Effect of Chemical Refining on the Reduction of ß-Carboline Content in Sesame Seed Oil.

ß-carbolines (harman and norharman) are potentially mutagenic and have been reported in some vegetable oils. Sesame seed oil is obtained from roasted sesame seeds. During sesame oil processing, roasting is the key procedure to aroma enhancement, in which ß-carbolines are produced. Pressed sesame seed oils cover most market share, while leaching solvents are used to extract oils from the pressed sesame cake to improve the utilization of the raw materials. ß-carbolines are nonpolar heterocyclic aromatic amines with good solubility in leaching solvents (n-hexane); therefore, the ß-carbolines in sesame cake migrated to the leaching sesame seed oil. The refining procedures are indispensable for leaching sesame seed oil, in which some small molecules can be reduced. Thus, the critical aim is to evaluate the changes in ß-carboline content during the refining of leaching sesame seed oil and the key process steps for the removal of ß-carbolines. In this work, the levels of ß-carbolines (harman and norharman) in sesame seed oil during chemical refining processes (degumming, deacidification, bleaching and deodorization) have been determined using solid phase extraction and high performance liquid chromatography-mass spectrometry (LC-MS). The results indicated that in the entire refining process, the levels of total ß-carbolines greatly decreased, and the adsorption decolorization was the most effective process in reducing ß-carbolines, which might be related to the adsorbent used in the decolorization process. In addition, the effects of adsorbent type, adsorbent dosage and blended adsorbent on ß-carbolines in sesame seed oil during the decolorization process were investigated. It was concluded that oil refining can not only improve the quality of sesame seed oil, but also reduce most of the harmful ß-carbolines.

Solid-Contact Potentiometric Sensors Based on Main-Tailored Bio-Mimics for Trace Detection of Harmine Hallucinogen in Urine Specimens.

All-solid-state potentiometric sensors have attracted great attention over other types of potentiometric sensors due to their outstanding properties such as enhanced portability, simplicity of handling, affordability and flexibility. Herein, a novel solid-contact ion-selective electrode (SC-ISE) based on poly(3,4-ethylenedioxythiophene) (PEDOT) as the ion-to-electron transducer was designed and characterized for rapid detection of harmine. The harmine-sensing membrane was based on the use of synthesized imprinted bio-mimics as a selective material for this recognition. The imprinted receptors were synthesized using acrylamide (AA) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. The polymerization process was carried out at 70 °C in the presence of dibenzoyl peroxide (DBO) as an initiator. The sensing membrane in addition to the solid-contact layer was applied to a glassy-carbon disc as an electronic conductor. All performance characteristics of the presented electrode in terms of linearity, detection limit, pH range, response time and selectivity were evaluated. The sensor revealed a wide linearity over the range 2.0 × 10-7-1.0 × 10-2 M, with a detection limit of 0.02 µg/mL and a sensitivity slope of 59.2 ± 0.8 mV/hamine concentration decade. A 40 mM Britton-Robinson (BR) buffer solution at pH of 6 was used for all harmine measurements. The electrode showed good selectivity towards harmine over other common interfering ions, and maintained a stable electrochemical response over two weeks. After applying the validation requirements, the proposed method revealed good performance characteristics. Method precision, accuracy, bias, trueness, repeatability, reproducibility, and uncertainty were also evaluated. These analytical capabilities support the fast and direct assessment of harmine in different urine specimens. The analytical results were compared with the standard liquid chromatographic method. The results obtained demonstrated that PEDOT/PSS was a promising solid-contact ion-to-electron transducer material in the development of harmine-ISE. The electrodes manifested enhanced stability and low cost, which provides a wide number of potential applications for pharmaceutical and forensic analysis.

Fast determination of harmala alkaloids in edible algae by capillary electrophoresis mass spectrometry.

The use of algae as a foodstuff is rapidly expanding worldwide from the East Asian countries, where they are also used for medical care. Harmala alkaloids (HAlk) are a family of bioactive compounds found in the extracts of some plants, including wakame (Undaria pinnatifida), an edible marine invasive algae. HAlks are based on a characteristic ß-carboline structure with at least one amino ionizable group. In this work, we report the successful separation of a mixture of six HAlks (harmine, harmaline, harmol, harmalol, harmane, and norharmane) by capillary electrophoresis ion-trap mass spectrometry (CE-IT-MS) in less than 8 min. Optimum separation in fused-silica capillaries and detection sensitivity in positive-ion mode were achieved using a background electrolyte (BGE) with 25 mmol L(-1) ammonium acetate (pH 7.8) and 10% (v/v) methanol, and a sheath liquid with 60:40 (v/v) isopropanol-water and 0.05% (v/v) formic acid. The separation method was validated in terms of linearity, limits of detection and quantification, repeatability, and reproducibility. Later, a sample pretreatment was carefully optimized to determine HAlks in commercial wakame samples with excellent recovery and repeatability. For the complex wakame extracts, the MS-MS fragmentation patterns of the different HAlks were useful to ensure a reliable identification. The complete procedure was validated using the standard-addition calibration method, determining matrix effects on the studied compounds. Harmalol, harmine, and harmaline were naturally present in the samples and were quantified at very low concentrations, ranging from 7 to 24 µg kg(-1) dry algae.

Nonaqueous capillary electrophoresis as separation technique to support metabolism studies by means of electrochemistry and mass spectrometry.

The first combination of electrochemistry (EC), NACE, and ESI-MS to mimic the metabolic fate of drugs is described. While the combination of EC, HPLC, and ESI-MS has been used for this purpose before, NACE is able to deliver valuable additional information about possible metabolites of harmane when compared to HPLC. In this paper, NACE is used as a comprehensive separation technique in metabolism studies of harmane, a naturally occurring monoaminooxidase inhibitor, since it exhibits beneficial properties for the separation of polar compounds. Harmane is known to be metabolized via the oxidative metabolism catalyzed by cytochrome P450 enzymes, which are the most important metabolizing superfamily of enzymes in the human liver. The application of HPLC and NACE enabled the detection of 37 products in total, with 14 different mass-to-charge ratios. A total of 31 products could be detected in HPLC-MS and 26 in NACE-MS analysis. The combination of both NACE and RP-HPLC allows the identification of significantly more potential metabolites than any of the separation techniques alone.

A miniaturized matrix solid-phase dispersion methodology (µMSPD) for determination of ß-carboline alkaloids in tobacco samples by UPLC-ESI-Q-TOF/MSE.

Alkaloids play an important role in the chemical composition of tobacco, due to their effects that have led to the global consumption of this commodity. The ß-carboline alkaloids present inhibitory action against the enzyme monoamine oxidase (MAO), which enhances the susceptibility to chemical dependence in smokers. There is a need for scientific studies to ensure the correct identification and quantification of these compounds in tobacco matrices. In this work, we present the development and validation of a microextraction analytical method for determination and quantification of the alkaloids harmaline, harmalol, harmane, harmine, norharmane, and tetrahydroharmine in natural and processed samples of tobacco, employing micro-matrix solid-phase dispersion (µMSPD), ultra-performance liquid chromatography (UPLC), and mass spectrometry (MS). The optimized µMSPD procedure employed of 0.01 g of sample, 0.1 g of Discovery® DPA-6S adsorbent, and elution with 2 mL of aqueous 1 % formic acid solution, resulting in a fast, practical, economical, and environmentally friendly technique. Validation of the methodology showed that it presented good linearity (R2 > 0.9945), satisfactory accuracy and precision (in the range from 72 ± 16 % to 109 ± 9 %), and limits of quantification (LOQ) and detection (LOD) in the ranges 0.02-1.0 µg g-1 and 0.01-0.2 µg g-1, respectively. The developed method was applied to tobacco samples, proving to be efficient for determination of ß-carboline alkaloids. The compounds harmane and norharmane were quantified in samples of fresh tobacco leaves, cured tobacco leaves, twisted tobacco, and cigarettes. Harmine was only not quantified in the cigarettes.

Selective drug trace detection with low-field NMR.

Advances with para-hydrogen induced polarization open up new fields of applications for portable low-field NMR. Here we report the possibility of tracing drugs down to the micromolar regime. We could selectively polarize nicotine quantities similar to those found in one cigarette. Also less than 1 mg of harmine, a drug used for treatment of Parkinson's disease, and morphine extracted from an opium solution were detectable after polarization with para-hydrogen in single-scan (1)H-experiments. Moreover, we demonstrate the possibility to selectively enhance and detect the (1)H-signal of drug molecules with PHIP in proton rich standard solutions that would otherwise mask the (1)H NMR signal of the drug.

HPLC fingerprints combined with principal component analysis, hierarchical cluster analysis and linear discriminant analysis for the classification and differentiation of Peganum sp. indigenous to China.

INTRODUCTION: Seeds of wild Peganum harmala Linn., P. multisectum (Maxim) Bobr., P. nigellastrum Bunge and a probable indeterminate species, herein referred to as P. variety, are commonly used in Chinese medicine. These seeds cannot be differentiated based on morphology. OBJECTIVE: Seeds of P. harmala Linn., P. multisectum (Maxim) Bobr., P. nigellastrum Bunge and P. variety were collected in different provinces in China and their HPLC profiles were recorded for statistical analysis and pattern recognition.Methodology - HPLC chromatograms of seed extracts were recorded under the same conditions. Individual HPLC chromatograms for each species were evaluated against the mean chromatogram for the same species generated using a similarity evaluation computer program. Data from chromatographic fingerprints were also processed using principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA). RESULTS: The Peganum sp. seed extracts had similar HPLC fingerprints but with some inter-specific differences. The chromatographic fingerprints combined with PCA, HCA and LDA could distinguish the seeds of the different species of Peganum investigated. CONCLUSION: HPLC fingerprints can be used to authenticate and differentiate the seeds of three different species of genus Peganum indigenous to China. The results indicated that the unidentified P. variety might indeed be a new species or variety.

A rapid analytical strategy for the determination of ayahuasca alkaloids in non-ritualistic approaches by UHPLC-MS/MS.

INTRODUCTION: Ayahuasca is a beverage composed by a mixture of herbs which contain the compound N,N-dimethyltriptamine (DMT) and the ß-carbolines. Although its use is legalized in Brazil only for religious and spiritual ceremonies, there is a growing black market specialized in the distribution of these compounds in form of herbal material through internet and mail. The purpose of this work was the development of an ultra-high-performance liquid chromatography-tandem mass spectrometry method for the determination of ayahuasca alkaloids and its application in seized ayahuasca products. METHODS: An aliquot of seized products was weighted and diluted with methanol. An aliquot of this solution was added with internal standard (DMT-d6), followed by injection in the analytical system. RESULTS: The limit of quantitation was 10ng/mL for DMT and 25ng/mL for harmine, harmaline and tetrahydroharmine. The concentration ranges used were 10-100ng/mL for DMT, harmine and harmaline and all analytes presented a coefficient of determination (r2)≥0,99. Analysis of four seized samples presented concentrations of DMT ranging between 31.5 and 46.5mg/g. Presence of ß-carbolines was not detected in the products. The variability of DMT concentrations can be correlated with the potential intoxications described in the literature. CONCLUSION: This work successfully established a determination method for ayahuasca alkaloids in herbal material. In addition, the workflow proved to be simple, rapid and useful to estimate the concentration of psychoactive compounds in seized materials, leading to further investigation of ayahuasca ritualistic or recreational exposure.

Simultaneous generation of acrylamide, ß-carboline heterocyclic amines and advanced glycation ends products in an aqueous Maillard reaction model system.

The simultaneous formation of acrylamide; ß-carboline heterocyclic amines (HAs): harmane and norharmane; and advanced glycation end products (AGEs) (Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL)) was analyzed based on an aqueous model system. The model systems included lysine-glucose (Lys/Glu), asparagine-glucose (Asn/Glu), tryptophan-glucose (Trp/Glu), and a mixture of these amino acids (Mix/Glu). Only AGEs were generated when heated at 100 °C, Asn and Trp competed with Lys for glucose and methylglyoxal (MGO), and glyoxal (GO) decreased AGE content. The k value of CML, CEL, and acrylamide decreased when heated at 130 °C, whereas that of harmane increased in the Mix/Glu, owing to the competition between Lys and Asn for glucose, GO, and MGO. Harmane preferably formed via the Pictet-Spengler condensation between Trp and acetaldehyde, which further reduced acrylamide formation via the acrolein pathway.

ß-carbolines norharman and harman in vegetable oils in China.

The beta-carbolines norharman and harman, two heterocyclic aromatic amines with potential mutagenicity, have been determined in vegetable oils. Identification and analysis were carried out by ultra-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS/MS). In 88 samples analysed, the concentrations of norharman and harman were < LOD to 336.22 ng/g and < LOD to 505.14 ng/g, respectively. A high variability of norharman and harman levels among different oil types was observed. Sesame-, flaxseed-, sunflower seed-, peanut- and rapeseed oils were most contaminated. Both ß-carbolines were most likely formed during roasting of the oilseeds. Oil consumption, especially of oils obtained after roasting of the seeds, was a major dietary source of the ß-carbolines norharman and harman. Under existing oil risk factors, this investigation contributes to the unprecedented and essential information for dietary assessments associated with oil consumption.

Validation of an analytical method for the determination of the main ayahuasca active compounds and application to real ayahuasca samples from Brazil.

Ayahuasca is a brew prepared from the water decoction of two Amazonian plants, which is legally used for religious, cultural or therapeutic activities. The potential use of ayahuasca as a natural or phytotherapeutic drug is directly linked to the action of its active compounds and their connection with the therapeutic efficacy of the beverage. In this context, the aim of the present study was to establish a selective, sensitive and reproducible analytical method for the quantification of the main active ayahuasca compounds. Thirty-eight samples from the state of São Paulo, Brazil, were analyzed and the simultaneous quantifications of N,N-dimethyltryptamine (DMT), tetrahydroharmine (THH), harmine (HME) and harmaline (HML) were performed. This study enabled the development of a fast validated analytical method with minimal matrix interference and high reproducibility for the tracing of active ayahuasca compound concentrations for the first time. This method is important as an auxiliary tool for the study of active compound effects in biological responses using different multi-omic platforms.

Cooking with elaborate recipes can reduce the formation of mutagenic heterocyclic amines and promote co-mutagenic amines.

Heterocyclic amines (HCAs) are foodborne carcinogens for which their formation is highly dependent on cooking conditions. HCAs have been commonly quantified in food items prepared with simple procedures. This approach is suitable for elucidating HCAs' formation, but it only partially reflects the contamination in consumed food. In the current investigation, the generation of HCAs has been investigated in fried beef items prepared with elaborated cooking recipes, and their occurrence has been compared with control beef fried without the addition of ingredients other than oil. The food recipes that included a variety of food ingredients had lower yields of mutagenic HCAs (≥47% reduction, with individual HCA levels ranging between 0.01 and 2.22 ng/g) with respect to the control beef. In contrast, the co-mutagens norharman and harman were formed generally at greater levels (up to three times the contamination in the control fried beef) in the items prepared including a greater variety of ingredients.

Use of liquid chromatography quadrupole time-of-flight mass spectrometry and metabolomic approach to discriminate coffee brewed by different methods.

An untargeted metabolomic method based on UPLC-QTOF were used to investigate the differences in coffee brewed by boiled, pour-over and cold-brew methods here. Distinctive separation among the three groups could be seen from principal component analysis and hierarchical clustering analysis. Analysis of variance, fold change and orthogonal projection to latent structures discriminant mode were conducted to find the characteristic potential markers, subsequently, nine potential markers were putatively identified using general chemical databases, and five of them were further confirmed by acquisition of reference standards. This work provides an efficient way for discrimination of coffee brewed by different methods. Interestingly, the result of this work also suggested that the contents of two selected markers, norharman and harman, were higher in the pour-over and boiled methods, compared to the cold-brew method. This content difference were further verified by the quantitative analysis data of commercial coffee samples.

Bioactive ß-Carbolines in Food: A Review.

Harman and norharman, two neuroactive ß-carbolines, are present in several plants and in thermally processed foods. They exhibited a wide spectrum of biological and pharmacological effects, including antioxidant, neuroprotective, and anti-inflammatory effects. In this article, we review the progress of recent research on the presence of these compounds in food, as well as their various biological and neuroactive properties. Our findings strongly suggest that some foods, especially coffee, can act as a rich source of ß-carbolines, which may possibly be associated with a reduced risk for serious neurodegenerative diseases, such as Parkinson's and Alzheimer's.

Influence of the presence of methyl cyclodextrins in high-performance liquid chromatography mobile phases on the separation of beta-carboline alkaloids.

The presence of cyclodextrins (CDs) in the mobile phase alters the chromatographic equilibria and induces a secondary chemical equilibrium associated to the chromatographic separation by HPLC. In this study the influence of the presence of CDs in the mobile phase as chemically modified beta-CDs, i.e. 2,3-di-O-methyl-beta-cyclodextrin (DMbeta-CD) and 2,3,6-tri-O-methyl-beta-cyclodextrin (TMbeta-CD) on the separation of the alkaloids norharmane, harmane and harmine is described. These beta-carboline alkaloids are chemically and structurally related and their quantitation by RP-HPLC is of interest due to their biological and pharmacological properties. Two stationary phases (methyl-, C(1) and octadecyl-, C(18)) were employed, with methanol:buffered aqueous solution and ethanol:buffered aqueous solution as mobile phases. The role of tert-butyl alcohol as a mobile phase modifier and also as an inclusion complex stabiliser was also considered. The concentrations of DMbeta-CD and TMbeta-CD vary from 0 to 17 mM. The presence of increasing amounts of CDs in the mobile phase reduces the retention factor. The changes observed in the retention factor allow the determination of the alkaloid/CD apparent association constants, whose magnitude is influenced by the chemical and structural properties of the guest molecules but also by the composition of the mobile phase. Assuming a 1:1 stoichiometry for the inclusion complexes, the apparent association constants obtained were higher for norharmane and for both DMbeta-CD and TMbeta-CD. The strength of the complexes is higher for DMbeta-CD than for TMbeta-CD and this behaviour can be explained considering the steric problems associated to the permethylated-beta-CDs. Besides significant differences in the magnitude of the apparent association constants were observed for the two stationary phases employed and thus can be related to the adsorption of CDs on the stationary phase. A significant reduction in the proportion of organic solvent in the mobile phase (50%) without a decrease in the selectivity or resolution of the separation is a favourable consequence of the presence of the CDs in the mobile phase.

High-performance thin-layer chromatography densitometric method for the quantification of harmine, harmaline, vasicine, and vasicinone in Peganum harmala.

Peganum harmala Linn. seed is a reputed drug of the Indian systems of medicine. We report a simple high-performance thin-layer chromatography (HPTLC) densitometric method for the quantification of 4 alkaloids, viz., harmine, harmaline, vasicine, and vasicinone from P. harmala seed. The 4 compounds were resolved in ethyl acetate-methanol-ammonia (7 + 1 + 0.3, v/v/v) mobile phase. The method was validated for precision, repeatability, and accuracy. Instrumental precision was 0.27, 1.53, 0.39, and 1.15% [relative standard deviation (RSD)] and repeatability of the method was 1.01, 0.79, 0.13, and 1.62% RSD for harmine, harmaline, vasicine, and vasicinone, respectively. Accuracy of the method was checked by a recovery study conducted at 3 different levels, and the average recovery was 97.88% for harmine, 97.69% for harmaline, 98.38% for vasicine, and 98.28% for vasicinone. The 4 compounds were quantified in P. harmala seed using the method, and it was found to contain 0.44, 0.096, 0.25, and 0.0007% (w/w) of each, respectively. The proposed HPTLC densitometric method for the quantification of the 4 compounds was found to be simple, precise, specific, sensitive, and accurate. It can be used for routine quality control of P. harmala seed and has the ability to quantify the 4 marker compounds in the formulations containing P. harmala. It also can be used to quantify any of these marker compounds in other herbal drugs.

Effect of norharmane in vitro on juvenile hormone epoxide hydrolase activity in the lower termite, Reticulitermes speratus.

The aromatic beta-carboline norharmane was determined in workers, nymphs, and ergatoids of Reticulitermes speratus (Kolbe) (Isoptera: Rhinotermitidae) by gas chromatography/mass spectrometry. Norharmane levels in workers, nymphs, and ergatoids collected in May (approximately 4.3 ng/termite) were higher than those in November (approximately 0.2 ng/termite). Fluorescence of norharmane was observed in histological sections in whole animals and in the fat body. Norharmane, at a final concentration of 1 mM, stimulated juvenile hormone epoxide hydrolase (JHEH) activity of enzyme extract from ergatoids, but inhibited JHEH activity at higher concentrations. The elevated JHEH activity stimulated by norharmane should accelerate juvenile hormone metabolism in R. speratus.

Bioactivity of selected materials for coffee substitute.

Epidemiological studies have suggested that coffee consumption is negatively correlated with the incidence of Parkinson's disease. Coffee contains relatively high levels of ß-carbolines, which have been ascribed neuroactive effects in humans however the positive or negative effect has not been confirmed yet. Two ingredients with applications as coffee substitutes-chicory, which is traditionally used in this way, and artichoke-were considered in this study both from the neuroactive point of view but also in relation to the other bioactive compounds that result from their thermal processing. These thermal products are of concern because of their possible toxic properties. The estimated concentration of ß-carbolines was high in both materials (1.8 µg/g and 2.5 µg/g harman and 2.9 µg/g and 3.1 µg/g norharman in chicory and artichoke, respectively). Artichoke had more ß-carbolines than chicory, and also more all the toxic compounds examined here-acrylamide, carboxymethyllysine, and furans, which were detected in significantly higher concentrations in artichoke, particularly acrylamide. Chicory and artichoke also contain phenolic compounds that possess high antioxidant activity, on a similar level. Artichoke, a new proposed ingredient in coffee substitutes, appears to be a richer source of ß-carbolines than the traditionally chicory. Both materials contained high level of undesirable components, such as furan and its derivatives, carboxymethyllysine and particularly acrylamide, much higher in artichoke.

Factors influencing the norharman and harman contents in espresso coffee.

Espresso coffee (EC) brews were analyzed for beta-carboline [norharman (NH) and harman (H)] contents, by RP-HPLC with fluorescence detection. The influence of the coffee species (arabica or robusta), the roast degree, and the brew length was studied. The results show that the content of NH and H in EC is dependent primarily on the coffee species, followed by brew length. The roast degree has only a minor influence on the final content of NH and H in EC. When compared with other coffee brews, EC has an amount of these beta-carbolines (in micrograms per liter) similar to that of mocha coffee, both being more concentrated than filter and press-pot coffees. Therefore, the consumer's preferences will determine the amount of NH and H ingested daily. For the caffeinated 30 mL of EC, the arabica coffees contain about 4.08 microg of NH and 1.54 microg of H. Commercial blends (usually with a maximum of 30% robusta) range from the cited arabica values to 10.37 microg of NH and 4.35 microg of H.

Quantification of the neurotoxic beta-carboline harmane in barbecued/grilled meat samples and correlation with level of doneness.

Harmane, one of the heterocyclic amines (HCAs), is a potent neurotoxin linked to human diseases. Dietary exposure, especially in cooked meats, is the major source of exogenous exposure for humans. However, knowledge of harmane concentrations in cooked meat samples is limited. Our goals were to (1) quantify the concentration of harmane in different types of cooked meat samples, (2) compare its concentration to that of other more well-understood HCAs, and (3) examine the relationship between harmane concentration and level of doneness. Thirty barbecued/grilled meat samples (8 beef steak, 12 hamburger, 10 chicken) were analyzed for harmane and four other HCAs (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine [PhIP], amino-3,8-dimethylimidazo[4,5-f]quinoxaline [MeIQx], 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline [DiMeIQx], and 2-amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]pyridine [IFP]). Mean (+/- SD) harmane concentration was 5.63 (+/- 6.63) ng/g; harmane concentration was highest in chicken (8.48 +/- 9.86 ng/g) and lowest in beef steak (3.80 +/- 3.6 ng/g). Harmane concentration was higher than that of the other HCAs and significantly correlated with PhIP concentration. Harmane concentration was associated with meat doneness in samples of cooked beef steak and hamburger, although the correlation between meat doneness and concentration was greater for PhIP than for harmane. Evidence indicates that harmane was detectable in nanograms per gram quantities in cooked meat (especially chicken) and, moreover, was more abundant than other HCAs. There was some correlation between meat doneness and harmane concentration, although this correlation was less robust than that observed for PhIP. Data such as these may be used to improve estimation of human dietary exposure to this neurotoxin.