create a bridge, we should focus on similarities that inspire the further unravelling of the molecular mechanism of the mode of action and toxicity of Traditional Chinese Medicine. It is suggested that the energy perspective provides a basis to integrate Eastern and Western medicine.

Rutin protects against H2O2-triggered impaired relaxation of placental arterioles and induces Nrf2-mediated adaptation in Human Umbilical Vein Endothelial Cells exposed to oxidative stress.

BACKGROUND: Rutin intake is associated with a reduced risk of cardiovascular disease (CVD). The exact mechanism by which rutin can protect against CVD development is still enigmatic. Since, rutin is a compound with a relatively short half-life, the direct antioxidant effect of rutin cannot explain the long-lasting effect on human health. We hypothesized that rutin next to its direct antioxidant effect that improves endothelial function, may also induce an adaptive response in endogenous antioxidant systems. METHODS AND RESULTS: In Human Umbilical Vein Endothelial Cells (HUVECs), the direct antioxidant effect was confirmed. During scavenging of Reactive Oxygen Species (ROS), rutin is oxidized into a quinone derivative. HUVECs pretreated with rutin quinone became better protected against a second challenge with oxidative stress 3h later. LC-MS/MS analysis indicated that rutin quinone targets cysteine 151 of Keap1. Moreover, we found that the quinone is an inhibitor of the selenoprotein thioredoxin reductase 1. These properties correlated with an activation of Nrf2 and upregulation of Glutamate Cysteine Ligase, the rate-limiting enzyme of glutathione synthesis, while NF-κB and HIF activation became blunted by rutin treatment. Furthermore, rutin was found to prevent hydrogen peroxide from impairing relaxation of human chorionic plate placental vessels, which may help to protect endothelial function. CONCLUSION AND SIGNIFICANCE: Rutin functions as an antioxidant and is oxidized into a quinone that upregulates the Nrf2-mediated endogenous antioxidant response. This mechanism suggests that rutin selectively exerts its protective effects in regions with increased oxidative stress, and explains how rutin reduces the risk of developing CVD. GENERAL SIGNIFICANCE: The newly found mechanism behind the long-term protection of rutin against cardiovascular disease, the selective upregulation of endogenous antioxidant systems, contributes to the further understanding why rutin can reduce the risk on developing cardiovascular disease.

The potential of flavonoids in the treatment of non-alcoholic fatty liver disease.

The contemporary pathophysiological model of non-alcoholic fatty liver disease (NAFLD) comprises multiple parallel pathways with a dynamic cross talk that cumulate in steatosis and inflammation, and ultimately fibrosis, cirrhosis, liver failure, and hepatocellular carcinoma. So far, no pharmacological treatment has been approved. A major impediment of drugs, in general, is that they are intended to act on one single target in the pathology of a disease. However, the multitude of pathways involved in the pathogenesis of NAFLD underpins the need for treatments that address these various pathways. Interestingly, flavonoids have been found to have positive effects on lipid metabolism, insulin resistance, inflammation, and oxidative stress, the most important pathophysiological pathways in NAFLD. This puts flavonoids in the spotlight for the treatment of NAFLD and prompted us to review the existing evidence for the use of these food-derived compounds in the treatment of NAFLD.

The Screening of Anticholinergic Accumulation by Traditional Chinese Medicine.

Many Western drugs can give rise to serious side effects due to their ability to bind to acetylcholine receptors in the brain. This aggravates when they are combined, which is known as anticholinergic accumulation (AA). Some bioactives in Traditional Chinese Medicine (TCM) are known to block acetylcholine receptors and thus potentially cause AA. The AA of TCM was screened by quantifying the displacement of [³H] pirenzepine on acetylcholine receptors in a rat brain homogenate. We used a new unit to express AA, namely the Total Atropine Equivalents (TOAT). The TOAT of various herbs used in TCM was very diverse and even negative for some herbs. This is indicative for the broadness of the pallet of ingredients used in TCM. Three TCM formulas were screened for AA: Ma Huang Decotion (MHD), Antiasthma Simplified Herbal Medicine intervention (ASHMI), and Yu Ping Feng San (YPFS). The TOAT of ASHMI was indicative for an additive effect of herbs used in it. Nevertheless, it can be calculated that one dose of ASHMI is probably too low to cause AA. The TOAT of YPFS was practically zero. This points to a protective interaction of AA. Remarkably, MHD gave a negative TOAT, indicating that the binding to the acetylcholine receptors was increased, which also circumvents AA. In conclusion, our results indicate that TCM is not prone to give AA and support that there is an intricate interaction between the various bioactives in TCM to cure diseases with minimal side effects.

Chemical Reactivity Window Determines Prodrug Efficiency toward Glutathione Transferase Overexpressing Cancer Cells.

Glutathione transferases (GSTs) are often overexpressed in tumors and frequently correlated to bad prognosis and resistance against a number of different anticancer drugs. To selectively target these cells and to overcome this resistance we previously have developed prodrugs that are derivatives of existing anticancer drugs (e.g., doxorubicin) incorporating a sulfonamide moiety. When cleaved by GSTs, the prodrug releases the cytostatic moiety predominantly in GST overexpressing cells, thus sparing normal cells with moderate enzyme levels. By modifying the sulfonamide it is possible to control the rate of drug release and specifically target different GSTs. Here we show that the newly synthesized compounds, 4-acetyl-2-nitro-benzenesulfonyl etoposide (ANS-etoposide) and 4-acetyl-2-nitro-benzenesulfonyl doxorubicin (ANS-DOX), function as prodrugs for GSTA1 and MGST1 overexpressing cell lines. ANS-DOX, in particular, showed a desirable cytotoxic profile by inducing toxicity and DNA damage in a GST-dependent manner compared to control cells. Its moderate conversion of 500 nmol/min/mg, as catalyzed by GSTA1, seems hereby essential since the more reactive 2,4-dinitrobenzenesulfonyl doxorubicin (DNS-DOX) (14000 nmol/min/mg) did not display a preference for GSTA1 overexpressing cells. DNS-DOX, however, effectively killed GSTP1 (20 nmol/min/mg) and MGST1 (450 nmol/min/mg) overexpressing cells as did the less reactive 4-mononitrobenzenesulfonyl doxorubicin (MNS-DOX) in a MGST1-dependent manner (1.5 nmol/min/mg) as shown previously. Furthermore, we show that the mechanism of these prodrugs involves a reduction in GSH levels as well as inhibition of the redox regulatory enzyme thioredoxin reductase 1 (TrxR1) by virtue of their electrophilic sulfonamide moiety. TrxR1 is upregulated in many tumors and associated with resistance to chemotherapy and poor patient prognosis. Additionally, the prodrugs potentially acted as a general shuttle system for DOX, by overcoming resistance mechanisms in cells. Here we propose that GST-dependent prodrugs require a conversion rate "window" in order to selectively target GST overexpressing cells, while limiting their effects on normal cells. Prodrugs are furthermore a suitable system to specifically target GSTs and to overcome various drug resistance mechanisms that apply to the parental drug.

Time in Redox Adaptation Processes: From Evolution to Hormesis.

Life on Earth has to adapt to the ever changing environment. For example, due to introduction of oxygen in the atmosphere, an antioxidant network evolved to cope with the exposure to oxygen. The adaptive mechanisms of the antioxidant network, specifically the glutathione (GSH) system, are reviewed with a special focus on the time. The quickest adaptive response to oxidative stress is direct enzyme modification, increasing the GSH levels or activating the GSH-dependent protective enzymes. After several hours, a hormetic response is seen at the transcriptional level by up-regulating Nrf2-mediated expression of enzymes involved in GSH synthesis. In the long run, adaptations occur at the epigenetic and genomic level; for example, the ability to synthesize GSH by phototrophic bacteria. Apparently, in an adaptive hormetic response not only the dose or the compound, but also time, should be considered. This is essential for targeted interventions aimed to prevent diseases by successfully coping with changes in the environment e.g., oxidative stress.

Food-Derived Bioactives Can Protect the Anti-Inflammatory Activity of Cortisol with Antioxidant-Dependent and -Independent Mechanisms.

In chronic inflammatory diseases the anti-inflammatory effect of glucocorticoids (GCs) is often decreased, leading to GC resistance. Inflammation is related with increased levels of reactive oxygen species (ROS), leading to oxidative stress which is thought to contribute to the development of GC resistance. Plant-derived compounds such as flavonoids are known for their ability to protect against ROS. In this exploratory study we screened a broad range of food-derived bioactives for their antioxidant and anti-inflammatory effects in order to investigate whether their antioxidant effects are associated with the ability to preserve the anti-inflammatory effects of cortisol. The anti-inflammatory potency of the tested compounds was assessed by measuring the oxidative stress-induced GC resistance in human macrophage-like cells. Cells were pre-treated with H2O2 (800 µM) with and without bioactives and then exposed to lipopolysaccharides (LPS) (10 ng/mL) and cortisol (100 nM). The level of inflammation was deducted from the concentration of interleukin-8 (IL-8) in the medium. Intracellular oxidative stress was measured using the fluorescent probe 2',7'-dichlorofluorescein (DCFH). We found that most of the dietary bioactives display antioxidant and anti-inflammatory action through the protection of the cortisol response. All compounds, except for quercetin, revealing antioxidant activity also protect the cortisol response. This indicates that the antioxidant activity of compounds plays an important role in the protection of the GC response. However, next to the antioxidant activity of the bioactives, other mechanisms also seem to be involved in this protective, anti-inflammatory effect.

The flavonoid monoHER promotes the adaption to oxidative stress during the onset of NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease. An evidence-based pharmacological treatment for NAFLD is still lacking, but flavonoids have shown therapeutic potential. The present study was designed to investigate the effect of the flavonoid monoHER on the onset of NAFLD in Ldlr(-/-) mice on a high-fat and high-cholesterol diet. The focus was put on the effect on oxidative stress as well as the adaptive response. Wild type mice served as a control and the effect of monoHER was compared to that of a placebo. In the Ldlr(-/-) group, monoHER provided only a mild protection against oxidative stress. In the placebo Ldlr(-/-) group an adaptive response elicited by the NRF2 antioxidant defense system was observed, evidenced by a higher HO-1 and Gpx3 gene expression, as well as an increased redox status, evidenced by the higher GSH/GSSG ratio. In the monoHER treated Ldlr(-/-) group both the adaptive response as well as the increase in redox status tended to be higher, although this did not reach significance on a group level. Unexpectedly, a strong within animal relationship was found that links a high adaptive response to a low redox status in the monoHER Ldlr(-/-) group. This correlation was absent in the placebo and wild type group. The concept that emerges is that a thiol-reactive oxidation product of monoHER, formed during oxidative stress, selectively induces the NRF2 pathway and enforces the endogenous antioxidant shield, to provide protection against NAFLD.

Adaptation to acrolein through upregulating the protection by glutathione in human bronchial epithelial cells: the materialization of the hormesis concept.

Acrolein is a thiol reactive compound present in cigarette smoke and plays a pivotal role in the deleterious effects of smoking. Acrolein causes toxicity in human bronchial epithelial cells in a dose dependent manner. GSH forms the first line of defense against acrolein-induced toxicity. At high doses of acrolein (⩾10 µM) the capacity of the cellular protection by GSH is overwhelmed and GSH is not able to quench all the acrolein, resulting in cytotoxicity. At a relatively low dose of acrolein (3 µM), no cytotoxicity is observed due to protection by GSH. Moreover we found that exposure to a low dose of acrolein protects cells against the toxic effect of a second higher dose of acrolein. The adaptation to acrolein is induced via Nrf2 mediated gene expression of γ-glutamylcysteine synthetase leading to elevated GSH levels. This upregulation of the protection by GSH demonstrates a hormetic response to acrolein. Hormesis is an adaptive or compensatory response induced by a relatively subtle challenge of homeostasis by a toxic compound. Insight into the mechanism of hormesis is mandatory for a more accurate societal regulation of toxic compounds.

The cocoa flavanol (-)-epicatechin protects the cortisol response.

Various health benefits of the cocoa flavanol (-)-epicatechin (EC) have been attributed to its antioxidant and anti-inflammatory potency. In the present study we investigated whether EC is able to prevent deterioration of the anti-inflammatory effect of the glucocorticoid (GC) cortisol in the presence of oxidative stress. It was found that cortisol reduces inflammation in differentiated monocytes. Oxidative stress extinguishes the anti-inflammatory effect of cortisol, leading to cortisol resistance. EC reduces intracellular oxidative stress as well as the development of cortisol resistance. This further deciphers the enigmatic mechanism of EC by which it exerts its anti-inflammatory and antioxidant action. The observed effect of the cocoa flavanol EC will especially be of relevance in pathophysiological conditions with increased oxidative stress and consequential GC resistance and provides a fundament for the rational use of dietary antioxidants.

The minor structural difference between the antioxidants quercetin and 4'O-methylquercetin has a major impact on their selective thiol toxicity.

Antioxidants act as intermediates by picking up the high unselective reactivity of radicals and transferring it to other molecules. In this process the reactivity is reduced and becomes selective. This channeling of the reactivity can cause selective toxicity. The antioxidant quercetin is known to channel the reactivity towards thiol groups. The present study compares the thiol reactivity of quercetin with that of 4'O-methylquercetin (tamarixetin) towards creatine kinase (CK), a vital protein that contains a critical thiol moiety. Our results showed that oxidized quercetin and oxidized tamarixetin both adduct CK, which then loses its enzymatic function. Ascorbate, an important representative of the antioxidant network, is able to prevent adduction to and thus the inhibition of the enzyme by tamarixetin but not by quercetin. Apparently, tamarixetin is less thiol toxic than quercetin, because--rather than adduction to CK--tamarixetin quinone prefers to pass reactivity to the antioxidant network, i.e., to ascorbate. The findings exemplify that radical scavenging flavonoids pick up the reactivity of radicals and act as a pivot in directing the way the reactivity is channeled. A mere minor structural difference of only one methyl moiety between quercetin and tamarixetin appears to have a high impact on the selective, thiol toxicity.

Neutrophils augment LPS-mediated pro-inflammatory signaling in human lung epithelial cells.

BACKGROUND: The role of polymorphonuclear neutrophils in pulmonary host defense is well recognized. The influence of a pre-existing inflammation driven by neutrophils (neutrophilic inflammation) on the airway epithelial response toward pro-inflammatory exogenous triggers, however, is still poorly addressed. Therefore, the aim of the present study is to investigate the effect of neutrophils on lipopolysaccharide (LPS)-induced pro-inflammatory signaling in lung epithelial cells. Additionally, underlying signaling pathways are examined. METHODS: Human bronchial epithelial cells (BEAS-2B) were co-incubated with human peripheral blood neutrophils or bone-marrow derived neutrophils from either C57BL/6J wild type or nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase deficient (p47(phox-/-)) mice. Upon stimulation with LPS, interleukin (IL)-8 production and reactive oxygen species (ROS) generation were measured. Additionally, activation of the extracellular signal-regulated kinases (ERK) 1/2 and nuclear factor (NF)-κB signaling pathways was analyzed. RESULTS: Our studies show that the presence of neutrophils synergistically increases LPS-induced IL-8 and ROS production by BEAS-2B cells without inducing cytotoxicity. The observed IL-8 response to endotoxin increases in proportion to time, LPS-concentration and the number of neutrophils present. Moreover, this synergistic IL-8 production strongly correlated with the chemotactic properties of the co-incubations and significantly depended on a functional neutrophilic NADPH oxidase. The presence of neutrophils also augments LPS-induced phosphorylation of ERK1/2 and IκBα as well as NF-κB RelA DNA binding activity in BEAS-2B cells. CONCLUSIONS: Our results indicate that the pro-inflammatory effects of LPS toward lung epithelial cells are amplified during a pre-existing neutrophilic inflammation. These findings support the concept that patients suffering from pulmonary neutrophilic inflammation are more susceptible toward exogenous pro-inflammatory triggers.

Tubular epithelial injury and inflammation after ischemia and reperfusion in human kidney transplantation.

OBJECTIVE: To provide an integrated insight into the kinetics of tubular injury, inflammation, and oxidative stress after human kidney transplantation. BACKGROUND: Tissue injury due to ischemia and reperfusion is an inevitable consequence of kidney transplantation. Tubular epithelial injury, inflammation, and oxidative stress play major roles in the pathophysiology of acute kidney injury in small animals, but it remains to be established whether this paradigm holds true for human kidney transplantation. METHODS: Markers of tubular injury, inflammation, and oxidative stress were compared between recipients of kidneys from donors after cardiac death (DCD; N = 8) with prolonged ischemia and recipients of living donor kidneys with minimal ischemia (N = 8). RESULTS: In the early postoperative period, creatinine clearance and tubular sodium reabsorption were profoundly reduced in DCD kidneys, coinciding with significantly increased urinary concentrations of tubular injury markers (neutrophil gelatinase-associated lipocalin, N-acetyl-ß--glucosaminidase, and cystatin C) and an 18-fold increase in renal production of cytokeratin-18, indicating extensive necrotic cell death. Tubular injury in DCD kidneys was followed by greater systemic inflammatory activity and oxidative stress in the postoperative period (measured with 17-plex cytokine arrays and as plasma F2-isoprostanes, respectively). In contrast, no evidence of oxidative damage to either of the 2 kidney types was found in the early reperfusion period. CONCLUSIONS: These findings establish the relevance of observations in animal models for human kidney transplantation and form the basis for development of novel therapies to improve early graft function and expand the use of donor kidneys with prolonged ischemia.

Identification of the metabolites of the antioxidant flavonoid 7-mono-O-(ß-hydroxyethyl)-rutoside in mice.

The clinical use of the anticancer drug doxorubicin is limited by severe cardiotoxicity. In mice, the semisynthetic antioxidant flavonoid 7-mono-O-(ß-hydroxyethyl)-rutoside (monoHER) has been successfully used as a protector against doxorubicin-induced cardiotoxicity. However, most monoHER has already been cleared from the body at the time that doxorubicin concentrations are still high. This result suggests that not only the parent compound monoHER itself but also monoHER metabolites could be responsible for the observed cardioprotective effects in mice. Therefore, in the present study, we investigated the metabolism of monoHER in mice. Mice were administered 500 mg/kg monoHER intraperitoneally. At different time points after monoHER administration, bile was collected and analyzed for the presence of monoHER metabolites. The formed metabolites were identified by liquid chromatography-diode array detection-time of flight-mass spectrometry. Thirteen different metabolites were identified. The observed routes of monoHER metabolism are methylation, glucuronidation, oxidation of its hydroxyethyl group, GSH conjugation, and hydrolysis of its disaccharide. In line with other flavonoids, methylated monoHER and the monoHER glucosides are expected to have relatively high cellular uptake and low clearance from the body. Therefore, these metabolites might contribute to the observed protection of monoHER against doxorubicin-induced cardiotoxicity.

Bioprocessing of wheat bran in whole wheat bread increases the bioavailability of phenolic acids in men and exerts antiinflammatory effects ex vivo.

Whole grain consumption has been linked to a lower risk of metabolic syndrome, which is normally associated with a low-grade chronic inflammation. The benefits of whole grain are in part related to the inclusion of the bran, rich in phenolic acids and fiber. However, the phenols are poorly bioaccessible from the cereal matrix. The aim of the present study was to investigate the effect of bioprocessing of the bran in whole wheat bread on the bioavailability of phenolic acids, the postprandial plasma antioxidant capacity, and ex vivo antiinflammatory properties. After consumption of a low phenolic acid diet for 3 d and overnight fasting, 8 healthy men consumed 300 g of whole wheat bread containing native bran (control bread) or bioprocessed bran (bioprocessed bread) in a cross-over design. Urine and blood samples were collected for 24 h to analyze the phenolic acids and metabolites. Trolox equivalent antioxidant capacity was measured in plasma. Cytokines were measured in blood after ex vivo stimulation with LPS. The bioavailabilities of ferulic acid, vanillic acid, sinapic acid, and 3,4-dimethoxybenzoic acid from the bioprocessed bread were 2- to 3-fold those from the control bread. Phenylpropionic acid and 3-hydroxyphenylpropionic acid were the main colonic metabolites of the nonbioaccessible phenols. The ratios of pro-:antiinflammatory cytokines were significantly lower in LPS-stimulated blood after the consumption of the bioprocessed bread. In conclusion, bioprocessing can remarkably increase the bioavailability of phenolic acids and their circulating metabolites, compounds which have immunomodulatory effects ex vivo.