Functional properties of anti-inflammatory substances from quercetin-treated Bifidobacterium adolescentis.

The genus Bifidobacterium is well known to have beneficial health effects. We discovered that quercetin and related polyphenols enhanced the secretion of anti-inflammatory substances by Bifidobacterium adolescentis. This study investigated characteristics of the anti-inflammatory substances secreted by B. adolescentis. The culture supernatant of B. adolescentis with quercetin reduced the levels of inflammatory mediators in activated macrophages. Spontaneous quercetin degradant failed to increase anti-inflammatory activity, while the enhancement of anti-inflammatory activity by quercetin was sustained after washout of quercetin. Physicochemical treatment of the culture supernatant indicated that its bioactive substances may be heat-stable, non-phenolic, and acidic biomolecules with molecular weights less than 3 kDa. Acetate and lactate have little or no effect on nitric oxide production. Taken together, the anti-inflammatory substances secreted by B. adolescentis may be small molecules but not short chain fatty acids. In agreement with these findings, stearic acid was tentatively identified as a bioactive candidate compound.

Effects of phytochemicals on in vitro anti-inflammatory activity of Bifidobacterium adolescentis.

Probiotics have been shown to improve the condition of not only the human gastrointestinal tract but also the entire body. We found that quercetin enhances the anti-inflammatory activity of Bifidobacterium adolescentis, which is abundant in human intestines. Here, we assessed whether certain phytochemicals could enhance the anti-inflammatory activity of B. adolescentis. Bifidobacteria were anaerobically cultured with phytochemicals for 3 h, and the anti-inflammatory activity of the supernatants was estimated by testing their ability to inhibit nitric oxide (NO) production by lipopolysaccharide-stimulated RAW264 macrophages. Of the 55 phytochemicals tested, phloretin, (+)-taxifolin, and (-)-epigallocatechin gallate as well as quercetin-3-O-glucoside and quercetin-4'-O-glucoside were similar to quercetin in promoting NO suppression by B. adolescentis. In addition, the phytochemicals excluding quercetin increased the concentrations of lactic and acetic acids in the co-culture supernatants. These results suggest that some phytochemicals may activate the anti-inflammatory function of B. adolescentis.

Suppressive effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient mice.

Previous studies in humans have shown that the cacao polyphenols, (-)-epicatechin and its oligomers, prevent in vitro and ex vivo low-density lipoprotein oxidation mediated by free radical generators and metal ions and also reduce plasma LDL-cholesterol levels. The aim of this study was to examine the effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice. Mice aged 8 weeks (n = 90) were randomized into three groups, and fed either normal mouse chow (controls) or chow supplemented with 0.25 or 0.40 % cacao polyphenols for 16 weeks. The mean plaque area in cross-sections of the brachiocephalic trunk was measured and found to be lower in the 0.25 % cacao polyphenol group than in the control group (p < 0.05). Pathological observations showed that accumulation of cholesterol crystals in the plaque area was greater in the control group compared with the 0.40 % cacao polyphenol group (p < 0.05). Immunochemical staining in the 0.25 and 0.40 % groups showed that expression of the cell adhesion molecules (VCAM-1 and ICAM-1) and production of oxidative stress markers (4-hydroxynonenal, hexanoyl-lysine, and dityrosine) were reduced in cross-sections of the brachiocephalic trunk. These results suggest that cacao polyphenols inhibit the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice by reducing oxidative stress and inflammatory responses.

Cacao Procyanidins-Induced Lifespan Extension in Caenorhabditis elegans in a Nervous System and CaMKII-Dependent Manner.

Procyanidins are gaining attention due to their potential health benefits. We found that cacao liquor procyanidin (CLPr) from Theobroma cacao seeds increased the lifespan of Caenorhabditis elegans, a representative model organism for aging studies. The genetic dependence of the lifespan-extending effect of CLPr was consistent with that of blueberry procyanidin, which is dependent on unc-43, osr-1, sek-1, and mev-1, but not on daf-16, sir-2.1, or skn-1. The lifespan-extending effect of CLPr was inhibited by neuron-specific RNA interference (RNAi) targeting unc-43 and pmk-1, and in worms with loss-of-function mutations in the odr-3, odr-1, or tax-4 genes, which are essential in sensory neurons, including AWC neurons. It was also inhibited in worms in which AWC neurons or AIB interneurons had been eliminated, and in worms with loss-of-function mutations in eat-4 or glr-1, which are responsible for glutamatergic synaptic transmission. These results suggest that the lifespan-extending effect of CLPr is dependent on the nervous system. In addition, it also requires unc-43 and pmk-1 expression in nonneuronal cells, as demonstrated by the experiments with RNAi in wild-type worms, the neuronal cells of which are not affected by systemic RNAi. The osr-1 gene is expressed in hypodermal and intestinal cells and regulates the response to osmotic stress along with unc-43/calcium/calmodulin-dependent protein kinase II and the p38 mitogen-activated protein kinase pathway. Consistent with this, CLPr improved osmotic stress tolerance in an unc-43- and pmk-1-dependent manner, and it was also dependent on AWC neurons. The lifespan-extending and osmotic-tolerance-improving activities were attributed to procyanidins with a tetrameric or higher-order oligomeric structure.

The effects of dark chocolate on cognitive performance during cognitively demanding tasks: A randomized, single-blinded, crossover, dose-comparison study.

Dark chocolate, rich in polyphenols, increases cerebral blood flow and improves cognitive function. This study aimed to determine whether the consumption of chocolate with a high concentration of polyphenols helps to maintain cognitive performance during cognitively demanding tasks. In this randomized, single-blinded, crossover, dose-comparison study, 18 middle-aged adults consumed two types of chocolate (25 g each), one with a high concentration (635.0 mg) and the other with a low concentration (211.7 mg) of cacao polyphenols, and performed a cognitive task requiring response inhibition and selective attention over two time periods (15-30 min and 40-55 min after consumption, respectively). Autonomic nerve function and subjective feelings, such as fatigue and concentration, were measured before food intake and after the second task to assess the participant's state. The results showed that the average reaction time between the first and second sessions was not significantly different for either high- or low-concentration chocolate consumption. However, the percentage of correct responses was similar in the first (96.7 %) and second (96.8 %) sessions for high-concentration chocolate consumption and significantly lower for low-concentration chocolate consumption in the second (96.4 %) session than in the first session (97.3 %). Autonomic nerve function showed a significant increase in sympathetic nerve activity after the second task with high-concentration chocolate consumption, while subjective feelings showed an increase in mental fatigue for both chocolate types but a significant decrease in concentration only after the second task with low-concentration chocolate consumption. These findings suggest that dark chocolate consumption contributes to the maintenance of performance and concentration in continuous and demanding cognitive tasks.

Cinnamtannin A2, a tetrameric procyanidin, increases GLP-1 and insulin secretion in mice.

Procyanidins are oligomers and polymers of flavan-3-ols consisting of (-)-epicatechin subunits. In this study, we isolated and purified dimeric, trimeric and tetrameric procyanidins from cacao liquor and investigated their influence on the "incretin effect" as compared to the monomer, (-)-epicatechin in mice. Cinnamtannin A2 specifically increased the glucagon-like peptide-1 (GLP-1) and insulin secretion levels in the plasma after 60 min administration. As evidence of the action of insulin, activation of insulin receptor and insulin receptor substrate-1 was observed in the soleus muscle. These results indicate that the intake of cinnamtannin A2 may improve hyperglycemia through an incretin-like effect, accompanied by activation of the insulin-signaling pathway.

Effect of Flavanol-Rich Cacao Extract on the Profile of Mood State in Healthy Middle-Aged Japanese Women: A Randomized, Double-Blind, Placebo-Controlled Pilot Study.

To investigate the effects of flavanol-rich cacao extract on healthy middle-aged women's fatigue and mood conditions, we conducted a randomized, double-blind, placebo-controlled study in women aged 40-60 years who had reported fatigue and had shown high levels of a serum oxidative stress marker. We randomized the participants (n = 60) into equal groups receiving either a beverage containing cacao flavanols (240 mg/200 mL/day) or a placebo for 8 weeks. Before and after the 8-week treatment, we determined the participants' Chalder fatigue scale (CFS) scores, various mood states, autonomic nervous system (ANS) activity levels, and their ANS balance. The results demonstrated that among the mood states, the indicators of negative mood (e.g., depression, fatigue, and anger) and the total mood disturbance score were significantly lower in the cacao group compared to the placebo group after the treatment (p < 0.05). The change in the index of positive mood (i.e., vigor) from baseline to 8 weeks was significantly higher in the cacao group versus the placebo group (p < 0.05). There were no significant between-group differences in the changes in the CFS score or ANS activity level. The consumption of flavanol-rich cacao extract both suppressed negative moods and promoted positive moods in healthy middle-aged women. These results suggest that cacao flavanols may be a useful food material that can improve variable mood conditions in middle-aged women and support their active lives.

Cacao Polyphenol-Rich Dark Chocolate Intake Contributes to Efficient Brain Activity during Cognitive Tasks: A Randomized, Single-Blinded, Crossover, and Dose-Comparison fMRI Study.

Cacao polyphenol-enriched dark chocolate may have beneficial effects on human health, such as facilitating maintaining good performance in long-lasting cognitive tasks. This study examined the effects of dark chocolate intake on improving brain function during cognitive tasks using functional magnetic resonance imaging (fMRI). In this randomized, single-blinded, crossover, and dose-comparison study, 26 healthy middle-aged participants ingested dark chocolate (25 g) either with a low concentration (LC) (211.7 mg) or a high concentration (HC) (635 mg) of cacao polyphenols. Thereafter, their brain activities were analyzed during continuous and effortful cognitive tasks relevant to executive functioning using fMRI in two consecutive 15 min sessions (25 and 50 min after ingestion). We observed significant interaction effects between chocolate consumption and brain activity measurement sessions in the left dorsolateral prefrontal cortex and left inferior parietal lobule. After HC chocolate ingestion, these areas showed lower brain activity in the second session than in the first session; however, these areas showed higher activity in the second session after LC chocolate ingestion. These results suggest that cacao polyphenol-enriched dark chocolate enhances the efficient use of cognitive resources by reducing the effort of brain activity.

Prevention mechanisms of glucose intolerance and obesity by cacao liquor procyanidin extract in high-fat diet-fed C57BL/6 mice.

In this study, we investigated whether cacao liquor procyanidin (CLPr) extract, which consists of 4.3% catechin, 6.1% epicatechin, 39.4% procyanidins and others, ameliorated hyperglycemia and obesity in C57BL/6 mice fed a control or high-fat diet for 13 weeks. CLPr suppressed high-fat diet-induced hyperglycemia, glucose intolerance and fat accumulation in white adipose tissue. CLPr also promoted translocation of glucose transporter 4 (GLUT4) and phosphorylation of AMP-activated protein kinase α (AMPKα) in the plasma membrane of skeletal muscle and brown adipose tissue. Phosphorylation of AMPKα was also enhanced in the liver and white adipose tissue. CLPr up-regulated the gene and protein expression levels of uncoupling protein (UCP)-1 in brown adipose tissue and UCP-3 in skeletal muscle. These results indicate that CLPr is a beneficial food material for the prevention of hyperglycemia and obesity. Activation of AMPKα, translocation of GLUT4 and up-regulation of UCP expression in skeletal muscle and adipose tissue are involved in the molecular mechanisms by which CLPr prevents hyperglycemia and obesity.

Fatty acid tryptamide from cacao elongates Drosophila melanogaster lifespan with sirtuin-dependent heat shock protein expression.

Life span is increasing in developed countries as Japan, and an aging society is becoming a problem. In fact, healthy lifespan is not extended, and it is desired to extend it by functional food. Cacao (Theobroma cacao) contains various active components and is considered a preventative agent against metabolic disease. In addition, it has long been thought that regular cacao intake extends a healthy lifespan. However, there is no direct evidence for this belief. The purpose of this study is to identify the cacao component that elongate the lifespan of D. melanogaster as a model organism and to elucidate its functional mechanism. The activation of sirtuins, a family of NAD+-dependent deacetylases, has been reported to extend the lifespans of various organisms. Heat shock factor 1 is known to be deacetylated by reaction with sirtuins, thereby inducing gene expression of various heat shock proteins by heat stress and effectively extending the lifespan of organisms. Therefore, we evaluated whether components in cacao activate sirtuins and extend the lifespan of D. melanogaster. In the process, we discovered the fatty acid tryptamide as a lifespan-elongating component of cacao. Therefore, we investigated whether the fatty acid tryptamide from cacao upregulates the genes of heat shock proteins. As a result, it was confirmed that the gene expression of multiple heat shock proteins was significantly increased. This suggests that fatty acid tryptamide may activate sirtuins, increase gene expression of heat shock proteins, and elongate the lifespan of D. melanogaster.

Effect of cacao polyphenol-rich chocolate on postprandial glycemia, insulin, and incretin secretion in healthy participants.

OBJECTIVES: There is substantial interest in using dark chocolate to prevent postprandial hyperglycemia. We investigated the effects of cacao polyphenol-rich chocolate on postprandial glycemic and insulinemic responses and whether cacao polyphenol-rich chocolate increases glucagon-like peptide-1 (GLP-1) secretion. METHODS: In a stratified, randomized, crossover study, 48 healthy participants ingested either water (W) or cacao polyphenol-rich chocolate plus water (C) 15 min before a 50 g oral glucose tolerance test (OGTT). Pre- and postprandial concentrations of blood glucose, insulin, free fatty acid, glucagon, and GLP-1 were evaluated. RESULTS: Peak plasma glucose concentrations did not differ significantly between groups W and C; however, plasma glucose concentrations at 120 min in group C were significantly lower than those in group W (P < .01). Postprandial serum insulin and plasma GLP-1 concentrations and incremental serum insulin and plasma GLP-1 area under the curve (AUC)-15-180 min for group C were significantly higher than those for group W (P < .05). When comparing the changes after the OGTT, the incremental plasma glucose AUC0-180 min for group C was significantly lower than that for group W (P < .05), but the incremental serum insulin and plasma GLP-1 AUC0-180 min did not differ significantly between groups W and C. CONCLUSIONS: This study indicated that the intake of cacao polyphenol-rich chocolate before a 50 g OGTT could enhance early insulin and GLP-1 secretion in healthy participants, and illustrates the potential of cacao polyphenol-rich chocolate in managing postprandial glucose excursions.

Cacao liquor procyanidins prevent postprandial hyperglycaemia by increasing glucagon-like peptide-1 activity and AMP-activated protein kinase in mice.

Procyanidins have been reported to possess potential for the prevention of hyperglycaemia. However, there are very few data for procyanidins about the difference the degree of polymerisation (DP) has on anti-hyperglycaemic effects. Moreover, the underlying molecular mechanisms by which procyanidins suppress hyperglycaemia are not yet fully understood. In the present study, we prepared procyanidin fractions with different DP, namely low-DP (DP≤3) and high-DP (DP≥4) fractions, from a cacao liquor procyanidin-rich extract (CLPr). These fractions were administered orally to Institute of Cancer Research (ICR) mice and their anti-hyperglycaemic effects were examined. We found that CLPr and its fractions prevent postprandial hyperglycaemia accompanied by an increase in the plasma glucagon-like peptide-1 (GLP-1) level with or without glucose load. In the absence of glucose load, both fractions increased the plasma insulin level and activated its downstream signalling pathway in skeletal muscle, resulting in promotion of the translocation of GLUT4. Phosphorylation of AMP-activated protein kinase (AMPK) was also involved in the promotion of GLUT4 translocation. High- and low-DP fractions showed a similar activation of insulin and AMPK pathways. In conclusion, cacao liquor procyanidins prevent hyperglycaemia by promoting GLUT4 translocation in skeletal muscle, and both the GLP-1-activated insulin pathway and the AMPK pathway are involved in the underlying molecular mechanism.

Cacao procyanidins reduce plasma cholesterol and increase fecal steroid excretion in rats fed a high-cholesterol diet.

Cocoa powder is rich in polyphenols, such as catechins and oligomeric procyanidins, and has a hypocholesterolemic effect in humans. This study evaluated the principal active components and potential mechanism(s) for the hypocholesterolemic effect of polyphenolic substances from cocoa powder in rats. Male Wistar rats were fed a 1% high-cholesterol diet (HC) or a high-cholesterol diet containing 1% polyphenol extract from cocoa powder (PE) or a mixture of 0.024% catechin and 0.058% epicatechin (CE) for 4 weeks. We also examined the effects of these polyphenolic substances on micellar cholesterol solubility in vitro. The PE group had significantly lower plasma cholesterol concentrations, and had significantly greater fecal cholesterol and total bile acids excretion than the HC group. The CE group diet did not influence plasma cholesterol concentrations, or fecal cholesterol or total bile acids excretion. Micellar solubility of cholesterol in vitro was significantly lower for procyanidin B2 (dimer), B5 (dimer), C1 (trimer) and A2 (tetramer), which are the main components of polyphenol extract from cocoa powder, compared to catechin and epicatechin. These results suggest that oligomeric procyanidins from cocoa powder are the principal active components responsible for the hypocholesterolemic effect, and inhibit the intestinal absorption of cholesterol and bile acids through the decrease in micellar cholesterol solubility.

Inhibitory Effects of Conjugated Epicatechin Metabolites on Peroxynitrite-mediated Nitrotyrosine Formation.

Previously, we identified four metabolites of (-)-epicatechin in blood and urine: (-)-epicatechin-3'-O-glucuronide (E3'G), 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide (4'ME3'G), (-)-epicatechin-7-O-glucuronide (E7G), and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide (3'ME7G) (Natsume et al. Free Radical Biol. Med. 34, 840-849, 2003). The aim of the current study was to compare the antioxidative activities of these metabolites with that of their parent compound. After oral administration of (-)-epicatechin, E3'G and 4'ME3'G were isolated from human urine, and E7G and 3'ME7G isolated from rat urine. We found that these compounds inhibited peroxynitrite-mediated tyrosine nitration, in the following order of potency: E3'G > (-)-epicatechin > E7G = 3'ME7G. = 4'ME3'G. These results demonstrate that the metabolites of (-)-epicatechin retain antioxidative activity on peroxynitrite-induced oxidative damages to some extent.

Polyphenols: Inflammation.

BACKGROUND: Polyphenols widely distributed in plants, fruits and vegetables have received considerable attention on account of their physiological functions, including their antioxidant and anti-inflammatory properties. Some antioxidant components of cacao liquor prepared from fermented and roasted cacao beans, which is a major ingredient of cocoa and chocolate products, have been characterized as flavan-3-ols and procyanidin oligomers. METHODS: This review focuses on a specific group of (-)-epicatechins and their oligomers, the procyanidins, in cacao products. Dietary polyphenols in cacao products have been shown to reduce hypertension, reduce platelet aggregation, improve serum lipids, and lower the incidence of atherosclerosis in animal studies and clinical trials. CONCLUSION: The intake of cacao products reduces hypertension and atherosclerosis on account of their physiological functions as antioxidants and anti-inflammation agents, indicating the mechanisms of prevention of hypertension and atherosclerosis by polyphenols.

Continuous intake of polyphenolic compounds containing cocoa powder reduces LDL oxidative susceptibility and has beneficial effects on plasma HDL-cholesterol concentrations in humans.

BACKGROUND: Cocoa powder is rich in polyphenols such as catechins and procyanidins and has been shown in various models to inhibit LDL oxidation and atherogenesis. OBJECTIVE: We examined whether long-term intake of cocoa powder alters plasma lipid profiles in normocholesterolemic and mildly hypercholesterolemic human subjects. DESIGN: Twenty-five subjects were randomly assigned to ingest either 12 g sugar/d (control group) or 26 g cocoa powder and 12 g sugar/d (cocoa group) for 12 wk. Blood samples were collected before the study and 12 wk after intake of the test drinks. Plasma lipids, LDL oxidative susceptibility, and urinary oxidative stress markers were measured. RESULTS: At 12 wk, we measured a 9% prolongation from baseline levels in the lag time of LDL oxidation in the cocoa group. This prolongation in the cocoa group was significantly greater than the reduction measured in the control group (-13%). A significantly greater increase in plasma HDL cholesterol (24%) was observed in the cocoa group than in the control group (5%). A negative correlation was observed between plasma concentrations of HDL cholesterol and oxidized LDL. At 12 wk, there was a 24% reduction in dityrosine from baseline concentrations in the cocoa group. This reduction in the cocoa group was significantly greater than the reduction in the control group (-1%). CONCLUSION: It is possible that increases in HDL-cholesterol concentrations may contribute to the suppression of LDL oxidation and that polyphenolic substances derived from cocoa powder may contribute to an elevation in HDL cholesterol.

Fructooligosaccharides suppress high-fat diet-induced fat accumulation in C57BL/6J mice.

Two experiments were performed to examine the effects of fructooligosaccharides (FOS) on the development of obesity. In the first experiment, Wistar rats were orally administered a 2.5 g/kg body weight lipid emulsion containing FOS, and the subsequent elevation of plasma triglycerides was significantly suppressed compared with that in rats receiving lipid emulsion alone. In the second experiment, C57BL/6J male mice were fed a high-fat "western" diet with or without 2.5% FOS supplementation (n = 10/group) ad libitum for 12 weeks. Body weight and percent body fat were lower in mice fed FOS than in controls. Furthermore, the weight of the visceral adipose tissue, and the weight and triglyceride content of the liver were significantly lower in the high-fat + FOS group. Fecal excretion of lipids was markedly enhanced by FOS consumption. These results indicate that dietary FOS suppress high-fat diet-induced body fat accumulation, and inhibit intestinal absorption of dietary fat.

Habitual cocoa intake reduces arterial stiffness in postmenopausal women regardless of intake frequency: a randomized parallel-group study.

Arterial stiffness is substantially higher in postmenopausal than in premenopausal women. Daily cocoa intake has been shown to reduce central arterial stiffness in health adults, regardless of age; however, the effect of cocoa-intake frequency on arterial stiffness in postmenopausal women remains unclear. Therefore, the purpose of this study was to investigate the effects of cocoa-intake frequency on arterial stiffness in postmenopausal women. A total of 26 postmenopausal women (mean age ± standard deviation 64±12 years) were randomly assigned to two groups with different cocoa-intake frequencies: one group ingested 17 g of cocoa once daily except on Sundays (every-day group, n=13), and the other ingested 17 g of cocoa twice daily every other day (every-other-day group, n=13). These intake regimens were maintained in both groups for 12 weeks. Carotid-femoral pulse-wave velocity and femoral-ankle pulse-wave velocity were measured in both groups at baseline and again at the end of the 12-week study period. Compared to baseline, both pulse-wave velocities had significantly decreased after the 12-week study period in both groups (P<0.05). However, no significant difference in degree of change was observed between the two groups. Although this study did not include a sedentary control group, these results suggest that regardless of frequency, habitual cocoa intake reduces central and peripheral arterial stiffness in postmenopausal women.

Absorption and urinary excretion of procyanidin B2 [epicatechin-(4beta-8)-epicatechin] in rats.

We evaluated the bioavailability and plasma antioxidative activity after administration of procyanidin B2 [epicatechin-(4beta-8)-epicatechin] in rats. After procyanidin B2 administration, procyanidin B2 is absorbed and excreted in urine, and a portion of the PB2 is degraded to (-)-epicatechin and to the metabolized conjugated and/or methylated (-)-epicatechin internally in the rat. Moreover, PB2 reduces the accumulation of lipid peroxide in plasma oxidized by copper ions.

Structures of (-)-epicatechin glucuronide identified from plasma and urine after oral ingestion of (-)-epicatechin: differences between human and rat.

(-)-epicatechin is one of the most potent antioxidants present in the human diet. Particularly high levels are found in black tea, apples, and chocolate. High intake of catechins has been associated with reduced risk of cardiovascular diseases. There have been several reports concerning the bioavailability of catechins, however, the chemical structure of (-)-epicatechin metabolites in blood, tissues, and urine remains unclear. In the present study, we purified and elucidated the chemical structure of (-)-epicatechin metabolites in human and rat urine after oral administration. Three metabolites were purified from human urine including (-)-epicatechin-3'-O-glucuronide, 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide, and 4'-O-methyl-(-)-epicatechin-5 or 7-O-glucuronide, according to 1H- and 13C-NMR, HMBC, and LC-MS analyses. The metabolites purified from rat urine were 3'-O-methyl-(-)-epicatechin, (-)-epicatechin-7-O-glucuronide, and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide. These compounds were also detected in the blood of humans and rats by LC-MS. The presence of these metabolites in blood and urine suggests that catechins are metabolized and circulated in the body after administration of catechin-containing foods.