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Beeturia and the biological fate of beetroot pigments

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Abstract

Beeturia, the passage of pink or red urine after the ingestion of beetroot, is said to occur in 10-14% of the population, and is more common in iron deficiency and malabsorption. A specific HPLC assay for betacyanins, the red beetroot pigments, in biological fluids was developed to study the prevalence of this apparent polymorphism in humans, and to investigate its basis in rats. Two major peaks were observed in chromatograms of extracts of unpickled beetroot. They had identical UV absorption spectra (lambda max = 535 nm) by diode array analysis, and mass spectrometry indicated that one (betacyanin 1) was betanin or its epimer and the other (betacyanin 2) a disaccharide of betacyanin 1. In a population of 100 normal subjects the 0-8 h urinary recoveries after an oral dose of 60 mg beetroot extract were 0.06-0.54% for betacyanin 1 and 0.01-0.6% for betacyanin 2. The distributions of these data were skewed but not clearly bimodal by visual inspection or by kernel density analysis. Four subjects produced visibly red urine and had betacyanin recoveries at the upper end of the population range. Studies using in situ isolated perfused rat jejunum and liver preparations indicated a negligible absorption of the pigments after 1 h and no detectable metabolism or biliary secretion. Intact anaesthetized rats given i.v. bolus doses of beetroot extract cleared both betacyanins from plasma at the rate of 3.3 +/- 0.9 (SD) ml min-1 (n = 5). The total urinary recovery of both pigments amounted to 80% of the dose, and their renal clearances approached their plasma clearances. These data suggest that beeturia does not arise from deficiencies in hepatic metabolism or renal excretion of betacyanins. After oral administration of beetroot extract to rats the betacyanin content of the stomach decreased rapidly with time but neither the intestines nor the bile duct were stained visibly red. These findings together with those showing instability of the betacyanins in acid conditions suggest that variability in the biological fate of beetroot pigments may be determined largely by gastric pH and emptying rate.

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... It was also observed that after red beetroot or juice consumption the color of urine can turn into slightly reddish, also known as beeturia [11]. However, only 10-14% of humans excrete reddish urine after ingestion [12]. This discoloration is caused by betalains and their metabolites. ...
... The second compound could be identified as the sulfoconjugate of betanidin as it showed the typical neutral loss of m/z 79.9554 representing sulfuric acid. Such conjugates of betanidin have not yet been described in the literature [12,24]. ...
... Cserni and Kocsis confirmed that experience also for Hungary [13]. Watts et al. [12] administered red beetroot extract to rats, and did not observe any discoloration of the bile duct or intestines. It needs closer investigation to what extent the medication or the intake of illegal drugs or medical conditions are connected to the discoloration. ...
Article
During autopsy of a 38 year old man the forensic pathologist noted an atypical purple discoloration of the colon membrane. Hypothesis was that the discoloration could have been caused by ingestion of red beetroot. In order to exclude other toxicological causes for this finding and to analytically verify this hypothesis, colon membrane, blood and urine were screened not only for the typical forensically relevant substances but also for the main chromophoric beetroot compounds employing liquid chromatography high-resolution mass spectrometry (LC-HRMS). Betanin (m/z 551.1495) and its aglycone betanidin (m/z 389.0973) were found in the extracts of colon membrane and urine. Betanin was detected in whole blood, and urinary analysis additionally revealed two metabolites: betanidin glucuronide (m/z 565.1294) and betanidin sulfate (m/z 469.0541)–showing the same fragmentation pattern as betanidin after the characteristic neutral loss of m/z 176.0315 and m/z 79.9554 for glucuronic acid and sulfate, respectively. This is the first time that betacyanins could be analytically confirmed as cause for a purple discoloration of the colon. Urine analysis further revealed that besides betanin itself betanidin phase II metabolites could be detected in human urine.
... Bioavailability is a major issue when considering the potential health effects of dietary antioxidants. Betacyanins have appeared to be absorbed and have been detected in the urine of subjects who consumed red beet juice (8) or beetroot (20). However, in-depth studies of the biokinetics of dietary betalains and of the potential significance in humans are lacking. ...
... Various phytochemicals can be structurally modified during metabolism by conjugation with glucuronic acid, sulfate, or both. Because it has been shown that the absorbed betalains are not metabolized by the hepatic cells (26) and are excreted as such via the urine (20), deconjugated plasma or urine was not considered in our study. After fresh cactus pear fruit pulp was ingested, indicaxanthin and betanin reached their plasma peak concentration 3 h after the fruit meal, which suggested that they were absorbed by the same intestinal portion. ...
... As far as we know, there is no available information about the bioavailability of indicaxanthin from other sources. On the other hand, it has been shown that the urinary recovery of betanin in humans ranges from 0.5% to 1% after ingestion of red beet juice (8) or beetroot extract (20). The extent of absorption of phytochemicals varies greatly because of many factors, including the dietary source, instability of the molecule in the digestive environment, bacterial degradation in the gut, and mechanisms of absorption. ...
Article
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Betalains were recently identified as natural antioxidants. However, little is known about their bioavailability from dietary sources. The objective was to evaluate the bioavailability of betalains from dietary sources. The plasma kinetics and urinary excretion of betalains were studied in healthy volunteers (n = 8) after a single ingestion of 500 g cactus pear fruit pulp, which provided 28 and 16 mg indicaxanthin and betanin, respectively. The incorporation of betalains in LDL and the resistance of the particles to ex vivo-induced oxidation was also researched. Betanin and indicaxanthin reached their maximum plasma concentrations 3 h after the fruit meal and declined according to first-order kinetics. The half-life of betanin (0.94 +/- 0.07 h) was shorter than that of indicaxanthin (2.36 +/- 0.17 h). Both compounds had disappeared from plasma by 12 h after intake. The urinary excretion of indicaxanthin and betanin over 12 h represented 76 +/- 3.0% and 3.7 +/- 0.2%, respectively, of the ingested compounds. LDL isolated 3 and 5 h after the fruit meal incorporated betalains at concentrations of 100.5 +/- 11 and 50 +/- 7.2 pmol/mg LDL protein, respectively. In addition, the particles appeared more resistant to ex vivo-induced oxidative injury than did the samples isolated before fruit ingestion (P < 0.05)-the higher the amount of betalains incorporated, the higher the resistance. The concentrations of vitamin E and beta-carotene in LDL did not change significantly after fruit ingestion. Our results show that cactus pear fruit is a source of bioavailable betalains and suggest that indicaxanthin and betanin may be involved in the observed protection of LDL against ex vivo-induced oxidative modifications.
... Nonexcretors simply produce too little pigment to be visible to the unaided eye (Pearcy et al., 1992; Mitchell, 1996). This was corroborated by an elegant study wherein urine samples from 100 subjects who had previously ingested 60 mg of beetroot pigment were examined by high-pressure liquid chromatography and all were shown to contain small amounts of pigment, but in many the concentrations were too low for them to appear red (Watts et al., 1993). Data from eight individuals who undertook a repeat study within 1 week showed that the beeturia was reproducible, but four subjects who ingested the same quantity of beetroot on five separate occasions spaced over several months showed variation ranging from good to poor excretion (Pearcy et al., 1992). ...
... Furthermore, by varying the amount of beetroot consumed during a single meal, it has been alluded that this may be, and probably is, a dose-dependent phenomenon. Furthermore, the type of beetroot (variety, preparation, source) used influenced the outcome; susceptible individuals who gave an intense coloration with one variety gave virtually normal urine with another (Pearcy et al., 1992; Watts et al., 1993). It is known that the times of planting and harvesting greatly influence the pigment content of the crop and that concentrated beetroot extract is added to certain brands to enhance the coloration of their finished products (Shannon, 1972). ...
... These pigments are known to behave as redox acid/base indicators and are structurally unstable at the extremes of pH, loosing their color in alkaline conditions and undergoing irreversible decomposition (red to yellow) in acid solution. Optimal stability exists between pH 4 to 5 (von Elbe et al., 1974; Huang and von Elbe, 1987; Watts et al., 1993; Eastwood and Nyhlin, 1995). If pigment is present, therefore, the resulting color intensity is dependent upon the urinary pH. ...
Article
Anecdotal observations scattered throughout the literature have often provided clues to underlying variations in humans' ability to handle dietary chemicals. Beetroot, the red root of the garden beet used extensively as a food source, is known to produce red urine in some people following its ingestion, whereas others appear to be able to eat the vegetable with impunity. Asparagus, a vegetable whose young shoots have been eaten as a delicacy since the times of the Roman Empire, has been associated with the production of a malodorous urine smelling like rotten cabbage. Those who produce this odor assume that everyone does, and those who do not produce it have no idea of its potential olfactory consequences. These two examples, where the population appears divided in its ability to process food products or more precisely the chemicals contained within them, are reviewed in detail in this article.
... Compared with the water controls, red beet juice consumption resulted in a signi fi cantly increased urinary excretion of total phenolics (51% of the administered phenolics). Similar low recovery (0.01-0.6%) of intact betalains excreted in the urine were observed in an earlier study with a larger population of 100 healthy subjects after an 8-h period of beetroot ingestion (Watts et al. 1993 ) . ...
... Consumption of red beetroot extract produces red or pink coloration of urine and feces, known as beeturia (also called betaninuria, named after betanin, the major constituent of the extract) in 10-14% of the population (Mitchell 2001 ;Watson et al. 1963 ;Watts et al. 1993 ) . It appears to be more prevalent among those with pre-existing iron de fi ciency and malabsorption conditions. ...
... The susceptible individuals are unable to completely break down the red pigment in their stomach and colon, and thus more of it becomes available for re-absorption and bodily re-circulation. Two major contributing factors for this condition are higher gastric pH and a longer emptying rate, which increase the absorption rate of the red colorant from the ingested beetroot extract (Pavlov et al. 2005 ;Watts et al. 1993 ) . ...
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Currently, there is considerable interest in the anticancer effects of red beetroot (Beta vulgaris L.) pigment extract, which is used worldwide as red food color E162 and as a natural colorant in cosmetics and drugs. Of particular significance is its broad spectrum of multi-organ antitumor activity demonstrable in laboratory animal models. Further, this nontoxic plant extract, when used in combination with potent anticancer drugs such as doxorubicin (Adriamycin), has the potential to act synergistically and mitigate treatment-related drug toxicity. Betanin, the betacyanin constituent primarily responsible for red beet color, is an antioxidant with an exceptionally high free radical-scavenging activity and is a modulator of oxidative stress. Research focused on anticancer activities of beetroot extract, in animal models, has unraveled their potential benefits as chemopreventive and chemotherapeutic agents, although further progress is needed on the identification and elucidation of anticancer mechanism(s) of individual active constituent(s) in additional well-designed experimental models and clinical trials, as discussed in this chapter.
... The susceptibility of individuals to beeturia has been attributed to genetic factors, allergies, and iron maladsorption. On the other hand, the extent to which individuals absorb and excrete betalains may be simply related to dynamics of digestion, specifically, variations in gastric pH and emptying rate (47). In any event, the range in bioavailability among individuals (human or animal) may prohibit any clear and statistically significant demonstration on pharmacological effect of betalains in virtually any feeding trial. ...
... The recovery of intact betalains excreted in the urine of 100 "normal (human) subjects", defined as those free of obvious or documented medical problems, ranged from 0.01 to 0.6% (47). More recent studies employing human subjects yielded estimates of 0.5-0.9% ...
Article
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Crude aqueous and ethanolic extracts of root tissue of red (Rd) and high-pigment (HP) beet (Beta vulgaris L.) strains exhibited antioxidant and phase II enzyme-inducing activities, and these extracts were fractionated using Sephadex LH-20 chromatography. These bioactivities tended to become co-enriched in early and late eluting fractions, comprising 5-25% of the material recovered from the column. Liquid chromatography-mass spectrometry (MS) was used to resolve and identify multiple betalain components in the most potent quinone reductase (QR)-inducing fractions. Active fractions were found to contain vulgaxanthins I and II, and (iso)betanin, but other components remained unidentified. Two of the isolated active fractions were incorporated into rodent diets at 10-150 ppm over a 2-mo period to assess bioavailability and in vivo efficacy for phase II enzyme induction in various organs. No statistically significant effect of diet was obtained, and wide ranges of tissue enzyme levels among individual animals were observed. This lack of effect and diversity in response to diet may be related to the wide range in absorptive capacity of and/or insufficient level or enrichment of the active agents or to difficulties in assessing such activity in vivo. Subsequent to the animal studies, betanin was isolated in pure form, identified by MS analysis, and confirmed to be QR inducers in the bioassay.
... It should be noted that like doxorubicin, the red beetroot extract also causes red or pink coloration of urine, known as beeturia [30]. The susceptible individuals are the ones who are unable to break it down completely in their stomach and colon, and thus more of it becomes available for absorption and bodily circulation. ...
... The susceptible individuals are the ones who are unable to break it down completely in their stomach and colon, and thus more of it becomes available for absorption and bodily circulation. Two major contributing factors for this condition are higher gastric pH which decreases the non-enzymatic breakdown and longer emptying rate which increases the absorption of this red pigment [26,30]. ...
Article
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Previous cancer chemoprevention studies from our laboratories and by other investigators have demonstrated that the extract of red beetroot (Beta vulgaris L.), the FDA approved red food color E162, can be effective in suppressing the development of multi-organ tumors in experimental animals. To further explore this finding, we have compared the cytotoxic effect of the red beetroot extract with anticancer drug, doxorubicin (adriamycin) in the androgen-independent human prostate cancer cells (PC-3) and in the well-established estrogen receptor-positive human breast cancer cells (MCF-7). This red colored anticancer antibiotic was selected for comparative cytotoxic study because its chemical structure with a planar configuration of an aromatic chromophore attached to a sugar molecule is remarkably similar to that of betanin, the beetroot extract constituent primarily responsible for its red color. Both doxorubicin and the beetroot extract exhibited a dose-dependent cytotoxic effect in the two cancer cell lines tested. Although the cytotoxicity of the beetroot extract was significantly lower when compared to doxorubicin, it continued to decrease the growth rate of the PC-3 cells (3.7% in 3 days vs. 12.5% in 7 days) when tested at the concentration of 29 µg/ml. In contrast, doxorubicin, at the same concentration level, completely inhibited the growth of the PC-3 cells in three days. Similarly, comparative studies in the normal human skin FC and liver HC cell lines showed that the beetroot extract had significantly lower cytotoxic effect than doxorubicin (8.6% vs. 100%, respectively, at 29 µg/ml concentration of each, three-day test period). The results suggest that betanin, the major betacyanin constituent, may play an important role in the cytotoxicity exhibited by the red beetroot extract. Further studies are needed to evaluate the chemopreventive potentials of the beetroot extract when used alone or in combination with doxorubicin to mitigate the toxic side-effects of the latter.
... The oral bioavailability of betalains, similar to that of anthocyanins, is estimated as rather low [58,111]. The exact mechanisms of absorption, metabolism and excretion of betalains have yet not been fully clarified [23,94,95,[111][112][113]. So far, no glucuronides, sulphates or methylated betalain conjugates have been detected in plasma and urine [111]. ...
... Absorbed betanin is primarily excreted via urine. Nevertheless, the renal excretion of betanin is rather low with <4% of the applied dose [23,95,[111][112][113]. Thus, it is assumed that betanin is isomerized to isobetanin which represents the main betanin metabolite in urine [23]. ...
Article
Betalains are water-soluble nitrogen-containing pigments which are subdivided in red-violet betacyanins and yellow-orange betaxanthins. Due to glycosylation and acylation betalains exhibit a huge structural diversity. Betanin (betanidin-5-O-β-glucoside) is the most common betacyanin in the plant kingdom. According to the regulation on food additives betanin is permitted quantum satis as a natural red food colorant (E162). Moreover, betanin is used as colorant in cosmetics and pharmaceuticals.Recently, potential health benefits of betalains and betalain-rich foods (e.g., red beet, Opuntia sp.) have been discussed. Betanin is a scavenger of reactive oxygen species and exhibits gene-regulatory activity partly via Nrf2-dependent signaling pathways. Betanin may induce phase II enzymes and antioxidant defense mechanisms. Furthermore, betanin possibly prevents LDL oxidation and DNA damage. Potential blood pressure lowering effects of red beet seem to be mainly mediated by dietary nitrate rather than by betanin per se.This article is protected by copyright. All rights reserved
... Whereas previous investigations have shown that renal metabolism plays a fairly insignificant role in betanin excretion, it is purported that the majority of its metabolism occurs within the gut. This is likely due to gastric pH at the time of ingestion, along with gastric emptying rate (Frank et al., 2005;Kanner, Harel, & Granit, 2001;Watts, Lennard, Mason, Tucker, & Woods, 1993). Since a change in 24-h or single sample Ucol was not observed in this investigation, it is possible that the acidity of the stomach (pH ~ 2) degraded the betanin (which is most stable at a pH of about 4-6), and therefore beeturia was minimal (Elbe, Maing, & Amundson, 1974). ...
Article
Urine color (Ucol) as a hydration assessment tool provides practicality, ease of use, and correlates moderately to strongly with urine specific gravity (Usg) and urine osmolality (Uosm). Indicative of daily fluid turnover, along with solute and urochrome excretion, Ucol may also reflect dietary composition. Thus, the purpose of this investigation was to determine the efficacy of Ucol as a hydration status biomarker after nutritional supplementation with beetroot (880 mg), vitamin C (1000 mg), and riboflavin (200 mg). Twenty males (Mean ± SD; age, 21 ± 2 y; body mass, 82.12 ± 15.58 kg; height, 1.77 ± 0.06 m) consumed a standardized breakfast and collected all urine voids on one control day (CON), and one day after consuming a standardized breakfast and a randomized and double-blinded supplement (SUP), over 3 weeks. Participants replicated exercise and diet for one day before CON, and throughout CON and SUP. Ucol, Usg, Uosm, and urine volume were measured in all 24-h samples, and Ucol and Usg were measured in all single samples. Ucol was a significant predictor of single sample Usg after all supplements (p<0.05). Interestingly, 24-h Ucol was not a significant predictor of 24-h Usg and Uosm after riboflavin supplementation (p=0.20, p=0.21). Further, there was a significant difference between CON and SUP 24-h Ucol only after riboflavin supplementation (p<0.05). In conclusion, this investigation suggests that users of the UCC should consider riboflavin supplementation when classifying hydration status and utilize a combination of urinary biomarkers (e.g., Usg and Ucol), both acutely and over 24-h.
... Both phytochemicals have been shown to inhibit microsomal membrane oxidation (16) and the oxidation of human LDL in vitro (16,19). More importantly, as dietary components, betanin and indicaxanthin are bioavailable (16,20,21) and have recently been evaluated in human plasma and LDL over an 8 h period after the consumption of cactus pear fruits (21). To further investigate the postabsorbitive distribution of betalains, in this work we checked the presence of betanin and indicaxanthin in human red blood cells (RBCs) after a meal consisting of cactus pear fruit pulp. ...
Article
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Betalain pigments are bioavailable phytochemicals recently acknowledged as natural radical scavengers. This work, which extends previous research on the postabsorbitive fate of dietary betalains, investigated the distribution of betanin and indicaxanthin in red blood cells (RBCs) isolated from healthy volunteers (n = 8), before and during the 1-8 h interval after a cactus pear fruit meal, and the potential antioxidative activity of the pigments in these cells. A peak concentration of indicaxanthin (1.03 +/- 0.2 microM) was observed in RBCs isolated at 3 h after fruit feeding, whereas the concentration at 5 h was about half, and even smaller amounts were measured at 8 h. Indicaxanthin was not detected at 1 h. Betanin (30.0 +/- 5.2 nM) was found only in RBCs isolated at 3 h from fruit feeding. In comparison with homologous RBCs before fruit ingestion, a significant delay (P < 0.05) of the onset of an ex vivo cumene hydroperoxide (cumOOH)-induced hemolysis was evident in the RBCs isolated at 3 h (33.0 +/- 4.5 min) and at 5 h (16.0 +/- 2.0 min). Neither vitamins C and E nor GSH was modified in the RBCs at any time point. Blood collected from the same volunteers after a 12-h fasting was incubated with the purified betalains in the range of 5-25 microM, to enrich the erythrocytes with either betanin or indicaxanthin, and then the cells were exposed to cumOOH. When compared to the relevant nonenriched cells, the betalain-enriched erythrocytes exhibited an enhanced resistance to the cumOOH-induced hemolysis, which was positively correlated (r (2) = 0.99) to the amount of the incorporated compound. On a micromolar basis, betanin and indicaxanthin showed a comparable effectiveness. Taken together, these findings provide evidence that human RBCs incorporate dietary betalains and support the concept that these phytochemicals may offer antioxidative protection to the cells.
... The phenomenon of 'beeturia', the excretion of pink or raspberry-red urine following the ingestion of beetroot, has been observed and elucidated since the 1950s [33][34][35]. After initially attributing the fact that only 10-14% of humans produce a reddish urine after consumption of beetroot or its juice to genetic and thus metabolic reasons, it was eventually proven that the interindividual variations in urinary excretion of betanin and isobetanin are predominantly (if not exclusively) determined by their gastronintestinal absorption [35][36][37]. A possible reason for the comparably frequent observation of reddish urine samples in sports drug testing might be the recently increasing interest in dietary nitrate supplementation, which was described to improve exercise performance [38], and the fact that beetroot juice in particular is naturally rich in nitrate. ...
Article
Manipulation of urine specimens provided by elite athletes for doping control purposes has been reported several times in the past, and in most of these cases urine substitution was eventually proven. Recent findings of suspected and substantiated manipulation have outlined the complexity and diversity of tampering options, sample appearance alterations resulting from non-manipulative influence, and the analytical challenges arising from these scenarios. Using state-of-the-art mass spectrometric and immunological doping control and forensic chemistry methodologies, four unusual findings were observed. One sports drug testing specimen was found to contain an unusually high content of saccharides accompanied by hordenine and Serpine-Z4, while no endogenous steroid (e.g. testosterone, epitestosterone, androsterone and etiocholanolone) was detected. This specimen was identified as non-alcoholic beer filled into the doping control sample container, constituting an undisputed doping offense. A doping control sample of bright green color was received and found to contain residues of methylene blue, which is not considered relevant for doping controls as no masking or manipulative effect is known. In addition, the number of urine samples of raspberry to crimson red coloration received at doping control laboratories has constantly increased during the last years, attributed to the presence of hemoglobin or betanin/isobetanin. Also here, no doping rule violation was given and an impact on routine analytical results was not observed. Finally, a total of 8 sports drug testing samples collected at different competition sites was shown to contain identical urine specimens as indicated by steroid profile analysis and conclusively proven by DNA-STR (short tandem repeat) analysis. Here, the athletes in question were not involved in the urine substitution act but the doping control officer was convicted of sample manipulation.
... A similar effect was observed in our previous study on the influence of beetroot products on neutrophil ROS production, particularly for the beetroot juice subjected to transport and digestion in artificial gastrointestinal tract which reduced both parameters by 64% and 17%, respectively (Zielińska-Przyjemska et al., 2009) suggesting that betanin might be responsible for beetroot activity in the stimulated neutrophils. This suggestion is further supported by the fact that the absorbed betalains are not metabolized by hepatic cells and are excreted as such via urine (Watts et al., 1993), so in this form it can also affect neutrophils not only in vitro but also in vivo. PMA is known to stimulate NADPH oxidase through phosphorylation of the p47 PHOX subunits in PKC-dependent mechanism, which dramatically amplified the luminol chemiluminescence (Babior, 2000;Groemping et al., 2003;Mao et al., 2010). ...
Article
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The aim of this study was to evaluate the effect of betanin, one of the beetroot major components, on ROS production, DNA damage and apoptosis in human resting and stimulated with phorbol 12-myristate13-acetate polymorphonuclear neutrophils, one of the key elements of the inflammatory response. Incubation of neutrophils with betanin in the concentration range 2–500 µm resulted in significant inhibition of ROS production (by 15–46%, depending on the ROS detection assay). The antioxidant capacity of betanin was most prominently expressed in the chemiluminescence measurements. This compound decreased also the percentage of DNA in comet tails in stimulated neutrophils, but only at the 24 h time point. In resting neutrophils an increased level of DNA in comet tails was observed. Betanin did not affect the activity of caspase-3, in resting neutrophils, but significantly enhanced the enzyme activity in stimulated neutrophils. The western blot analysis showed, however, an increased level of caspase-3 cleavage products as a result of betanin treatment both in resting and stimulated neutrophils. The results indicate that betanin may be responsible for the effect of beetroot products on neutrophil oxidative metabolism and its consequences, DNA damage and apoptosis. The dose and time dependent effects on these processes require further studies. Copyright
... The urinary recovery of indicaxanthin and betanin at 12 h represented about 75% and 3.5%, respectively, of the ingested compound. Information about the bioavailability of betalains from other sources have been obtained by measurement of urinary excretion of betanin after ingestion of beetroot juice (Frank et al., 2005;, or beetroot extracts (Watts et al., 1993). These papers show that the bioavailability of betanin was no more than 1% of the administered compound. ...
Article
The health-promoting properties of edible fruits from Opuntia ficus-indica have been the object of recent interest. Scientific evidence has been provided about benefits from the consumption of the fruits in humans, with special attention to the non-nutritive components as potentially active antioxidant phytochemicals. Information about bioavailability and bioactivity of betalains, mode of action as antioxidants in cells, and other biological models are now available. The use of cactus pear components as nutraceuticals and functional food is discussed.
... With core structures formed by the condensation between carbonyl and amine moieties (Figure 1), betalains are categorised into red-violet betacyanins (e.g., betanin, phyllocactin) and yellow-orange betaxanthins (e.g., vulgaxanthin, indicaxanthin). The molecules are susceptible to various types of decomposition, such as Schiff base hydrolysis and decarboxylation with their stability being maintained at pH 4-7, low temperature, darkness and absence of oxygen [2][3][4]. ...
Article
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The present study aimed to compare the absorption and transport patterns of three main betalains, betanin, vulgaxanthin I and indicaxanthin, into intestinal epithelial cells and to assess their distinct molecular effects on inflammatory and redox-related cell signalling in association with their radial scavenging potencies. All three betalains showed anti-inflammatory effects (5–80 μM), reflected by attenuated transcription of pro-inflammatory mediators such as cyclooxygenase-2 and inducible NO-synthase. Concomitant increases in antioxidant enzymes such as heme oxygenase-1 were only observed for betanin. Moreover, betanin uniquely demonstrated a potent dose-dependent radical scavenging activity in EPR and cell-based assays. Results also indicated overall low permeability for the three betalains with Papp of 4.2–8.9 × 10−7 cm s−1. Higher absorption intensities of vulgaxanthin and indicaxanthin may be attributed to smaller molecular sizes and greater lipophilicity. In conclusion, betanin, vulgaxanthin I and indicaxanthin have differentially contributed to lowering inflammatory markers and mitigating oxidative stress, implying the potential to ameliorate inflammatory intestinal disease. Compared with two betaxanthins, the greater efficacy of betanin in scavenging radical and promoting antioxidant response might, to some extent, compensate for its poorer absorption efficiency, as demonstrated by the Caco-2 cell model.
... Betacyanins were present in much higher quantities. The bioavailability of these compounds is however uncertain, but it appears to be very low with typical estimates from <1% to 4% of an oral dose, with some individuals having far greater absorption 69,70 . ...
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Dietary nitrate supplementation has been shown to reduce the oxygen (O2) cost of exercise and enhance exercise tolerance in healthy individuals. This study assessed whether similar effects could be observed in individuals with type 2 diabetes (T2DM). In a randomized, double-blind, placebo-controlled crossover study, 48 participants with T2DM supplemented their diet for 4 days with either nitrate-rich beetroot juice (70 ml/day, 6.43 mmol nitrate/day) or nitrate-depleted beetroot juice as placebo (70 ml/day, 0.07 mmol nitrate/day). After each intervention period, resting plasma nitrate and nitrite concentrations were measured subsequent to participants completing moderate-paced walking. Pulmonary gas exchange was measured to assess the O2 cost of walking. After a rest period, participants performed the 6-min walk test (6MWT). Relative to placebo, beetroot juice resulted in a significant increase in plasma nitrate (placebo, 57±66 vs beetroot, 319±110 µM; P < 0.001) and plasma nitrite concentration (placebo, 680±256 vs beetroot, 1065±607 nM; P < 0.001). There were no differences between placebo juice and beetroot juice for the O2 cost of walking (946±221 vs 939±223 ml/min, respectively; P = 0.59) and distance covered in the 6MWT (550±83 vs 554±90 m, respectively; P = 0.17). Nitrate supplementation did not affect the O2 cost of moderate-paced walking or improve performance in the 6MWT. These findings indicate that dietary nitrate supplementation does not modulate the response to exercise in individuals with T2DM.
... This 35% decrease in betanin contents observed after gastric digestion is due to its impaired stability at acidic pH 2. It is known that betalains exhibit stability at pH ranging from 3 and 7 [18]. A significant decrease in betacyanin stability in a solution containing hydrochloric acid at pH 2.0 at 37 • C was observed, whereas betacyanins maintained at pH 4.7 were less susceptible to degradation [29]. In acid pH, the betanin structure can be degraded in C-17 decarboxylation, dehydrogenation and cleavage of betalamic acid and cyclo-Dopa-5-O-βglycoside [2,30]. ...
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Betanin is the only betalain approved for use in food and pharmaceutical products as a natural red colorant. However, the antioxidant power and health-promoting properties of this pigment have been disregarded, perhaps due to the difficulty in obtaining a stable chemical compound, which impairs its absorption and metabolism evaluation. Herein, betanin was purified by semi-preparative HPLC-LC/MS and identified by LC-ESI(+)-MS/MS as the pseudomolecular ion m/z 551.16. Betanin showed significant stability up to −30 • C and mild stability at chilling temperature. The stability and antioxidant ability of this compound were assessed during a human digestion simulation and ex vivo colon fermentation. Half of the betanin amount was recovered in the small intestine digestive fluid and no traces were found after colon fermentation. Betanin high antioxidant ability was retained even after simulated small intestine digestion. Betanin, besides displaying an inherent colorant capacity, was equally effective as a natural antioxidant displaying peroxy-radical scavenger ability in pork meat. Betanin should be considered a multi-functional molecule able to confer an attractive color to frozen or refrigerated foods, but with the capacity to avoid lipid oxidation, thereby preserving food quality. Long-term supplementation by beetroot, a rich source of betanin, should be stimulated to protect organisms against oxidative stress.
... Other examples of biological and therapeutical activities can be found elsewhere [148,149]. Interestingly, the bioavailability of betalains is low, [30] and beeturia, the peculiar passage of red or pink urine upon consumption of betalain-rich food, or [216], has greatly stimulated the study of the biodistribution and metabolism of betalains [217]. ...
... Finally, however, it was established that beeturia is not caused by a genetic trait or disturbed iron level as a single factor but rather due to limited metabolic ability to process betalains from a given food matrix, being a resultant of the amount of the betalaincontaining food consumed, simultaneous ingestion of some organic acids such as oxalic acid or ascorbic acid, and the rate of gastric emptying. Thus, beeturia is not a physiological dysfunction but rather a food idiosyncrasy [286,287]. ...
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Betalains are water-soluble pigments present in vacuoles of plants of the order Caryophyllales and in mushrooms of the genera Amanita, Hygrocybe and Hygrophorus. Betalamic acid is a constituent of all betalains. The type of betalamic acid substituent determines the class of betalains. The betacyanins (reddish to violet) contain a cyclo-3,4-dihydroxyphenylalanine (cyclo-DOPA) residue while the betaxanthins (yellow to orange) contain different amino acid or amine residues. The most common betacyanin is betanin (Beetroot Red), present in red beets Beta vulgaris, which is a glucoside of betanidin. The structure of this comprehensive review is as follows: Occurrence of Betalains; Structure of Betalains; Spectroscopic and Fluorescent Properties; Stability; Antioxidant Activity; Bioavailability, Health Benefits; Betalains as Food Colorants; Food Safety of Betalains; Other Applications of Betalains; and Environmental Role and Fate of Betalains.
... Other examples of biological and therapeutical activities can be found elsewhere [148,149]. Interestingly, the bioavailability of betalains is low, [30] and beeturia, the peculiar passage of red or pink urine upon consumption of betalain-rich food, or [216], has greatly stimulated the study of the biodistribution and metabolism of betalains [217]. ...
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An overview is provided of the status of research on the antioxidant and radical-scavenging properties of betalains, water-soluble alkaloids found in plants, fungi and bacteria. Together with anthocyanins, betalains are responsible for most of the red, purple and blue colors of fruits and flowers, although both classes of secondary metabolites are mutually exclusive in nature. The 1,7-diazaheptamethinium scaffold of betalains promotes their radical scavenging properties, which involve the occurrence of proton-coupled electron transfer. Betalains derived from cyclo-DOPA, namely betacyanins, are antioxidants as potent as epicatechin gallate from green tea. The other betalains, classified as betaxanthins, also show high antioxidant potential whether they are phenolic or not. Since much of the current understanding of the antioxidant properties of betalains has been derived from studies of model compounds that mimic the reactivity patterns of natural pigments, comprehensive data on the antioxidant action of both natural and pseudo-natural betalains are presented.
... Beturia does not arise from deficiency in hepatic metabolism or renal excretion of betacyanins [73], but the reasons of the appearing of the pigments in urine are importance being solely in differential diagnosis, for example, from haemoglobinuria [74]. Perhaps, beturia is somehow linked to the iron metabolism. ...
... 3 Beeturia, the passage of pink or red urine after the ingestion of beetroot, is said to occur in 10%-14% of the population, is more common in iron deficiency and malabsorption, and is caused by the presence of betacyanins. 17 Medications implicated in causing red urine include senna, anthraquinone and phenolphthalein-containing laxatives, doxorubicin, and phenothiazines. 3 ...
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... Whereas previous investigations have shown that renal metabolism plays a fairly insignificant role in betanin excretion, it is purported that the majority of betanin metabolism occurs within the gut. This is likely due to gastric pH at the time of ingestion, along with gastric emptying rate 29,31,32 . Since a change in U col was not observed in this investigation, it is possible that the acidity of the stomach (pH ~ 2) degraded the betanin (which is most stable at a pH of about 4-5), so that beeturia could not result. ...
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Anthocyanins and betalaines are mutually exclusive in plants. The chief red pigment of beetroot is betanin. Its extraction gives low yield and a large proportion of sugar. This may be removed by aerobic fermentation. The chemistry of betanin and the synthesis of betanidin are described. Betanin is stable between pH 3·0 and 7·0; outside this range there are appreciable losses. Heating can also change the red to light brown. The presence of air and light accelerates degradation. Water also aids degradation, suggesting its use in foodstuffs of low moisture content.
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The uptake, metabolism and excretion of betanin from beetroot extract were studied in the rat after iv injection or peroral administration in vivo, and in the isolated perfused liver in vitro. When injected iv, betanin was almost completely recovered in the urine. When given orally only 3% was recovered in the urine and 3% in the faeces after 24 hr. In the isolated perfused liver very little betanin was found in the bile, and most of the added betanin was recovered from the perfusion fluid. In studies in vitro it was found that betanin was largely metabolized by the tissues lining the gastro-intestinal tract. It is concluded that orally-administered betanin is poorly absorbed, and that the majority of it is metabolized in the gut. Betanin injected iv had effects on the cardiovascular system, transiently increasing the blood pressure and heart rate. It also increased the magnitude of the contractions of an isolated portal vein, in vitro. Both the in vivo and the in vitro effects could be partially blocked by specific adrenergic and cholinergic blockers, but the mechanism of the cardiovascular effects of betanin remains to be determined.
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IT has been recognized for many years that humans excrete methanethiol (methyl mercaptan) after eating asparagus, and it has been assumed that this character is universal1,2. We have found, however, that while some subjects excrete detectable amounts of methanethiol after ingesting only three or four sticks of asparagus, no significant amount of the compound appears in the urine of others after ingestion of as much as a pound of asparagus. Biochemical investigations of this metabolic difference are being made in collaboration with Dr. P. W. Kent. Nencki's1 identification of the odorous substance in urine as methanethiol has been confirmed by isolation of the corresponding silver mercaptide.